Pacemaker Administration

Managing Pacemaker Clusters

Abstract

This document has instructions and tips for system administrators who manage high-availability clusters using Pacemaker.

Table of Contents

1. Introduction

1.1. The Scope of this Document

The purpose of this document is to help system administrators learn how to manage a Pacemaker cluster.

System administrators may be interested in other parts of the Pacemaker documentation set such as Clusters from Scratch, a step-by-step guide to setting up an example cluster, and Pacemaker Explained, an exhaustive reference for cluster configuration.

Multiple higher-level tools (both command-line and GUI) are available to simplify cluster management. However, this document focuses on the lower-level command-line tools that come with Pacemaker itself. The concepts are applicable to the higher-level tools, though the syntax would differ.

1.2. What Is Pacemaker?

Pacemaker is a high-availability cluster resource manager – software that runs on a set of hosts (a cluster of nodes) in order to preserve integrity and minimize downtime of desired services (resources). [1] It is maintained by the ClusterLabs community.

Pacemaker’s key features include:

• Detection of and recovery from node- and service-level failures
• Ability to ensure data integrity by fencing faulty nodes
• Support for one or more nodes per cluster
• Support for multiple resource interface standards (anything that can be scripted can be clustered)
• Support (but no requirement) for shared storage
• Support for practically any redundancy configuration (active/passive, N+1, etc.)
• Automatically replicated configuration that can be updated from any node
• Ability to specify cluster-wide relationships between services, such as ordering, colocation, and anti-colocation
• Support for advanced service types, such as clones (services that need to be active on multiple nodes), promotable clones (clones that can run in one of two roles), and containerized services
• Unified, scriptable cluster management tools

Note

Fencing

Fencing, also known as STONITH (an acronym for Shoot The Other Node In The Head), is the ability to ensure that it is not possible for a node to be running a service. This is accomplished via fence devices such as intelligent power switches that cut power to the target, or intelligent network switches that cut the target’s access to the local network.

Pacemaker represents fence devices as a special class of resource.

A cluster cannot safely recover from certain failure conditions, such as an unresponsive node, without fencing.

1.2.1. Cluster Architecture

At a high level, a cluster can be viewed as having these parts (which together are often referred to as the cluster stack):

• Resources: These are the reason for the cluster’s being – the services that need to be kept highly available.
• Resource agents: These are scripts or operating system components that start, stop, and monitor resources, given a set of resource parameters. These provide a uniform interface between Pacemaker and the managed services.
• Fence agents: These are scripts that execute node fencing actions, given a target and fence device parameters.
• Cluster membership layer: This component provides reliable messaging, membership, and quorum information about the cluster. Currently, Pacemaker supports Corosync as this layer.
• Cluster resource manager: Pacemaker provides the brain that processes and reacts to events that occur in the cluster. These events may include nodes joining or leaving the cluster; resource events caused by failures, maintenance, or scheduled activities; and other administrative actions. To achieve the desired availability, Pacemaker may start and stop resources and fence nodes.
• Cluster tools: These provide an interface for users to interact with the cluster. Various command-line and graphical (GUI) interfaces are available.

Most managed services are not, themselves, cluster-aware. However, many popular open-source cluster filesystems make use of a common Distributed Lock Manager (DLM), which makes direct use of Corosync for its messaging and membership capabilities and Pacemaker for the ability to fence nodes.

1.2.2. Pacemaker Architecture

Pacemaker itself is composed of multiple daemons that work together:

• pacemakerd
• pacemaker-attrd
• pacemaker-based
• pacemaker-controld
• pacemaker-execd
• pacemaker-fenced
• pacemaker-schedulerd

Pacemaker’s main process (pacemakerd) spawns all the other daemons, and respawns them if they unexpectedly exit.

The Cluster Information Base (CIB) is an XML representation of the cluster’s configuration and the state of all nodes and resources. The CIB manager (pacemaker-based) keeps the CIB synchronized across the cluster, and handles requests to modify it.

The attribute manager (pacemaker-attrd) maintains a database of attributes for all nodes, keeps it synchronized across the cluster, and handles requests to modify them. These attributes are usually recorded in the CIB.

Given a snapshot of the CIB as input, the scheduler (pacemaker-schedulerd) determines what actions are necessary to achieve the desired state of the cluster.

The local executor (pacemaker-execd) handles requests to execute resource agents on the local cluster node, and returns the result.

The fencer (pacemaker-fenced) handles requests to fence nodes. Given a target node, the fencer decides which cluster node(s) should execute which fencing device(s), and calls the necessary fencing agents (either directly, or via requests to the fencer peers on other nodes), and returns the result.

The controller (pacemaker-controld) is Pacemaker’s coordinator, maintaining a consistent view of the cluster membership and orchestrating all the other components.

Pacemaker centralizes cluster decision-making by electing one of the controller instances as the Designated Controller (DC). Should the elected DC process (or the node it is on) fail, a new one is quickly established. The DC responds to cluster events by taking a current snapshot of the CIB, feeding it to the scheduler, then asking the executors (either directly on the local node, or via requests to controller peers on other nodes) and the fencer to execute any necessary actions.

Note

Old daemon names

The Pacemaker daemons were renamed in version 2.0. You may still find references to the old names, especially in documentation targeted to version 1.1.

Old name	New name
attrd	pacemaker-attrd
cib	pacemaker-based
crmd	pacemaker-controld
lrmd	pacemaker-execd
stonithd	pacemaker-fenced
pacemaker_remoted	pacemaker-remoted

1.2.3. Node Redundancy Designs

Pacemaker supports practically any node redundancy configuration including Active/Active, Active/Passive, N+1, N+M, N-to-1, and N-to-N.

Active/passive clusters with two (or more) nodes using Pacemaker and DRBD are a cost-effective high-availability solution for many situations. One of the nodes provides the desired services, and if it fails, the other node takes over.

Pacemaker also supports multiple nodes in a shared-failover design, reducing hardware costs by allowing several active/passive clusters to be combined and share a common backup node.

When shared storage is available, every node can potentially be used for failover. Pacemaker can even run multiple copies of services to spread out the workload. This is sometimes called N-to-N redundancy.

Footnotes

[1]	Cluster is sometimes used in other contexts to refer to hosts grouped together for other purposes, such as high-performance computing (HPC), but Pacemaker is not intended for those purposes.

2. Installing Cluster Software

Most major Linux distributions have pacemaker packages in their standard package repositories, or the software can be built from source code. See How to Install on the ClusterLabs wiki for details.

3. The Cluster Layer

Pacemaker utilizes an underlying cluster layer for two purposes:

• obtaining quorum
• messaging between nodes

Currently, only Corosync 2 and later is supported for this layer.

This document assumes you have configured the cluster nodes in Corosync already. High-level cluster management tools are available that can configure Corosync for you. If you want the lower-level details, see the Corosync documentation.

4. Client Options

Pacemaker uses several environment variables set on the client side.

Note

Directory and file paths below may differ on your system depending on your Pacemaker build settings. Check your Pacemaker configuration file to find the correct paths.

Client-side Environment Variables

Environment Variable	Default	Description
CIB_encrypted	true	Whether to encrypt network traffic. Used with CIB_port for connecting to a remote CIB instance; ignored if CIB_port is not set.
CIB_file		If set, CIB connections are created against the named XML file. Clients read an input CIB from, and write the result CIB to, the named file. Ignored if CIB_shadow is set.
CIB_passwd		$CIB_user’s password. Read from the command line if unset. Used with CIB_port for connecting to a remote CIB instance; ignored if CIB_port is not set.
CIB_port		If set, CIB connections are created as clients to a remote CIB instance on $CIB_server via this port. Ignored if CIB_shadow or CIB_file is set.
CIB_server	localhost	The host to connect to. Used with CIB_port for connecting to a remote CIB instance; ignored if CIB_port is not set.
CIB_shadow		If set, CIB connections are created against a temporary working (“shadow”) CIB file called shadow.$CIB_shadow in $CIB_shadow_dir. Should be set only to the name of a shadow CIB created by crm_shadow. Otherwise, behavior is undefined.
CIB_shadow_dir	/var/lib/pacemaker/cib if the current user is root or hacluster; otherwise $HOME/.cib if $HOME is set; otherwise $TMPDIR/.cib if $TMPDIR is set to an absolute path; otherwise /tmp/.cib	If set, shadow files are created in this directory. Ignored if CIB_shadow is not set.
CIB_user	hacluster if used with CIB_port, or the current effective user otherwise	If used with CIB_port, connect to $CIB_server as this user. Must be part of the haclient group on $CIB_server. Otherwise (without CIB_port), this is used only for ACL and display purposes.
EDITOR		Text editor to use for editing shadow files. Required for the --edit command of crm_shadow.
HOME	Current user’s home directory as configured in the passwd database, if an entry exists	Used to create a default CIB_shadow_dir for non- privileged users.
PE_fail	0	Advanced use only: A dummy graph action with action ID matching this option will be marked as failed. Primarily for developer use with scheduler simulations.
PS1		The shell’s primary prompt string. Used by crm_shadow: set to indicate that the user is in an interactive shadow CIB session, and checked to determine whether the user is already in an interactive session before creating a new one.
SHELL		Absolute path to a shell. Used by crm_shadow when launching an interactive session.
TMPDIR	/tmp	Directory for temporary files. If not an absolute path, the default is used instead.

5. Configuring Pacemaker

Pacemaker’s configuration, the CIB, is stored in XML format. Cluster administrators have multiple options for modifying the configuration either via the XML, or at a more abstract (and easier for humans to understand) level.

Pacemaker reacts to configuration changes as soon as they are saved. Pacemaker’s command-line tools and most higher-level tools provide the ability to batch changes together and commit them at once, rather than make a series of small changes, which could cause avoid unnecessary actions as Pacemaker responds to each change individually.

Pacemaker tracks revisions to the configuration and will reject any update older than the current revision. Thus, it is a good idea to serialize all changes to the configuration. Avoid attempting simultaneous changes, whether on the same node or different nodes, and whether manually or using some automated configuration tool.

Note

It is not necessary to update the configuration on all cluster nodes. Pacemaker immediately synchronizes changes to all active members of the cluster. To reduce bandwidth, the cluster only broadcasts the incremental updates that result from your changes and uses checksums to ensure that each copy is consistent.

5.1. Configuration Using Higher-level Tools

Most users will benefit from using higher-level tools provided by projects separate from Pacemaker. Popular ones include the crm shell and pcs. [1]

See those projects’ documentation for details on how to configure Pacemaker using them.

5.2. Configuration Using Pacemaker’s Command-Line Tools

Pacemaker provides lower-level, command-line tools to manage the cluster. Most configuration tasks can be performed with these tools, without needing any XML knowledge.

To enable STONITH for example, one could run:

# crm_attribute --name stonith-enabled --update 1

Or, to check whether node1 is allowed to run resources, there is:

# crm_standby --query --node node1

Or, to change the failure threshold of my-test-rsc, one can use:

# crm_resource -r my-test-rsc --set-parameter migration-threshold --parameter-value 3 --meta

Examples of using these tools for specific cases will be given throughout this document where appropriate. See the man pages for further details.

See Edit the CIB XML with cibadmin for how to edit the CIB using XML.

See Batch Configuration Changes with crm_shadow for a way to make a series of changes, then commit them all at once to the live cluster.

5.2.1. Working with CIB Properties

Although these fields can be written to by the user, in most cases the cluster will overwrite any values specified by the user with the “correct” ones.

To change the ones that can be specified by the user, for example admin_epoch, one should use:

# cibadmin --modify --xml-text '<cib admin_epoch="42"/>'

A complete set of CIB properties will look something like this:

XML attributes set for a cib element

<cib crm_feature_set="3.0.7" validate-with="pacemaker-1.2"
   admin_epoch="42" epoch="116" num_updates="1"
   cib-last-written="Mon Jan 12 15:46:39 2015" update-origin="rhel7-1"
   update-client="crm_attribute" have-quorum="1" dc-uuid="1">

5.2.2. Querying and Setting Cluster Options

Cluster options can be queried and modified using the crm_attribute tool. To get the current value of cluster-delay, you can run:

# crm_attribute --query --name cluster-delay

which is more simply written as

# crm_attribute -G -n cluster-delay

If a value is found, you’ll see a result like this:

# crm_attribute -G -n cluster-delay
scope=crm_config name=cluster-delay value=60s

If no value is found, the tool will display an error:

# crm_attribute -G -n clusta-deway
scope=crm_config name=clusta-deway value=(null)
Error performing operation: No such device or address

To use a different value (for example, 30 seconds), simply run:

# crm_attribute --name cluster-delay --update 30s

To go back to the cluster’s default value, you can delete the value, for example:

# crm_attribute --name cluster-delay --delete
Deleted crm_config option: id=cib-bootstrap-options-cluster-delay name=cluster-delay

5.2.3. When Options are Listed More Than Once

If you ever see something like the following, it means that the option you’re modifying is present more than once.

Deleting an option that is listed twice

# crm_attribute --name batch-limit --delete

Please choose from one of the matches below and supply the 'id' with --id
Multiple attributes match name=batch-limit in crm_config:
Value: 50          (set=cib-bootstrap-options, id=cib-bootstrap-options-batch-limit)
Value: 100         (set=custom, id=custom-batch-limit)

In such cases, follow the on-screen instructions to perform the requested action. To determine which value is currently being used by the cluster, refer to the “Rules” chapter of Pacemaker Explained.

5.3. Connecting from a Remote Machine

It is possible to run configuration commands from a machine that is not part of the cluster.

For security reasons, this capability is disabled by default. If you wish to allow remote access, set the remote-tls-port (encrypted) or remote-clear-port (unencrypted) CIB properties (attributes of the cib element). Encrypted communication is keyless, which makes it subject to man-in-the-middle attacks, so either option should be used only on protected networks.

The administrator’s machine simply needs Pacemaker installed. To connect to the cluster, set the following environment variables:

• CIB_port (required)
• CIB_server
• CIB_user
• CIB_passwd
• CIB_encrypted

Only the Pacemaker daemon user (hacluster) may be used as CIB_user.

As an example, if node1 is a cluster node, and the CIB is configured with remote-tls-port set to 1234, the administrator could read the current cluster configuration using the following commands, and would be prompted for the daemon user’s password:

# export CIB_server=node1; export CIB_port=1234; export CIB_encrypted=true
# cibadmin -Q

Note

Pacemaker must have been built with PAM support in order for Pacemaker to authenticate the user credentials. In a build without PAM support, all remote connections are accepted without authentication. You can check for PAM support (since 2.1.9) by running pacemakerd --features. If the output contains pam, authentication is supported.

Footnotes

[1]	For a list, see “Configuration Tools” at https://clusterlabs.org/components.html

6. Using Pacemaker Command-Line Tools

6.1. Controlling Command Line Output

Some of the pacemaker command line utilities have been converted to a new output system. Among these tools are crm_mon and stonith_admin. This is an ongoing project, and more tools will be converted over time. This system lets you control the formatting of output with --output-as= and the destination of output with --output-to=.

The available formats vary by tool, but at least plain text and XML are supported by all tools that use the new system. The default format is plain text. The default destination is stdout but can be redirected to any file. Some formats support command line options for changing the style of the output. For instance:

# crm_mon --help-output
Usage:
  crm_mon [OPTION?]

Provides a summary of cluster's current state.

Outputs varying levels of detail in a number of different formats.

Output Options:
  --output-as=FORMAT                Specify output format as one of: console (default), html, text, xml
  --output-to=DEST                  Specify file name for output (or "-" for stdout)
  --html-cgi                        Add text needed to use output in a CGI program
  --html-stylesheet=URI             Link to an external CSS stylesheet
  --html-title=TITLE                Page title
  --text-fancy                      Use more highly formatted output

6.2. Monitor a Cluster with crm_mon

The crm_mon utility displays the current state of an active cluster. It can show the cluster status organized by node or by resource, and can be used in either single-shot or dynamically updating mode. It can also display operations performed and information about failures.

Using this tool, you can examine the state of the cluster for irregularities, and see how it responds when you cause or simulate failures.

See the manual page or the output of crm_mon --help for a full description of its many options.

Sample output from crm_mon -1

Cluster Summary:
  * Stack: corosync
  * Current DC: node2 (version 2.0.0-1) - partition with quorum
  * Last updated: Mon Jan 29 12:18:42 2018
  * Last change:  Mon Jan 29 12:18:40 2018 by root via crm_attribute      on node3
  * 5 nodes configured
  * 2 resources configured

Node List:
  * Online: [ node1 node2 node3 node4 node5 ]

* Active resources:
  * Fencing (stonith:fence_xvm):    Started node1
  * IP    (ocf:heartbeat:IPaddr2):        Started node2

Sample output from crm_mon -n -1

Cluster Summary:
  * Stack: corosync
  * Current DC: node2 (version 2.0.0-1) - partition with quorum
  * Last updated: Mon Jan 29 12:21:48 2018
  * Last change:  Mon Jan 29 12:18:40 2018 by root via crm_attribute      on node3
  * 5 nodes configured
  * 2 resources configured

* Node List:
  * Node node1: online
    * Fencing (stonith:fence_xvm):    Started
  * Node node2: online
    * IP  (ocf:heartbeat:IPaddr2):        Started
  * Node node3: online
  * Node node4: online
  * Node node5: online

As mentioned in an earlier chapter, the DC is the node is where decisions are made. The cluster elects a node to be DC as needed. The only significance of the choice of DC to an administrator is the fact that its logs will have the most information about why decisions were made.

6.2.1. Styling crm_mon HTML output

Various parts of crm_mon’s HTML output have a CSS class associated with them. Not everything does, but some of the most interesting portions do. In the following example, the status of each node has an online class and the details of each resource have an rsc-ok class.

<h2>Node List</h2>
<ul>
<li>
<span>Node: cluster01</span><span class="online"> online</span>
</li>
<li><ul><li><span class="rsc-ok">ping   (ocf::pacemaker:ping):   Started</span></li></ul></li>
<li>
<span>Node: cluster02</span><span class="online"> online</span>
</li>
<li><ul><li><span class="rsc-ok">ping   (ocf::pacemaker:ping):   Started</span></li></ul></li>
</ul>

By default, a stylesheet for styling these classes is included in the head of the HTML output. The relevant portions of this stylesheet that would be used in the above example is:

<style>
.online { color: green }
.rsc-ok { color: green }
</style>

If you want to override some or all of the styling, simply create your own stylesheet, place it on a web server, and pass --html-stylesheet=<URL> to crm_mon. The link is added after the default stylesheet, so your changes take precedence. You don’t need to duplicate the entire default. Only include what you want to change.

6.3. Edit the CIB XML with cibadmin

The most flexible tool for modifying the configuration is Pacemaker’s cibadmin command. With cibadmin, you can query, add, remove, update or replace any part of the configuration. All changes take effect immediately, so there is no need to perform a reload-like operation.

The simplest way of using cibadmin is to use it to save the current configuration to a temporary file, edit that file with your favorite text or XML editor, and then upload the revised configuration.

Safely using an editor to modify the cluster configuration

# cibadmin --query > tmp.xml
# vi tmp.xml
# cibadmin --replace --xml-file tmp.xml

Some of the better XML editors can make use of a RELAX NG schema to help make sure any changes you make are valid. The schema describing the configuration can be found in pacemaker.rng, which may be deployed in a location such as /usr/share/pacemaker depending on your operating system distribution and how you installed the software.

If you want to modify just one section of the configuration, you can query and replace just that section to avoid modifying any others.

Safely using an editor to modify only the resources section

# cibadmin --query --scope resources > tmp.xml
# vi tmp.xml
# cibadmin --replace --scope resources --xml-file tmp.xml

To quickly delete a part of the configuration, identify the object you wish to delete by XML tag and id. For example, you might search the CIB for all STONITH-related configuration:

Searching for STONITH-related configuration items

# cibadmin --query | grep stonith
 <nvpair id="cib-bootstrap-options-stonith-action" name="stonith-action" value="reboot"/>
 <nvpair id="cib-bootstrap-options-stonith-enabled" name="stonith-enabled" value="1"/>
 <primitive id="child_DoFencing" class="stonith" type="external/vmware">
 <lrm_resource id="child_DoFencing:0" type="external/vmware" class="stonith">
 <lrm_resource id="child_DoFencing:0" type="external/vmware" class="stonith">
 <lrm_resource id="child_DoFencing:1" type="external/vmware" class="stonith">
 <lrm_resource id="child_DoFencing:0" type="external/vmware" class="stonith">
 <lrm_resource id="child_DoFencing:2" type="external/vmware" class="stonith">
 <lrm_resource id="child_DoFencing:0" type="external/vmware" class="stonith">
 <lrm_resource id="child_DoFencing:3" type="external/vmware" class="stonith">

If you wanted to delete the primitive tag with id child_DoFencing, you would run:

# cibadmin --delete --xml-text '<primitive id="child_DoFencing"/>'

See the cibadmin man page for more options.

Warning

Never edit the live cib.xml file directly. Pacemaker will detect such changes and refuse to use the configuration.

6.4. Batch Configuration Changes with crm_shadow

Often, it is desirable to preview the effects of a series of configuration changes before updating the live configuration all at once. For this purpose, crm_shadow creates a “shadow” copy of the configuration and arranges for all the command-line tools to use it.

To begin, simply invoke crm_shadow --create with a name of your choice, and follow the simple on-screen instructions. Shadow copies are identified with a name to make it possible to have more than one.

Warning

Read this section and the on-screen instructions carefully; failure to do so could result in destroying the cluster’s active configuration!

Creating and displaying the active sandbox

# crm_shadow --create test
Setting up shadow instance
Type Ctrl-D to exit the crm_shadow shell
shadow[test]:
shadow[test] # crm_shadow --which
test

From this point on, all cluster commands will automatically use the shadow copy instead of talking to the cluster’s active configuration. Once you have finished experimenting, you can either make the changes active via the --commit option, or discard them using the --delete option. Again, be sure to follow the on-screen instructions carefully!

For a full list of crm_shadow options and commands, invoke it with the --help option.

Use sandbox to make multiple changes all at once, discard them, and verify real configuration is untouched

shadow[test] # crm_failcount -r rsc_c001n01 -G
scope=status  name=fail-count-rsc_c001n01 value=0
shadow[test] # crm_standby --node c001n02 -v on
shadow[test] # crm_standby --node c001n02 -G
scope=nodes  name=standby value=on

shadow[test] # cibadmin --erase --force
shadow[test] # cibadmin --query
<cib crm_feature_set="3.0.14" validate-with="pacemaker-3.0" epoch="112" num_updates="2" admin_epoch="0" cib-last-written="Mon Jan  8 23:26:47 2018" update-origin="rhel7-1" update-client="crm_node" update-user="root" have-quorum="1" dc-uuid="1">
  <configuration>
    <crm_config/>
    <nodes/>
    <resources/>
    <constraints/>
  </configuration>
  <status/>
</cib>
shadow[test] # crm_shadow --delete test --force
Now type Ctrl-D to exit the crm_shadow shell
shadow[test] # exit
# crm_shadow --which
No active shadow configuration defined
# cibadmin -Q
<cib crm_feature_set="3.0.14" validate-with="pacemaker-3.0" epoch="110" num_updates="2" admin_epoch="0" cib-last-written="Mon Jan  8 23:26:47 2018" update-origin="rhel7-1" update-client="crm_node" update-user="root" have-quorum="1">
   <configuration>
      <crm_config>
         <cluster_property_set id="cib-bootstrap-options">
            <nvpair id="cib-bootstrap-1" name="stonith-enabled" value="1"/>
            <nvpair id="cib-bootstrap-2" name="pe-input-series-max" value="30000"/>

See the next section, Simulate Cluster Activity with crm_simulate, for how to test your changes before committing them to the live cluster.

6.5. Simulate Cluster Activity with crm_simulate

The command-line tool crm_simulate shows the results of the same logic the cluster itself uses to respond to a particular cluster configuration and status.

As always, the man page is the primary documentation, and should be consulted for further details. This section aims for a better conceptual explanation and practical examples.

6.5.1. Replaying cluster decision-making logic

At any given time, one node in a Pacemaker cluster will be elected DC, and that node will run Pacemaker’s scheduler to make decisions.

Each time decisions need to be made (a “transition”), the DC will have log messages like “Calculated transition … saving inputs in …” with a file name. You can grab the named file and replay the cluster logic to see why particular decisions were made. The file contains the live cluster configuration at that moment, so you can also look at it directly to see the value of node attributes, etc., at that time.

The simplest usage is (replacing $FILENAME with the actual file name):

Simulate cluster response to a given CIB

# crm_simulate --simulate --xml-file $FILENAME

That will show the cluster state when the process started, the actions that need to be taken (“Transition Summary”), and the resulting cluster state if the actions succeed. Most actions will have a brief description of why they were required.

The transition inputs may be compressed. crm_simulate can handle these compressed files directly, though if you want to edit the file, you’ll need to uncompress it first.

You can do the same simulation for the live cluster configuration at the current moment. This is useful mainly when using crm_shadow to create a sandbox version of the CIB; the --live-check option will use the shadow CIB if one is in effect.

Simulate cluster response to current live CIB or shadow CIB

# crm_simulate --simulate --live-check

6.5.2. Why decisions were made

To get further insight into the “why”, it gets user-unfriendly very quickly. If you add the --show-scores option, you will also see all the scores that went into the decision-making. The node with the highest cumulative score for a resource will run it. You can look for -INFINITY scores in particular to see where complete bans came into effect.

You can also add -VVVV to get more detailed messages about what’s happening under the hood. You can add up to two more V’s even, but that’s usually useful only if you’re a masochist or tracing through the source code.

6.5.3. Visualizing the action sequence

Another handy feature is the ability to generate a visual graph of the actions needed, using the --save-dotfile option. This relies on the separate Graphviz [1] project.

Generate a visual graph of cluster actions from a saved CIB

# crm_simulate --simulate --xml-file $FILENAME --save-dotfile $FILENAME.dot
# dot $FILENAME.dot -Tsvg > $FILENAME.svg

$FILENAME.dot will contain a GraphViz representation of the cluster’s response to your changes, including all actions with their ordering dependencies.

$FILENAME.svg will be the same information in a standard graphical format that you can view in your browser or other app of choice. You could, of course, use other dot options to generate other formats.

How to interpret the graphical output:

• Bubbles indicate actions, and arrows indicate ordering dependencies
• Resource actions have text of the form <RESOURCE>_<ACTION>_<INTERVAL_IN_MS> <NODE> indicating that the specified action will be executed for the specified resource on the specified node, once if interval is 0 or at specified recurring interval otherwise
• Actions with black text will be sent to the executor (that is, the appropriate agent will be invoked)
• Actions with orange text are “pseudo” actions that the cluster uses internally for ordering but require no real activity
• Actions with a solid green border are part of the transition (that is, the cluster will attempt to execute them in the given order – though a transition can be interrupted by action failure or new events)
• Dashed arrows indicate dependencies that are not present in the transition graph
• Actions with a dashed border will not be executed. If the dashed border is blue, the cluster does not feel the action needs to be executed. If the dashed border is red, the cluster would like to execute the action but cannot. Any actions depending on an action with a dashed border will not be able to execute.
• Loops should not happen, and should be reported as a bug if found.

Small Cluster Transition

In the above example, it appears that a new node, pcmk-2, has come online and that the cluster is checking to make sure rsc1, rsc2 and rsc3 are not already running there (indicated by the rscN_monitor_0 entries). Once it did that, and assuming the resources were not active there, it would have liked to stop rsc1 and rsc2 on pcmk-1 and move them to pcmk-2. However, there appears to be some problem and the cluster cannot or is not permitted to perform the stop actions which implies it also cannot perform the start actions. For some reason, the cluster does not want to start rsc3 anywhere.

Complex Cluster Transition

6.5.4. What-if scenarios

You can make changes to the saved or shadow CIB and simulate it again, to see how Pacemaker would react differently. You can edit the XML by hand, use command-line tools such as cibadmin with either a shadow CIB or the CIB_file environment variable set to the filename, or use higher-level tool support (see the man pages of the specific tool you’re using for how to perform actions on a saved CIB file rather than the live CIB).

You can also inject node failures and/or action failures into the simulation; see the crm_simulate man page for more details.

This capability is useful when using a shadow CIB to edit the configuration. Before committing the changes to the live cluster with crm_shadow --commit, you can use crm_simulate to see how the cluster will react to the changes.

6.6. Manage Node Attributes, Cluster Options and Defaults with crm_attribute and attrd_updater

crm_attribute and attrd_updater are confusingly similar tools with subtle differences.

attrd_updater can query and update node attributes. crm_attribute can query and update not only node attributes, but also cluster options, resource defaults, and operation defaults.

To understand the differences, it helps to understand the various types of node attribute.

Types of Node Attributes

Type	Recorded in CIB?	Recorded in attribute manager memory?	Survive full cluster restart?	Manageable by crm_attribute?	Manageable by attrd_updater?
permanent	yes	no	yes	yes	no
transient	yes	yes	no	yes	yes
private	no	yes	no	no	yes

As you can see from the table above, crm_attribute can manage permanent and transient node attributes, while attrd_updater can manage transient and private node attributes.

The difference between the two tools lies mainly in how they update node attributes: attrd_updater always contacts the Pacemaker attribute manager directly, while crm_attribute will contact the attribute manager only for transient node attributes, and will instead modify the CIB directly for permanent node attributes (and for transient node attributes when unable to contact the attribute manager).

By contacting the attribute manager directly, attrd_updater can change an attribute’s “dampening” (whether changes are immediately flushed to the CIB or after a specified amount of time, to minimize disk writes for frequent changes), set private node attributes (which are never written to the CIB), and set attributes for nodes that don’t yet exist.

By modifying the CIB directly, crm_attribute can set permanent node attributes (which are only in the CIB and not managed by the attribute manager), and can be used with saved CIB files and shadow CIBs.

However a transient node attribute is set, it is synchronized between the CIB and the attribute manager, on all nodes.

6.7. Other Commonly Used Tools

Other command-line tools include:

• crm_failcount: query or delete resource fail counts
• crm_node: manage cluster nodes
• crm_report: generate a detailed cluster report for bug submissions
• crm_resource: manage cluster resources
• crm_standby: manage standby status of nodes
• crm_verify: validate a CIB
• stonith_admin: manage fencing devices

See the manual pages for details.

Footnotes

[1]	Graph visualization software. See http://www.graphviz.org/ for details.

7. Administrative Modes

Intrusive administration can be performed on a Pacemaker cluster without causing resource failures, recovery, and fencing, by putting the cluster or a subset of it into an administrative mode.

Pacemaker supports several administrative modes:

• Maintenance mode for the entire cluster, specific nodes, or specific resources
• Unmanaged resources
• Disabled configuration items
• Standby mode for specific nodes

Rules may be used to automatically set any of these modes for specific times or other conditions.

7.1. Maintenance Mode

In maintenance mode, the cluster will not start or stop resources. Recurring monitors for affected resources will be paused, except those specifying role as Stopped.

To put a specific resource into maintenance mode, set the resource’s maintenance meta-attribute to true.

To put all active resources on a specific node into maintenance mode, set the node’s maintenance node attribute to true. When enabled, this overrides resource-specific maintenance mode.

Warning

Restarting Pacemaker on a node that is in single-node maintenance mode will likely lead to undesirable effects. If maintenance is set as a transient attribute, it will be erased when Pacemaker is stopped, which will immediately take the node out of maintenance mode and likely get it fenced. If set as a permanent attribute, any resources active on the node will have their local history erased when Pacemaker is restarted, so the cluster will no longer consider them running on the node and thus will consider them managed again, allowing them to be started elsewhere.

To put all resources in the cluster into maintenance mode, set the maintenance-mode cluster option to true. When enabled, this overrides node- or resource- specific maintenance mode.

Maintenance mode, at any level, overrides other administrative modes.

7.2. Unmanaged Resources

An unmanaged resource will not be started or stopped by the cluster. A resource may become unmanaged in several ways:

• The administrator may set the is-managed resource meta-attribute to false (whether for a specific resource, or all resources without an explicit setting via rsc_defaults)
• Maintenance mode causes affected resources to become unmanaged (and overrides any is-managed setting)
• Certain types of failure cause affected resources to become unmanaged. These include:
  • Failed stop operations when the stonith-enabled cluster property is set to false
  • Failure of an operation that has on-fail set to block
  • A resource detected as incorrectly active on more than one node when its multiple-active meta-attribute is set to block
  • A resource constrained by a revoked rsc_ticket with loss-policy set to freeze
  • Resources with requires set (or defaulting) to anything other than nothing in a partition that loses quorum when the no-quorum-policy cluster option is set to freeze

Recurring actions are not affected by unmanaging a resource.

Warning

Manually starting an unmanaged resource on a different node is strongly discouraged. It will at least cause the cluster to consider the resource failed, and may require the resource’s target-role to be set to Stopped then Started in order for recovery to succeed.

7.3. Disabled Configuration

Some configuration elements disable particular behaviors:

• The stonith-enabled cluster option, when set to false, disables node fencing. This is highly discouraged, as it can lead to data unavailability, loss, or corruption.
• The stop-all-resources cluster option, when set to true, causes all resources to be stopped.
• Certain elements support an enabled meta-attribute, which if set to false, causes the cluster to act as if the specific element is not configured. These include op, alert (since 2.1.6), and recipient (since 2.1.6). enabled may be set for specific op elements, or all operations without an explicit setting via op_defaults.

7.4. Standby Mode

When a node is put into standby, all resources will be moved away from the node, and all recurring operations will be stopped on the node, except those specifying role as Stopped (which will be newly initiated if appropriate).

A node may be put into standby mode by setting its standby node attribute to true. The attribute may be queried and set using the crm_standby tool.

7.5. Rules

Rules may be used to set administrative mode options automatically according to various criteria such as date and time. See the “Rules” chapter of the Pacemaker Explained document for details.

8. Moving Resources

8.1. Moving Resources Manually

There are primarily two occasions when you would want to move a resource from its current location: when the whole node is under maintenance, and when a single resource needs to be moved.

8.1.1. Standby Mode

Since everything eventually comes down to a score, you could create constraints for every resource to prevent them from running on one node. While Pacemaker configuration can seem convoluted at times, not even we would require this of administrators.

Instead, you can set a special node attribute which tells the cluster “don’t let anything run here”. There is even a helpful tool to help query and set it, called crm_standby. To check the standby status of the current machine, run:

# crm_standby -G

A value of on indicates that the node is not able to host any resources, while a value of off says that it can.

You can also check the status of other nodes in the cluster by specifying the –node option:

# crm_standby -G --node sles-2

To change the current node’s standby status, use -v instead of -G:

# crm_standby -v on

Again, you can change another host’s value by supplying a hostname with --node.

A cluster node in standby mode will not run resources, but still contributes to quorum, and may fence or be fenced by nodes.

8.1.2. Moving One Resource

When only one resource is required to move, we could do this by creating location constraints. However, once again we provide a user-friendly shortcut as part of the crm_resource command, which creates and modifies the extra constraints for you. If Email were running on sles-1 and you wanted it moved to a specific location, the command would look something like:

# crm_resource -M -r Email -H sles-2

Behind the scenes, the tool will create the following location constraint:

<rsc_location id="cli-prefer-Email" rsc="Email" node="sles-2" score="INFINITY"/>

It is important to note that subsequent invocations of crm_resource -M are not cumulative. So, if you ran these commands:

# crm_resource -M -r Email -H sles-2
# crm_resource -M -r Email -H sles-3

then it is as if you had never performed the first command.

To allow the resource to move back again, use:

# crm_resource -U -r Email

Note the use of the word allow. The resource can move back to its original location, but depending on resource-stickiness, location constraints, and so forth, it might stay where it is.

To be absolutely certain that it moves back to sles-1, move it there before issuing the call to crm_resource -U:

# crm_resource -M -r Email -H sles-1
# crm_resource -U -r Email

Alternatively, if you only care that the resource should be moved from its current location, try:

# crm_resource -B -r Email

which will instead create a negative constraint, like:

<rsc_location id="cli-ban-Email-on-sles-1" rsc="Email" node="sles-1" score="-INFINITY"/>

This will achieve the desired effect, but will also have long-term consequences. As the tool will warn you, the creation of a -INFINITY constraint will prevent the resource from running on that node until crm_resource -U is used. This includes the situation where every other cluster node is no longer available!

In some cases, such as when resource-stickiness is set to INFINITY, it is possible that you will end up with nodes with the same score, forcing the cluster to choose one (which may not be the one you want). The tool can detect some of these cases and deals with them by creating both positive and negative constraints. For example:

<rsc_location id="cli-ban-Email-on-sles-1" rsc="Email" node="sles-1" score="-INFINITY"/>
<rsc_location id="cli-prefer-Email" rsc="Email" node="sles-2" score="INFINITY"/>

which has the same long-term consequences as discussed earlier.

8.2. Moving Resources Due to Connectivity Changes

You can configure the cluster to move resources when external connectivity is lost in two steps.

8.2.1. Tell Pacemaker to Monitor Connectivity

First, add an ocf:pacemaker:ping resource to the cluster. The ping resource uses the system utility of the same name to a test whether a list of machines (specified by DNS hostname or IP address) are reachable, and uses the results to maintain a node attribute.

The node attribute is called pingd by default, but is customizable in order to allow multiple ping groups to be defined.

Normally, the ping resource should run on all cluster nodes, which means that you’ll need to create a clone. A template for this can be found below, along with a description of the most interesting parameters.

Commonly Used ocf:pacemaker:ping Resource Parameters

Resource Parameter	Description
dampen	The time to wait (dampening) for further changes to occur. Use this to prevent a resource from bouncing around the cluster when cluster nodes notice the loss of connectivity at slightly different times.
multiplier	The number of connected ping nodes gets multiplied by this value to get a score. Useful when there are multiple ping nodes configured.
host_list	The machines to contact in order to determine the current connectivity status. Allowed values include resolvable DNS connectivity host names, IPv4 addresses, and IPv6 addresses.

Example ping resource that checks node connectivity once every minute

<clone id="Connected">
   <primitive id="ping" class="ocf" provider="pacemaker" type="ping">
    <instance_attributes id="ping-attrs">
      <nvpair id="ping-dampen"     name="dampen" value="5s"/>
      <nvpair id="ping-multiplier" name="multiplier" value="1000"/>
      <nvpair id="ping-hosts"      name="host_list" value="my.gateway.com www.bigcorp.com"/>
    </instance_attributes>
    <operations>
      <op id="ping-monitor-60s" interval="60s" name="monitor"/>
    </operations>
   </primitive>
</clone>

Important

You’re only half done. The next section deals with telling Pacemaker how to deal with the connectivity status that ocf:pacemaker:ping is recording.

8.2.2. Tell Pacemaker How to Interpret the Connectivity Data

Important

Before attempting the following, make sure you understand rules. See the “Rules” chapter of the Pacemaker Explained document for details.

There are a number of ways to use the connectivity data.

The most common setup is for people to have a single ping target (for example, the service network’s default gateway), to prevent the cluster from running a resource on any unconnected node.

Don’t run a resource on unconnected nodes

<rsc_location id="WebServer-no-connectivity" rsc="Webserver">
   <rule id="ping-exclude-rule" score="-INFINITY" >
      <expression id="ping-exclude" attribute="pingd" operation="not_defined"/>
   </rule>
</rsc_location>

A more complex setup is to have a number of ping targets configured. You can require the cluster to only run resources on nodes that can connect to all (or a minimum subset) of them.

Run only on nodes connected to three or more ping targets

<primitive id="ping" provider="pacemaker" class="ocf" type="ping">
... <!-- omitting some configuration to highlight important parts -->
   <nvpair id="ping-multiplier" name="multiplier" value="1000"/>
...
</primitive>
...
<rsc_location id="WebServer-connectivity" rsc="Webserver">
   <rule id="ping-prefer-rule" score="-INFINITY" >
      <expression id="ping-prefer" attribute="pingd" operation="lt" value="3000"/>
   </rule>
</rsc_location>

Alternatively, you can tell the cluster only to prefer nodes with the best connectivity, by using score-attribute in the rule. Just be sure to set multiplier to a value higher than that of resource-stickiness (and don’t set either of them to INFINITY).

Prefer node with most connected ping nodes

<rsc_location id="WebServer-connectivity" rsc="Webserver">
   <rule id="ping-prefer-rule" score-attribute="pingd" >
      <expression id="ping-prefer" attribute="pingd" operation="defined"/>
   </rule>
</rsc_location>

It is perhaps easier to think of this in terms of the simple constraints that the cluster translates it into. For example, if sles-1 is connected to all five ping nodes but sles-2 is only connected to two, then it would be as if you instead had the following constraints in your configuration:

How the cluster translates the above location constraint

<rsc_location id="ping-1" rsc="Webserver" node="sles-1" score="5000"/>
<rsc_location id="ping-2" rsc="Webserver" node="sles-2" score="2000"/>

The advantage is that you don’t have to manually update any constraints whenever your network connectivity changes.

You can also combine the concepts above into something even more complex. The example below shows how you can prefer the node with the most connected ping nodes provided they have connectivity to at least three (again assuming that multiplier is set to 1000).

More complex example of choosing location based on connectivity

<rsc_location id="WebServer-connectivity" rsc="Webserver">
   <rule id="ping-exclude-rule" score="-INFINITY" >
      <expression id="ping-exclude" attribute="pingd" operation="lt" value="3000"/>
   </rule>
   <rule id="ping-prefer-rule" score-attribute="pingd" >
      <expression id="ping-prefer" attribute="pingd" operation="defined"/>
   </rule>
</rsc_location>

9. Troubleshooting Cluster Problems

9.1. Logging

Pacemaker by default logs messages of notice severity and higher to the system log, and messages of info severity and higher to the detail log, which by default is /var/log/pacemaker/pacemaker.log.

Logging options can be controlled via environment variables at Pacemaker start-up. Where these are set varies by operating system (often /etc/sysconfig/pacemaker or /etc/default/pacemaker). See the comments in that file for details.

Because cluster problems are often highly complex, involving multiple machines, cluster daemons, and managed services, Pacemaker logs rather verbosely to provide as much context as possible. It is an ongoing priority to make these logs more user-friendly, but by necessity there is a lot of obscure, low-level information that can make them difficult to follow.

The default log rotation configuration shipped with Pacemaker (typically installed in /etc/logrotate.d/pacemaker) rotates the log when it reaches 100MB in size, or weekly, whichever comes first.

If you configure debug or (Heaven forbid) trace-level logging, the logs can grow enormous quite quickly. Because rotated logs are by default named with the year, month, and day only, this can cause name collisions if your logs exceed 100MB in a single day. You can add dateformat -%Y%m%d-%H to the rotation configuration to avoid this.

9.2. Reading the Logs

When troubleshooting, first check the system log or journal for errors or warnings from Pacemaker components (conveniently, they will all have “pacemaker” in their logged process name). For example:

# grep 'pacemaker.*\(error\|warning\)' /var/log/messages
Mar 29 14:04:19 node1 pacemaker-controld[86636]: error: Result of monitor operation for rn2 on node1: Timed Out after 45s (Remote executor did not respond)

If that doesn’t give sufficient information, next look at the notice level messages from pacemaker-controld. These will show changes in the state of cluster nodes. On the DC, this will also show resource actions attempted. For example:

# grep 'pacemaker-controld.*notice:' /var/log/messages
... output skipped for brevity ...
Mar 29 14:05:36 node1 pacemaker-controld[86636]: notice: Node rn2 state is now lost
... more output skipped for brevity ...
Mar 29 14:12:17 node1 pacemaker-controld[86636]: notice: Initiating stop operation rsc1_stop_0 on node4
... more output skipped for brevity ...

Of course, you can use other tools besides grep to search the logs.

9.3. Transitions

A key concept in understanding how a Pacemaker cluster functions is a transition. A transition is a set of actions that need to be taken to bring the cluster from its current state to the desired state (as expressed by the configuration).

Whenever a relevant event happens (a node joining or leaving the cluster, a resource failing, etc.), the controller will ask the scheduler to recalculate the status of the cluster, which generates a new transition. The controller then performs the actions in the transition in the proper order.

Each transition can be identified in the DC’s logs by a line like:

notice: Calculated transition 19, saving inputs in /var/lib/pacemaker/pengine/pe-input-1463.bz2

The file listed as the “inputs” is a snapshot of the cluster configuration and state at that moment (the CIB). This file can help determine why particular actions were scheduled. The crm_simulate command, described in Simulate Cluster Activity with crm_simulate, can be used to replay the file.

The log messages immediately before the “saving inputs” message will include any actions that the scheduler thinks need to be done.

9.4. Node Failures

When a node fails, and looking at errors and warnings doesn’t give an obvious explanation, try to answer questions like the following based on log messages:

• When and what was the last successful message on the node itself, or about that node in the other nodes’ logs?
• Did pacemaker-controld on the other nodes notice the node leave?
• Did pacemaker-controld on the DC invoke the scheduler and schedule a new transition?
• Did the transition include fencing the failed node?
• Was fencing attempted?
• Did fencing succeed?

9.5. Resource Failures

When a resource fails, and looking at errors and warnings doesn’t give an obvious explanation, try to answer questions like the following based on log messages:

• Did pacemaker-controld record the result of the failed resource action?
• What was the failed action’s execution status and exit status?
• What code in the resource agent could result in those status codes?
• Did pacemaker-controld on the DC invoke the scheduler and schedule a new transition?
• Did the new transition include recovery of the resource?
• Were the recovery actions initiated, and what were their results?

10. Upgrading a Pacemaker Cluster

10.1. Pacemaker Versioning

Pacemaker has an overall release version, plus separate version numbers for certain internal components.

• Pacemaker release version: This version consists of three numbers (x.y.z).

  The major version number (the x in x.y.z) increases when at least some rolling upgrades are not possible from the previous major version. For example, a rolling upgrade from 1.0.8 to 1.1.15 should always be supported, but a rolling upgrade from 1.0.8 to 2.0.0 may not be possible.

  The minor version (the y in x.y.z) increases when there are significant changes in cluster default behavior, tool behavior, and/or the API interface (for software that utilizes Pacemaker libraries). The main benefit is to alert you to pay closer attention to the release notes, to see if you might be affected.

  The release counter (the z in x.y.z) is increased with all public releases of Pacemaker, which typically include both bug fixes and new features.

• CRM feature set: This version number applies to the communication between full cluster nodes, and is used to avoid problems in mixed-version clusters.

  The major version number increases when nodes with different versions would not work (rolling upgrades are not allowed). The minor version number increases when mixed-version clusters are allowed only during rolling upgrades. The minor-minor version number is ignored, but allows resource agents to detect cluster support for various features. [1]

  Pacemaker ensures that the longest-running node is the cluster’s DC. This ensures new features are not enabled until all nodes are upgraded to support them.

• Pacemaker Remote protocol version: This version applies to communication between a Pacemaker Remote node and the cluster. It increases when an older cluster node would have problems hosting the connection to a newer Pacemaker Remote node. To avoid these problems, Pacemaker Remote nodes will accept connections only from cluster nodes with the same or newer Pacemaker Remote protocol version.

  Unlike with CRM feature set differences between full cluster nodes, mixed Pacemaker Remote protocol versions between Pacemaker Remote nodes and full cluster nodes are fine, as long as the Pacemaker Remote nodes have the older version. This can be useful, for example, to host a legacy application in an older operating system version used as a Pacemaker Remote node.

• XML schema version: Pacemaker’s configuration syntax — what’s allowed in the Configuration Information Base (CIB) — has its own version. This allows the configuration syntax to evolve over time while still allowing clusters with older configurations to work without change.

10.2. Upgrading Cluster Software

There are three approaches to upgrading a cluster, each with advantages and disadvantages.

Upgrade Methods

Method	Available between all versions	Can be used with Pacemaker Remote nodes	Service outage during upgrade	Service recovery during upgrade	Exercises failover logic	Allows change of messaging layer [2]
Complete cluster shutdown	yes	yes	always	N/A	no	yes
Rolling (node by node)	no	yes	always [3]	yes	yes	no
Detach and reattach	yes	no	only due to failure	no	no	yes

10.2.1. Complete Cluster Shutdown

In this scenario, one shuts down all cluster nodes and resources, then upgrades all the nodes before restarting the cluster.

1. On each node:
   1. Shutdown the cluster software (pacemaker and the messaging layer).
   2. Upgrade the Pacemaker software. This may also include upgrading the messaging layer and/or the underlying operating system.
   3. Check the configuration with the crm_verify tool.
2. On each node:
   1. Start the cluster software.

Currently, only Corosync version 2 and greater is supported as the cluster layer, but if another stack is supported in the future, the stack does not need to be the same one before the upgrade.

One variation of this approach is to build a new cluster on new hosts. This allows the new version to be tested beforehand, and minimizes downtime by having the new nodes ready to be placed in production as soon as the old nodes are shut down.

10.2.2. Rolling (node by node)

In this scenario, each node is removed from the cluster, upgraded, and then brought back online, until all nodes are running the newest version.

Special considerations when planning a rolling upgrade:

• If you plan to upgrade other cluster software – such as the messaging layer – at the same time, consult that software’s documentation for its compatibility with a rolling upgrade.
• If the major version number is changing in the Pacemaker version you are upgrading to, a rolling upgrade may not be possible. Read the new version’s release notes (as well the information here) for what limitations may exist.
• If the CRM feature set is changing in the Pacemaker version you are upgrading to, you should run a mixed-version cluster only during a small rolling upgrade window. If one of the older nodes drops out of the cluster for any reason, it will not be able to rejoin until it is upgraded.
• If the Pacemaker Remote protocol version is changing, all cluster nodes should be upgraded before upgrading any Pacemaker Remote nodes.

See the Pacemaker release calendar on the ClusterLabs wiki to figure out whether the CRM feature set and/or Pacemaker Remote protocol version changed between the Pacemaker release versions in your rolling upgrade.

To perform a rolling upgrade, on each node in turn:

1. Put the node into standby mode, and wait for any active resources to be moved cleanly to another node. (This step is optional, but allows you to deal with any resource issues before the upgrade.)
2. Shutdown the cluster software (pacemaker and the messaging layer) on the node.
3. Upgrade the Pacemaker software. This may also include upgrading the messaging layer and/or the underlying operating system.
4. If this is the first node to be upgraded, check the configuration with the crm_verify tool.
5. Start the messaging layer. This must be the same messaging layer (currently only Corosync version 2 and greater is supported) that the rest of the cluster is using.

Note

Even if a rolling upgrade from the current version of the cluster to the newest version is not directly possible, it may be possible to perform a rolling upgrade in multiple steps, by upgrading to an intermediate version first.

Version Compatibility Table

Version being Installed	Oldest Compatible Version
Pacemaker 2.y.z	Pacemaker 1.1.11 [4]
Pacemaker 1.y.z	Pacemaker 1.0.0
Pacemaker 0.7.z	Pacemaker 0.6.z

10.2.3. Detach and Reattach

The reattach method is a variant of a complete cluster shutdown, where the resources are left active and get re-detected when the cluster is restarted.

This method may not be used if the cluster contains any Pacemaker Remote nodes.

1. Tell the cluster to stop managing services. This is required to allow the services to remain active after the cluster shuts down.

   # crm_attribute --name maintenance-mode --update true
   

2. On each node, shutdown the cluster software (pacemaker and the messaging layer), and upgrade the Pacemaker software. This may also include upgrading the messaging layer. While the underlying operating system may be upgraded at the same time, that will be more likely to cause outages in the detached services (certainly, if a reboot is required).

3. Check the configuration with the crm_verify tool.

4. On each node, start the cluster software. Currently, only Corosync version 2 and greater is supported as the cluster layer, but if another stack is supported in the future, the stack does not need to be the same one before the upgrade.

5. Verify that the cluster re-detected all resources correctly.

6. Allow the cluster to resume managing resources again:

   # crm_attribute --name maintenance-mode --delete
   

Note

While the goal of the detach-and-reattach method is to avoid disturbing running services, resources may still move after the upgrade if any resource’s location is governed by a rule based on transient node attributes. Transient node attributes are erased when the node leaves the cluster. A common example is using the ocf:pacemaker:ping resource to set a node attribute used to locate other resources.

10.3. Upgrading the Configuration

The CIB schema version can change from one Pacemaker version to another.

After cluster software is upgraded, the cluster will continue to use the older schema version that it was previously using. This can be useful, for example, when administrators have written tools that modify the configuration, and are based on the older syntax. [5]

However, when using an older syntax, new features may be unavailable, and there is a performance impact, since the cluster must do a non-persistent configuration upgrade before each transition. So while using the old syntax is possible, it is not advisable to continue using it indefinitely.

Even if you wish to continue using the old syntax, it is a good idea to follow the upgrade procedure outlined below, except for the last step, to ensure that the new software has no problems with your existing configuration (since it will perform much the same task internally).

If you are brave, it is sufficient simply to run cibadmin --upgrade.

A more cautious approach would proceed like this:

1. Create a shadow copy of the configuration. The later commands will automatically operate on this copy, rather than the live configuration.

   # crm_shadow --create shadow
   

1. Verify the configuration is valid with the new software (which may be stricter about syntax mistakes, or may have dropped support for deprecated features):

   # crm_verify --live-check
   

2. Fix any errors or warnings.

3. Perform the upgrade:

   # cibadmin --upgrade
   

4. If this step fails, there are three main possibilities:

   1. The configuration was not valid to start with (did you do steps 2 and 3?).
   2. The transformation failed; report a bug.
   3. The transformation was successful but produced an invalid result.

   If the result of the transformation is invalid, you may see a number of errors from the validation library. If these are not helpful, try the manual upgrade procedure described below.

5. Check the changes:

   # crm_shadow --diff
   

   If at this point there is anything about the upgrade that you wish to fine-tune (for example, to change some of the automatic IDs), now is the time to do so:

   # crm_shadow --edit
   

   This will open the configuration in your favorite editor (whichever is specified by the standard $EDITOR environment variable).

6. Preview how the cluster will react:

   # crm_simulate --live-check --save-dotfile shadow.dot -S
   # dot -Tsvg shadow.dot -o shadow.svg
   

   You can then view shadow.svg with any compatible image viewer or web browser. Verify that either no resource actions will occur or that you are happy with any that are scheduled. If the output contains actions you do not expect (possibly due to changes to the score calculations), you may need to make further manual changes. See Simulate Cluster Activity with crm_simulate for further details on how to interpret the output of crm_simulate and dot.

7. Upload the changes:

   # crm_shadow --commit shadow --force
   

   In the unlikely event this step fails, please report a bug.

Note

It is also possible to perform the configuration upgrade steps manually:

1. Locate the upgrade*.xsl conversion scripts provided with the source code. These will often be installed in a location such as /usr/share/pacemaker, or may be obtained from the source repository.

2. Run the conversion scripts that apply to your older version, for example:

   # xsltproc /path/to/upgrade06.xsl config06.xml > config10.xml
   

3. Locate the pacemaker.rng script (from the same location as the xsl files).

4. Check the XML validity:

   # xmllint --relaxng /path/to/pacemaker.rng config10.xml
   

The advantage of this method is that it can be performed without the cluster running, and any validation errors are often more informative.

10.4. What Changed in 2.1

The Pacemaker 2.1 release is fully backward-compatible in both the CIB XML and the C API. Highlights:

• Pacemaker now supports the OCF Resource Agent API version 1.1. Most notably, the Master and Slave role names have been renamed to Promoted and Unpromoted.
• Pacemaker now supports colocations where the dependent resource does not affect the primary resource’s placement (via a new influence colocation constraint option and critical resource meta-attribute). This is intended for cases where a less-important resource must be colocated with an essential resource, but it is preferred to leave the less-important resource stopped if it fails, rather than move both resources.
• If Pacemaker is built with libqb 2.0 or later, the detail log will use millisecond-resolution timestamps.
• In addition to crm_mon and stonith_admin, the crmadmin, crm_resource, crm_simulate, and crm_verify commands now support the --output-as and --output-to options, including XML output (which scripts and higher-level tools are strongly recommended to use instead of trying to parse the text output, which may change from release to release).

For a detailed list of changes, see the release notes and Pacemaker 2.1 Changes on the ClusterLabs wiki.

10.5. What Changed in 2.0

The main goal of the 2.0 release was to remove support for deprecated syntax, along with some small changes in default configuration behavior and tool behavior. Highlights:

• Only Corosync version 2 and greater is now supported as the underlying cluster layer. Support for Heartbeat and Corosync 1 (including CMAN) is removed.
• The Pacemaker detail log file is now stored in /var/log/pacemaker/pacemaker.log by default.
• The record-pending cluster property now defaults to true, which allows status tools such as crm_mon to show operations that are in progress.
• Support for a number of deprecated build options, environment variables, and configuration settings has been removed.
• The master tag has been deprecated in favor of using the clone tag with the new promotable meta-attribute set to true. “Master/slave” clone resources are now referred to as “promotable” clone resources.
• The public API for Pacemaker libraries that software applications can use has changed significantly.

For a detailed list of changes, see the release notes and Pacemaker 2.0 Changes on the ClusterLabs wiki.

10.6. What Changed in 1.0

10.6.1. New

• Failure timeouts.
• New section for resource and operation defaults.
• Tool for making offline configuration changes.
• Rules, instance_attributes, meta_attributes and sets of operations can be defined once and referenced in multiple places.
• The CIB now accepts XPath-based create/modify/delete operations. See cibadmin --help.
• Multi-dimensional colocation and ordering constraints.
• The ability to connect to the CIB from non-cluster machines.
• Allow recurring actions to be triggered at known times.

10.6.2. Changed

• Syntax

  • All resource and cluster options now use dashes (-) instead of underscores (_)
  • master_slave was renamed to master
  • The attributes container tag was removed
  • The operation field pre-req has been renamed requires
  • All operations must have an interval, start/stop must have it set to zero

• The stonith-enabled option now defaults to true.

• The cluster will refuse to start resources if stonith-enabled is true (or unset) and no STONITH resources have been defined

• The attributes of colocation and ordering constraints were renamed for clarity.

• resource-failure-stickiness has been replaced by migration-threshold.

• The parameters for command-line tools have been made consistent

• Switched to ‘RelaxNG’ schema validation and ‘libxml2’ parser

  • id fields are now XML IDs which have the following limitations:

    • id’s cannot contain colons (:)
    • id’s cannot begin with a number
    • id’s must be globally unique (not just unique for that tag)

  • Some fields (such as those in constraints that refer to resources) are IDREFs.

    This means that they must reference existing resources or objects in order for the configuration to be valid. Removing an object which is referenced elsewhere will therefore fail.

  • The CIB representation, from which a MD5 digest is calculated to verify CIBs on the nodes, has changed.

    This means that every CIB update will require a full refresh on any upgraded nodes until the cluster is fully upgraded to 1.0. This will result in significant performance degradation and it is therefore highly inadvisable to run a mixed 1.0/0.6 cluster for any longer than absolutely necessary.

• Ping node information no longer needs to be added to ha.cf. Simply include the lists of hosts in your ping resource(s).

10.6.3. Removed

• Syntax
  • It is no longer possible to set resource meta options as top-level attributes. Use meta-attributes instead.
  • Resource and operation defaults are no longer read from crm_config.

Footnotes

[1]	Before CRM feature set 3.1.0 (Pacemaker 2.0.0), the minor-minor version number was treated the same as the minor version.

[2]	Currently, Corosync version 2 and greater is the only supported cluster stack, but other stacks have been supported by past versions, and may be supported by future versions.

[3]	Any active resources will be moved off the node being upgraded, so there will be at least a brief outage unless all resources can be migrated “live”.

[4]	Rolling upgrades from Pacemaker 1.1.z to 2.y.z are possible only if the cluster uses corosync version 2 or greater as its messaging layer, and the Cluster Information Base (CIB) uses schema 1.0 or higher in its validate-with property.

[5]	As of Pacemaker 2.0.0, only schema versions pacemaker-1.0 and higher are supported (excluding pacemaker-1.1, which was a special case).

11. Alert Agents

11.1. Using the Sample Alert Agents

Pacemaker provides several sample alert agents, installed in /usr/share/pacemaker/alerts by default.

While these sample scripts may be copied and used as-is, they are provided mainly as templates to be edited to suit your purposes. See their source code for the full set of instance attributes they support.

Sending cluster events as SNMP v2c traps

<configuration>
   <alerts>
      <alert id="snmp_alert" path="/path/to/alert_snmp.sh">
         <instance_attributes id="config_for_alert_snmp">
            <nvpair id="trap_node_states" name="trap_node_states"
                    value="all"/>
         </instance_attributes>
         <meta_attributes id="config_for_timestamp">
            <nvpair id="ts_fmt" name="timestamp-format"
                    value="%Y-%m-%d,%H:%M:%S.%01N"/>
         </meta_attributes>
         <recipient id="snmp_destination" value="192.168.1.2"/>
      </alert>
   </alerts>
</configuration>

Note

SNMP alert agent attributes

The timestamp-format meta-attribute should always be set to %Y-%m-%d,%H:%M:%S.%01N when using the SNMP agent, to match the SNMP standard.

The SNMP agent provides a number of instance attributes in addition to the one used in the example above. The most useful are trap_version, which defaults to 2c, and trap_community, which defaults to public. See the source code for more details.

Sending cluster events as SNMP v3 traps

<configuration>
   <alerts>
      <alert id="snmp_alert" path="/path/to/alert_snmp.sh">
         <instance_attributes id="config_for_alert_snmp">
            <nvpair id="trap_node_states" name="trap_node_states"
                    value="all"/>
            <nvpair id="trap_version" name="trap_version" value="3"/>
            <nvpair id="trap_community" name="trap_community" value=""/>
            <nvpair id="trap_options" name="trap_options"
                    value="-l authNoPriv -a MD5 -u testuser -A secret1"/>
         </instance_attributes>
         <meta_attributes id="config_for_timestamp">
            <nvpair id="ts_fmt" name="timestamp-format"
                    value="%Y-%m-%d,%H:%M:%S.%01N"/>
         </meta_attributes>
         <recipient id="snmp_destination" value="192.168.1.2"/>
      </alert>
   </alerts>
</configuration>

Note

SNMP v3 trap configuration

To use SNMP v3, trap_version must be set to 3. trap_community will be ignored.

The example above uses the trap_options instance attribute to override the security level, authentication protocol, authentication user, and authentication password from snmp.conf. These will be passed to the snmptrap command. Passing the password on the command line is considered insecure; specify authentication and privacy options suitable for your environment.

Sending cluster events as e-mails

<configuration>
   <alerts>
      <alert id="smtp_alert" path="/path/to/alert_smtp.sh">
         <instance_attributes id="config_for_alert_smtp">
            <nvpair id="email_sender" name="email_sender"
                    value="donotreply@example.com"/>
         </instance_attributes>
         <recipient id="smtp_destination" value="admin@example.com"/>
      </alert>
   </alerts>
</configuration>

11.2. Writing an Alert Agent

Environment variables passed to alert agents

Environment Variable	Description
CRM_alert_kind	The type of alert (node, fencing, resource, or attribute)
CRM_alert_node	Name of affected node
CRM_alert_node_sequence	A sequence number increased whenever an alert is being issued on the local node, which can be used to reference the order in which alerts have been issued by Pacemaker. An alert for an event that happened later in time reliably has a higher sequence number than alerts for earlier events. Be aware that this number has no cluster-wide meaning.
CRM_alert_recipient	The configured recipient
CRM_alert_timestamp	A timestamp created prior to executing the agent, in the format specified by the timestamp-format meta-attribute. This allows the agent to have a reliable, high-precision time of when the event occurred, regardless of when the agent itself was invoked (which could potentially be delayed due to system load, etc.).
CRM_alert_timestamp_epoch	The same time as CRM_alert_timestamp, expressed as the integer number of seconds since January 1, 1970. This (along with CRM_alert_timestamp_usec) can be useful for alert agents that need to format time in a specific way rather than let the user configure it.
CRM_alert_timestamp_usec	The same time as CRM_alert_timestamp, expressed as the integer number of microseconds since CRM_alert_timestamp_epoch.
CRM_alert_version	The version of Pacemaker sending the alert
CRM_alert_desc	Detail about event. For node alerts, this is the node’s current state (member or lost). For fencing alerts, this is a summary of the requested fencing operation, including origin, target, and fencing operation error code, if any. For resource alerts, this is a readable string equivalent of CRM_alert_status.
CRM_alert_nodeid	ID of node whose status changed (provided with node alerts only)
CRM_alert_rc	The numerical return code of the fencing or resource operation (provided with fencing and resource alerts only)
CRM_alert_task	The requested fencing or resource operation (provided with fencing and resource alerts only)
CRM_alert_exec_time	The (wall-clock) time, in milliseconds, that it took to execute the action. If the action timed out, CRM_alert_status will be 2, CRM_alert_desc will be “Timed Out”, and this value will be the action timeout. May not be supported on all platforms. (resource alerts only) (since 2.0.1)
CRM_alert_interval	The interval of the resource operation (resource alerts only)
CRM_alert_rsc	The name of the affected resource (resource alerts only)
CRM_alert_status	A numerical code used by Pacemaker to represent the operation result (resource alerts only)
CRM_alert_target_rc	The expected numerical return code of the operation (resource alerts only)
CRM_alert_attribute_name	The name of the node attribute that changed (attribute alerts only)
CRM_alert_attribute_value	The new value of the node attribute that changed (attribute alerts only)

Special concerns when writing alert agents:

• Alert agents may be called with no recipient (if none is configured), so the agent must be able to handle this situation, even if it only exits in that case. (Users may modify the configuration in stages, and add a recipient later.)
• If more than one recipient is configured for an alert, the alert agent will be called once per recipient. If an agent is not able to run concurrently, it should be configured with only a single recipient. The agent is free, however, to interpret the recipient as a list.
• When a cluster event occurs, all alerts are fired off at the same time as separate processes. Depending on how many alerts and recipients are configured, and on what is done within the alert agents, a significant load burst may occur. The agent could be written to take this into consideration, for example by queueing resource-intensive actions into some other instance, instead of directly executing them.
• Alert agents are run as the hacluster user, which has a minimal set of permissions. If an agent requires additional privileges, it is recommended to configure sudo to allow the agent to run the necessary commands as another user with the appropriate privileges.
• As always, take care to validate and sanitize user-configured parameters, such as CRM_alert_timestamp (whose content is specified by the user-configured timestamp-format), CRM_alert_recipient, and all instance attributes. Mostly this is needed simply to protect against configuration errors, but if some user can modify the CIB without having hacluster access to the cluster nodes, it is a potential security concern as well, to avoid the possibility of code injection.

Note

ocf:pacemaker:ClusterMon compatibility

The alerts interface is designed to be backward compatible with the external scripts interface used by the ocf:pacemaker:ClusterMon resource, which is now deprecated. To preserve this compatibility, the environment variables passed to alert agents are available prepended with CRM_notify_ as well as CRM_alert_. One break in compatibility is that ClusterMon ran external scripts as the root user, while alert agents are run as the hacluster user.

12. Resource Agents

12.1. Action Completion

If one resource depends on another resource via constraints, the cluster will interpret an expected result as sufficient to continue with dependent actions. This may cause timing issues if the resource agent start returns before the service is not only launched but fully ready to perform its function, or if the resource agent stop returns before the service has fully released all its claims on system resources. At a minimum, the start or stop should not return before a status command would return the expected (started or stopped) result.

12.2. OCF Resource Agents

12.2.1. Location of Custom Scripts

OCF Resource Agents are found in /usr/lib/ocf/resource.d/$PROVIDER

When creating your own agents, you are encouraged to create a new directory under /usr/lib/ocf/resource.d/ so that they are not confused with (or overwritten by) the agents shipped by existing providers.

So, for example, if you choose the provider name of big-corp and want a new resource named big-app, you would create a resource agent called /usr/lib/ocf/resource.d/big-corp/big-app and define a resource:

12.2.2. Actions

All OCF resource agents are required to implement the following actions.

Required Actions for OCF Agents

Action	Description	Instructions
start	Start the resource	Return OCF_SUCCESS on success and an appropriate error code otherwise. Must not report success until the resource is fully active.
stop	Stop the resource	Return OCF_SUCCESS on success and an appropriate error code otherwise. Must not report success until the resource is fully stopped.
monitor	Check the resource’s state	Return OCF_SUCCESS if the resource is running, OCF_NOT_RUNNING if it is stopped, and any other OCF exit code if it is failed. Note: The monitor action should test the state of the resource on the local machine only.
meta-data	Describe the resource	Provide information about this resource in the XML format defined by the OCF standard. Return OCF_SUCCESS. Note: This is not required to be performed as root.

OCF resource agents may optionally implement additional actions. Some are used only with advanced resource types such as clones.

Optional Actions for OCF Resource Agents

Action	Description	Instructions
validate-all	Validate the instance parameters provided.	Return OCF_SUCCESS if parameters are valid, OCF_ERR_ARGS if not valid, and OCF_ERR_CONFIGURED if resource is not configured.
promote	Bring the local instance of a promotable clone resource to the promoted role.	Return OCF_SUCCESS on success.
demote	Bring the local instance of a promotable clone resource to the unpromoted role.	Return OCF_SUCCESS on success.
notify	Used by the cluster to send the agent pre- and post-notification events telling the resource what has happened and what will happen.	Must not fail. Must return OCF_SUCCESS.
reload	Reload the service’s own configuration.	Not used by Pacemaker.
reload-agent	Make effective any changes in instance parameters marked as reloadable in the agent’s meta-data.	This is used when the agent can handle a change in some of its parameters more efficiently than stopping and starting the resource.
recover	Restart the service.	Not used by Pacemaker.

Important

If you create a new OCF resource agent, use ocf-tester to verify that the agent complies with the OCF standard properly.

12.2.3. How Are OCF Return Codes Interpreted?

The first thing the cluster does is to check the return code against the expected result. If the result does not match the expected value, then the operation is considered to have failed, and recovery action is initiated.

There are three types of failure recovery:

Types of Recovery Performed by the Cluster

Type	Description	Action Taken by the Cluster
soft	A transient error	Restart the resource or move it to a new location
hard	A non-transient error that may be specific to the current node	Move the resource elsewhere and prevent it from being retried on the current node
fatal	A non-transient error that will be common to all cluster nodes (for example, a bad configuration was specified)	Stop the resource and prevent it from being started on any cluster node

12.2.4. OCF Return Codes

The following table outlines the various OCF return codes and the type of recovery the cluster will initiate when a failure code is received. Although counterintuitive, even actions that return OCF_SUCCESS can be considered to have failed, if OCF_SUCCESS was not the expected return value.

OCF Exit Codes and Their Recovery Types

Exit Code	OCF Alias	Description	Recovery
0	OCF_SUCCESS	Success. The command completed successfully. This is the expected result for all start, stop, promote, and demote actions.	soft
1	OCF_ERR_GENERIC	Generic “there was a problem” error code.	hard
2	OCF_ERR_ARGS	The resource’s parameter values are not valid on this machine (for example, a value refers to a file not found on the local host).	hard
3	OCF_ERR_UNIMPLEMENTED	The requested action is not implemented.	hard
4	OCF_ERR_PERM	The resource agent does not have sufficient privileges to complete the task.	hard
5	OCF_ERR_INSTALLED	The tools required by the resource are not installed on this machine.	hard
6	OCF_ERR_CONFIGURED	The resource’s parameter values are inherently invalid (for example, a required parameter was not given).	fatal
7	OCF_NOT_RUNNING	The resource is safely stopped. This should only be returned by monitor actions, not stop actions.	N/A
8	OCF_RUNNING_PROMOTED	The resource is running in the promoted role.	soft
9	OCF_FAILED_PROMOTED	The resource is (or might be) in the promoted role but has failed. The resource will be demoted, stopped, and then started (and possibly promoted) again.	soft
190	OCF_DEGRADED	The resource is properly active, but in such a condition that future failures are more likely.	none
191	OCF_DEGRADED_PROMOTED	The resource is properly active in the promoted role, but in such a condition that future failures are more likely.	none
other	none	Custom error code.	soft

Exceptions to the recovery handling described above:

• Probes (non-recurring monitor actions) that find a resource active (or in the promoted role) will not result in recovery action unless it is also found active elsewhere.
• The recovery action taken when a resource is found active more than once is determined by the resource’s multiple-active property.
• Recurring actions that return OCF_ERR_UNIMPLEMENTED do not cause any type of recovery.
• Actions that return one of the “degraded” codes will be treated the same as if they had returned success, but status output will indicate that the resource is degraded.

12.2.5. Environment Variables

Pacemaker sets certain environment variables when it executes an OCF resource agent. Agents can check these variables to get information about resource parameters or the execution environment.

Note: Pacemaker may set other environment variables for its own purposes. They may be present in the agent’s environment, but Pacemaker is not providing them for the agent’s use, and so the agent should not rely on any variables not listed in the table below.

OCF Environment Variables

Environment Variable	Description
OCF_CHECK_LEVEL	Requested intensity level of checks in monitor and validate-all actions. Usually set as an operation attribute; see Pacemaker Explained for an example.
OCF_EXIT_REASON_PREFIX	Prefix for printing fatal error messages from the resource agent.
OCF_RA_VERSION_MAJOR	Major version number of the OCF Resource Agent API. If the script does not support this revision, it should report an error. See the OCF specification for an explanation of the versioning scheme used. The version number is split into two numbers for ease of use in shell scripts. These two may be used by the agent to determine whether it is run under an OCF-compliant resource manager.
OCF_RA_VERSION_MINOR	Minor version number of the OCF Resource Agent API. See OCF_RA_VERSION_MAJOR for more details.
OCF_RESKEY_crm_feature_set	crm_feature_set on the DC (or on the local node, if the agent is run by crm_resource).
OCF_RESKEY_CRM_meta_interval	Interval (in milliseconds) of the current operation.
OCF_RESKEY_CRM_meta_name	Name of the current operation.
OCF_RESKEY_CRM_meta_notify_*	See Clone Notifications.
OCF_RESKEY_CRM_meta_on_node	Name of the node where the current operation is running.
OCF_RESKEY_CRM_meta_on_node_uuid	Cluster-layer ID of the node where the current operation is running (or node name for Pacemaker Remote nodes).
OCF_RESKEY_CRM_meta_physical_host	If the node where the current operation is running is a guest node, the host on which the container is running.
OCF_RESKEY_CRM_meta_timeout	Timeout (in milliseconds) of the current operation.
OCF_RESKEY_CRM_meta_*	Each of a resource’s meta-attributes is converted to an environment variable prefixed with “OCF_RESKEY_CRM_meta_”. See Pacemaker Explained for some meta-attributes that have special meaning to Pacemaker.
OCF_RESKEY_*	Each of a resource’s instance parameters is converted to an environment variable prefixed with “OCF_RESKEY_”.
OCF_RESOURCE_INSTANCE	The name of the resource instance.
OCF_RESOURCE_PROVIDER	The name of the resource agent provider.
OCF_RESOURCE_TYPE	The name of the resource type.
OCF_ROOT	The root of the OCF directory hierarchy.
OCF_TRACE_FILE	The absolute path or file descriptor to write trace output to, if OCF_TRACE_RA is set to true. Pacemaker sets this only to /dev/stderr and only when running a resource agent via crm_resource.
OCF_TRACE_RA	If set to true, enable tracing of the resource agent. Trace output is written to OCF_TRACE_FILE if set; otherwise, it’s written to a file in OCF_RESKEY_trace_dir if set or in a default directory if not. Pacemaker sets this to true only when running a resource agent via crm_resource with one or more -V flags.
PCMK_DEBUGLOG (and HA_DEBUGLOG)	Where to write resource agent debug logs. Pacemaker sets this to PCMK_logfile if set to a value other than none and if debugging is enabled for the executor.
PCMK_LOGFACILITY (and HA_LOGFACILITY)	Syslog facility for resource agent logs. Pacemaker sets this to PCMK_logfacility if set to a value other than none or /dev/null.
PCMK_LOGFILE (and HA_LOGFILE)	Where to write resource agent logs. Pacemaker sets this to PCMK_logfile if set to a value other than none.
PCMK_service	The name of the Pacemaker subsystem or command-line tool that’s executing the resource agent. Specific values are subject to change; useful mainly for logging.

12.2.6. Clone Resource Agent Requirements

Any resource can be used as an anonymous clone, as it requires no additional support from the resource agent. Whether it makes sense to do so depends on your resource and its resource agent.

12.2.6.1. Resource Agent Requirements for Globally Unique Clones

Globally unique clones require additional support in the resource agent. In particular, it must respond with OCF_SUCCESS only if the node has that exact instance active. All other probes for instances of the clone should result in OCF_NOT_RUNNING (or one of the other OCF error codes if they are failed).

Individual instances of a clone are identified by appending a colon and a numerical offset (for example, apache:2).

A resource agent can find out how many copies there are by examining the OCF_RESKEY_CRM_meta_clone_max environment variable and which instance it is by examining OCF_RESKEY_CRM_meta_clone.

The resource agent must not make any assumptions (based on OCF_RESKEY_CRM_meta_clone) about which numerical instances are active. In particular, the list of active copies is not always an unbroken sequence, nor does it always start at 0.

12.2.6.2. Resource Agent Requirements for Promotable Clones

Promotable clone resources require two extra actions, demote and promote, which are responsible for changing the state of the resource. Like start and stop, they should return OCF_SUCCESS if they completed successfully or a relevant error code if they did not.

The states can mean whatever you wish, but when the resource is started, it must begin in the unpromoted role. From there, the cluster will decide which instances to promote.

In addition to the clone requirements for monitor actions, agents must also accurately report which state they are in. The cluster relies on the agent to report its status (including role) accurately and does not indicate to the agent what role it currently believes it to be in.

Role Implications of OCF Return Codes

Monitor Return Code	Description
OCF_NOT_RUNNING	Stopped
OCF_SUCCESS	Running (Unpromoted)
OCF_RUNNING_PROMOTED	Running (Promoted)
OCF_FAILED_PROMOTED	Failed (Promoted)
Other	Failed (Unpromoted)

12.2.6.3. Clone Notifications

If the clone has the notify meta-attribute set to true and the resource agent supports the notify action, Pacemaker will call the action when appropriate, passing a number of extra variables. These variables, when combined with additional context, can be used to calculate the current state of the cluster and what is about to happen to it.

Environment Variables Supplied with Clone Notify Actions

Variable	Description
OCF_RESKEY_CRM_meta_notify_type	Allowed values: pre, post
OCF_RESKEY_CRM_meta_notify_operation	Allowed values: start, stop
OCF_RESKEY_CRM_meta_notify_start_resource	Resources to be started
OCF_RESKEY_CRM_meta_notify_stop_resource	Resources to be stopped
OCF_RESKEY_CRM_meta_notify_active_resource	Resources that are running
OCF_RESKEY_CRM_meta_notify_inactive_resource	Resources that are not running
OCF_RESKEY_CRM_meta_notify_start_uname	Nodes on which resources will be started
OCF_RESKEY_CRM_meta_notify_stop_uname	Nodes on which resources will be stopped
OCF_RESKEY_CRM_meta_notify_active_uname	Nodes on which resources are running

The variables come in pairs, such as OCF_RESKEY_CRM_meta_notify_start_resource and OCF_RESKEY_CRM_meta_notify_start_uname, and should be treated as an array of whitespace-separated elements.

OCF_RESKEY_CRM_meta_notify_inactive_resource is an exception, as the matching uname variable does not exist since inactive resources are not running on any node.

Thus, in order to indicate that clone:0 will be started on sles-1, clone:2 will be started on sles-3, and clone:3 will be started on sles-2, the cluster would set:

Notification Variables

OCF_RESKEY_CRM_meta_notify_start_resource="clone:0 clone:2 clone:3"
OCF_RESKEY_CRM_meta_notify_start_uname="sles-1 sles-3 sles-2"

Note

Pacemaker will log but otherwise ignore failures of notify actions.

12.2.6.4. Interpretation of Notification Variables

Pre-notification (stop):

• Active resources: $OCF_RESKEY_CRM_meta_notify_active_resource
• Inactive resources: $OCF_RESKEY_CRM_meta_notify_inactive_resource
• Resources to be started: $OCF_RESKEY_CRM_meta_notify_start_resource
• Resources to be stopped: $OCF_RESKEY_CRM_meta_notify_stop_resource

Post-notification (stop) / Pre-notification (start):

• Active resources

  • $OCF_RESKEY_CRM_meta_notify_active_resource
  • minus $OCF_RESKEY_CRM_meta_notify_stop_resource

• Inactive resources

  • $OCF_RESKEY_CRM_meta_notify_inactive_resource
  • plus $OCF_RESKEY_CRM_meta_notify_stop_resource

• Resources that were started: $OCF_RESKEY_CRM_meta_notify_start_resource
• Resources that were stopped: $OCF_RESKEY_CRM_meta_notify_stop_resource

Post-notification (start):

• Active resources:

  • $OCF_RESKEY_CRM_meta_notify_active_resource
  • minus $OCF_RESKEY_CRM_meta_notify_stop_resource
  • plus $OCF_RESKEY_CRM_meta_notify_start_resource

• Inactive resources:

  • $OCF_RESKEY_CRM_meta_notify_inactive_resource
  • plus $OCF_RESKEY_CRM_meta_notify_stop_resource
  • minus $OCF_RESKEY_CRM_meta_notify_start_resource

• Resources that were started: $OCF_RESKEY_CRM_meta_notify_start_resource
• Resources that were stopped: $OCF_RESKEY_CRM_meta_notify_stop_resource

12.2.6.5. Extra Notifications for Promotable Clones

Extra Environment Variables Supplied for Promotable Clones

Variable	Description
OCF_RESKEY_CRM_meta_notify_promoted_resource	Resources that are running in the promoted role
OCF_RESKEY_CRM_meta_notify_unpromoted_resource	Resources that are running in the unpromoted role
OCF_RESKEY_CRM_meta_notify_promote_resource	Resources to be promoted
OCF_RESKEY_CRM_meta_notify_demote_resource	Resources to be demoted
OCF_RESKEY_CRM_meta_notify_promote_uname	Nodes on which resources will be promoted
OCF_RESKEY_CRM_meta_notify_demote_uname	Nodes on which resources will be demoted
OCF_RESKEY_CRM_meta_notify_promoted_uname	Nodes on which resources are running in the promoted role
OCF_RESKEY_CRM_meta_notify_unpromoted_uname	Nodes on which resources are running in the unpromoted role

12.2.6.6. Interpretation of Promotable Notification Variables

Pre-notification (demote):

• Active resources: $OCF_RESKEY_CRM_meta_notify_active_resource
• Promoted resources: $OCF_RESKEY_CRM_meta_notify_promoted_resource
• Unpromoted resources: $OCF_RESKEY_CRM_meta_notify_unpromoted_resource
• Inactive resources: $OCF_RESKEY_CRM_meta_notify_inactive_resource
• Resources to be started: $OCF_RESKEY_CRM_meta_notify_start_resource
• Resources to be promoted: $OCF_RESKEY_CRM_meta_notify_promote_resource
• Resources to be demoted: $OCF_RESKEY_CRM_meta_notify_demote_resource
• Resources to be stopped: $OCF_RESKEY_CRM_meta_notify_stop_resource

Post-notification (demote) / Pre-notification (stop):

• Active resources: $OCF_RESKEY_CRM_meta_notify_active_resource

• Promoted resources:

  • $OCF_RESKEY_CRM_meta_notify_promoted_resource
  • minus $OCF_RESKEY_CRM_meta_notify_demote_resource

• Unpromoted resources: $OCF_RESKEY_CRM_meta_notify_unpromoted_resource
• Inactive resources: $OCF_RESKEY_CRM_meta_notify_inactive_resource
• Resources to be started: $OCF_RESKEY_CRM_meta_notify_start_resource
• Resources to be promoted: $OCF_RESKEY_CRM_meta_notify_promote_resource
• Resources to be demoted: $OCF_RESKEY_CRM_meta_notify_demote_resource
• Resources to be stopped: $OCF_RESKEY_CRM_meta_notify_stop_resource
• Resources that were demoted: $OCF_RESKEY_CRM_meta_notify_demote_resource

Post-notification (stop) / Pre-notification (start)

• Active resources:

  • $OCF_RESKEY_CRM_meta_notify_active_resource
  • minus $OCF_RESKEY_CRM_meta_notify_stop_resource

• Promoted resources:

  • $OCF_RESKEY_CRM_meta_notify_promoted_resource
  • minus $OCF_RESKEY_CRM_meta_notify_demote_resource

• Unpromoted resources:

  • $OCF_RESKEY_CRM_meta_notify_unpromoted_resource
  • minus $OCF_RESKEY_CRM_meta_notify_stop_resource

• Inactive resources:

  • $OCF_RESKEY_CRM_meta_notify_inactive_resource
  • plus $OCF_RESKEY_CRM_meta_notify_stop_resource

• Resources to be started: $OCF_RESKEY_CRM_meta_notify_start_resource
• Resources to be promoted: $OCF_RESKEY_CRM_meta_notify_promote_resource
• Resources to be demoted: $OCF_RESKEY_CRM_meta_notify_demote_resource
• Resources to be stopped: $OCF_RESKEY_CRM_meta_notify_stop_resource
• Resources that were demoted: $OCF_RESKEY_CRM_meta_notify_demote_resource
• Resources that were stopped: $OCF_RESKEY_CRM_meta_notify_stop_resource

Post-notification (start) / Pre-notification (promote)

• Active resources:

  • $OCF_RESKEY_CRM_meta_notify_active_resource
  • minus $OCF_RESKEY_CRM_meta_notify_stop_resource
  • plus $OCF_RESKEY_CRM_meta_notify_start_resource

• Promoted resources:

  • $OCF_RESKEY_CRM_meta_notify_promoted_resource
  • minus $OCF_RESKEY_CRM_meta_notify_demote_resource

• Unpromoted resources:

  • $OCF_RESKEY_CRM_meta_notify_unpromoted_resource
  • minus $OCF_RESKEY_CRM_meta_notify_stop_resource
  • plus $OCF_RESKEY_CRM_meta_notify_start_resource

• Inactive resources:

  • $OCF_RESKEY_CRM_meta_notify_inactive_resource
  • plus $OCF_RESKEY_CRM_meta_notify_stop_resource
  • minus $OCF_RESKEY_CRM_meta_notify_start_resource

• Resources to be started: $OCF_RESKEY_CRM_meta_notify_start_resource
• Resources to be promoted: $OCF_RESKEY_CRM_meta_notify_promote_resource
• Resources to be demoted: $OCF_RESKEY_CRM_meta_notify_demote_resource
• Resources to be stopped: $OCF_RESKEY_CRM_meta_notify_stop_resource
• Resources that were started: $OCF_RESKEY_CRM_meta_notify_start_resource
• Resources that were demoted: $OCF_RESKEY_CRM_meta_notify_demote_resource
• Resources that were stopped: $OCF_RESKEY_CRM_meta_notify_stop_resource

Post-notification (promote)

• Active resources:

  • $OCF_RESKEY_CRM_meta_notify_active_resource
  • minus $OCF_RESKEY_CRM_meta_notify_stop_resource
  • plus $OCF_RESKEY_CRM_meta_notify_start_resource

• Promoted resources:

  • $OCF_RESKEY_CRM_meta_notify_promoted_resource
  • minus $OCF_RESKEY_CRM_meta_notify_demote_resource
  • plus $OCF_RESKEY_CRM_meta_notify_promote_resource

• Unpromoted resources:

  • $OCF_RESKEY_CRM_meta_notify_unpromoted_resource
  • minus $OCF_RESKEY_CRM_meta_notify_stop_resource
  • plus $OCF_RESKEY_CRM_meta_notify_start_resource
  • minus $OCF_RESKEY_CRM_meta_notify_promote_resource

• Inactive resources:

  • $OCF_RESKEY_CRM_meta_notify_inactive_resource
  • plus $OCF_RESKEY_CRM_meta_notify_stop_resource
  • minus $OCF_RESKEY_CRM_meta_notify_start_resource

• Resources to be started: $OCF_RESKEY_CRM_meta_notify_start_resource
• Resources to be promoted: $OCF_RESKEY_CRM_meta_notify_promote_resource
• Resources to be demoted: $OCF_RESKEY_CRM_meta_notify_demote_resource
• Resources to be stopped: $OCF_RESKEY_CRM_meta_notify_stop_resource
• Resources that were started: $OCF_RESKEY_CRM_meta_notify_start_resource
• Resources that were promoted: $OCF_RESKEY_CRM_meta_notify_promote_resource
• Resources that were demoted: $OCF_RESKEY_CRM_meta_notify_demote_resource
• Resources that were stopped: $OCF_RESKEY_CRM_meta_notify_stop_resource

12.3. LSB Resource Agents (Init Scripts)

12.3.1. LSB Compliance

The relevant part of the LSB specifications includes a description of all the return codes listed here.

Assuming some_service is configured correctly and currently inactive, the following sequence will help you determine if it is LSB-compatible:

1. Start (stopped):

   # /etc/init.d/some_service start ; echo "result: $?"
   

   • Did the service start?
   • Did the echo command print result: 0 (in addition to the init script’s usual output)?

2. Status (running):

   # /etc/init.d/some_service status ; echo "result: $?"
   

   • Did the script accept the command?
   • Did the script indicate the service was running?
   • Did the echo command print result: 0 (in addition to the init script’s usual output)?

3. Start (running):

   # /etc/init.d/some_service start ; echo "result: $?"
   

   • Is the service still running?

   • Did the echo command print result: 0 (in addition to the init

     script’s usual output)?

4. Stop (running):

   # /etc/init.d/some_service stop ; echo "result: $?"
   

   • Was the service stopped?
   • Did the echo command print result: 0 (in addition to the init script’s usual output)?

5. Status (stopped):

   # /etc/init.d/some_service status ; echo "result: $?"
   

   • Did the script accept the command?
   • Did the script indicate the service was not running?
   • Did the echo command print result: 3 (in addition to the init script’s usual output)?

6. Stop (stopped):

   # /etc/init.d/some_service stop ; echo "result: $?"
   

   • Is the service still stopped?
   • Did the echo command print result: 0 (in addition to the init script’s usual output)?

7. Status (failed):

   This step is not readily testable and relies on manual inspection of the script.

   The script can use one of the error codes (other than 3) listed in the LSB spec to indicate that it is active but failed. This tells the cluster that before moving the resource to another node, it needs to stop it on the existing one first.

If the answer to any of the above questions is no, then the script is not LSB-compliant. Your options are then to either fix the script or write an OCF agent based on the existing script.

13. Quick Comparison of pcs and crm shell

pcs and crm shell are two popular higher-level command-line interfaces to Pacemaker. Each has its own syntax; this chapter gives a quick comparion of how to accomplish the same tasks using either one. Some examples also show the equivalent command using low-level Pacemaker command-line tools.

These examples show the simplest syntax; see the respective man pages for all possible options.

13.1. Show Cluster Configuration and Status

Show Configuration (Raw XML)

crmsh     # crm configure show xml
pcs       # pcs cluster cib
pacemaker # cibadmin -Q

Show Configuration (Human-friendly)

crmsh # crm configure show
pcs   # pcs config

Show Cluster Status

crmsh     # crm status
pcs       # pcs status
pacemaker # crm_mon -1

13.2. Manage Nodes

Put node “pcmk-1” in standby mode

crmsh     # crm node standby pcmk-1
pcs-0.9   # pcs cluster standby pcmk-1
pcs-0.10  # pcs node standby pcmk-1
pacemaker # crm_standby -N pcmk-1 -v on

Remove node “pcmk-1” from standby mode

crmsh     # crm node online pcmk-1
pcs-0.9   # pcs cluster unstandby pcmk-1
pcs-0.10  # pcs node unstandby pcmk-1
pacemaker # crm_standby -N pcmk-1 -v off

13.3. Manage Cluster Properties

Set the “stonith-enabled” cluster property to “false”

crmsh     # crm configure property stonith-enabled=false
pcs       # pcs property set stonith-enabled=false
pacemaker # crm_attribute -n stonith-enabled -v false

13.4. Show Resource Agent Information

List Resource Agent (RA) Classes

crmsh    # crm ra classes
pcs      # pcs resource standards
pacmaker # crm_resource --list-standards

List Available Resource Agents (RAs) by Standard

crmsh     # crm ra list ocf
pcs       # pcs resource agents ocf
pacemaker # crm_resource --list-agents ocf

List Available Resource Agents (RAs) by OCF Provider

crmsh     # crm ra list ocf pacemaker
pcs       # pcs resource agents ocf:pacemaker
pacemaker # crm_resource --list-agents ocf:pacemaker

List Available Resource Agent Parameters

crmsh     # crm ra info IPaddr2
pcs       # pcs resource describe IPaddr2
pacemaker # crm_resource --show-metadata ocf:heartbeat:IPaddr2

You can also use the full class:provider:type format with crmsh and pcs if multiple RAs with the same name are available.

Show Available Fence Agent Parameters

crmsh # crm ra info stonith:fence_ipmilan
pcs   # pcs stonith describe fence_ipmilan

13.5. Manage Resources

Create a Resource

crmsh # crm configure primitive ClusterIP IPaddr2 params ip=192.168.122.120 cidr_netmask=24
pcs   # pcs resource create ClusterIP IPaddr2 ip=192.168.122.120 cidr_netmask=24

Both crmsh and pcs determine the standard and provider (ocf:heartbeat) automatically since IPaddr2 is unique, and automatically create operations (including monitor) based on the agent’s meta-data.

Show Configuration of All Resources

crmsh    # crm configure show
pcs-0.9  # pcs resource show --full
pcs-0.10 # pcs resource config

Show Configuration of One Resource

crmsh    # crm configure show ClusterIP
pcs-0.9  # pcs resource show ClusterIP
pcs-0.10 # pcs resource config ClusterIP

Show Configuration of Fencing Resources

crmsh    # crm resource status
pcs-0.9  # pcs stonith show --full
pcs-0.10 # pcs stonith config

Start a Resource

crmsh     # crm resource start ClusterIP
pcs       # pcs resource enable ClusterIP
pacemaker # crm_resource -r ClusterIP --set-parameter target-role --meta -v Started

Stop a Resource

crmsh     # crm resource stop ClusterIP
pcs       # pcs resource disable ClusterIP
pacemaker # crm_resource -r ClusterIP --set-parameter target-role --meta -v Stopped

Remove a Resource

crmsh # crm configure delete ClusterIP
pcs   # pcs resource delete ClusterIP

Modify a Resource’s Instance Parameters

crmsh     # crm resource param ClusterIP set clusterip_hash=sourceip
pcs       # pcs resource update ClusterIP clusterip_hash=sourceip
pacemaker # crm_resource -r ClusterIP --set-parameter clusterip_hash -v sourceip

crmsh also has an edit command which edits the simplified CIB syntax (same commands as the command line) via a configurable text editor.

Modify a Resource’s Instance Parameters Interactively

crmsh # crm configure edit ClusterIP

Using the interactive shell mode of crmsh, multiple changes can be edited and verified before committing to the live configuration:

Make Multiple Configuration Changes Interactively

crmsh # crm configure
crmsh # edit
crmsh # verify
crmsh # commit

Delete a Resource’s Instance Parameters

crmsh     # crm resource param ClusterIP delete nic
pcs       # pcs resource update ClusterIP nic=
pacemaker # crm_resource -r ClusterIP --delete-parameter nic

List Current Resource Defaults

crmsh     # crm configure show type:rsc_defaults
pcs       # pcs resource defaults
pacemaker # cibadmin -Q --scope rsc_defaults

Set Resource Defaults

crmsh # crm configure rsc_defaults resource-stickiness=100
pcs   # pcs resource defaults resource-stickiness=100

List Current Operation Defaults

crmsh     # crm configure show type:op_defaults
pcs       # pcs resource op defaults
pacemaker # cibadmin -Q --scope op_defaults

Set Operation Defaults

crmsh # crm configure op_defaults timeout=240s
pcs   # pcs resource op defaults timeout=240s

Enable Resource Agent Tracing for a Resource

crmsh # crm resource trace Website

Clear Fail Counts for a Resource

crmsh     # crm resource cleanup Website
pcs       # pcs resource cleanup Website
pacemaker # crm_resource --cleanup -r Website

Create a Clone Resource

crmsh # crm configure clone WebIP ClusterIP meta globally-unique=true clone-max=2 clone-node-max=2
pcs   # pcs resource clone ClusterIP globally-unique=true clone-max=2 clone-node-max=2

Create a Promotable Clone Resource

crmsh    # crm configure ms WebDataClone WebData \
           meta master-max=1 master-node-max=1 \
           clone-max=2 clone-node-max=1 notify=true
crmsh    # crm configure clone WebDataClone WebData \
           meta promotable=true \
           promoted-max=1 promoted-node-max=1 \
           clone-max=2 clone-node-max=1 notify=true
pcs-0.9  # pcs resource master WebDataClone WebData \
           master-max=1 master-node-max=1 \
           clone-max=2 clone-node-max=1 notify=true
pcs-0.10 # pcs resource promotable WebData WebDataClone \
           promoted-max=1 promoted-node-max=1 \
           clone-max=2 clone-node-max=1 notify=true

crmsh supports both ways (‘configure ms’ is deprecated) to configure promotable clone since crmsh 4.4.0. pcs will generate the clone name automatically if it is omitted from the command line.

13.6. Manage Constraints

Create a Colocation Constraint

crmsh # crm configure colocation website-with-ip INFINITY: WebSite ClusterIP
pcs   # pcs constraint colocation add ClusterIP with WebSite INFINITY

Create a Colocation Constraint Based on Role

crmsh # crm configure colocation another-ip-with-website inf: AnotherIP WebSite:Master
pcs   # pcs constraint colocation add Started AnotherIP with Promoted WebSite INFINITY

Create an Ordering Constraint

crmsh # crm configure order apache-after-ip mandatory: ClusterIP WebSite
pcs   # pcs constraint order ClusterIP then WebSite

Create an Ordering Constraint Based on Role

crmsh # crm configure order ip-after-website Mandatory: WebSite:Master AnotherIP
pcs   # pcs constraint order promote WebSite then start AnotherIP

Create a Location Constraint

crmsh # crm configure location prefer-pcmk-1 WebSite 50: pcmk-1
pcs   # pcs constraint location WebSite prefers pcmk-1=50

Create a Location Constraint Based on Role

crmsh # crm configure location prefer-pcmk-1 WebSite rule role=Master 50: \#uname eq pcmk-1
pcs   # pcs constraint location WebSite rule role=Promoted 50 \#uname eq pcmk-1

Move a Resource to a Specific Node (by Creating a Location Constraint)

crmsh     # crm resource move WebSite pcmk-1
pcs       # pcs resource move WebSite pcmk-1
pacemaker # crm_resource -r WebSite --move -N pcmk-1

Move a Resource Away from Its Current Node (by Creating a Location Constraint)

crmsh     # crm resource ban Website pcmk-2
pcs       # pcs resource ban Website pcmk-2
pacemaker # crm_resource -r WebSite --move

Remove any Constraints Created by Moving a Resource

crmsh     # crm resource unmove WebSite
pcs       # pcs resource clear WebSite
pacemaker # crm_resource -r WebSite --clear

13.7. Advanced Configuration

13.7.1. Manipulate Configuration Elements by Type

List Constraints with IDs

pcs   # pcs constraint list --full

Remove Constraint by ID

pcs   # pcs constraint remove cli-ban-Website-on-pcmk-1
crmsh # crm configure remove cli-ban-Website-on-pcmk-1

crmsh’s show and edit commands can be used to manage resources and constraints by type:

Show Configuration Elements

crmsh # crm configure show type:primitive
crmsh # crm configure edit type:colocation

13.7.2. Batch Changes

Make Multiple Changes and Apply Together

crmsh # crm
crmsh # cib new drbd_cfg
crmsh # configure primitive WebData ocf:linbit:drbd params drbd_resource=wwwdata \
        op monitor interval=60s
crmsh # configure ms WebDataClone WebData meta master-max=1 master-node-max=1 \
        clone-max=2 clone-node-max=1 notify=true
crmsh # cib commit drbd_cfg
crmsh # quit

pcs      # pcs cluster cib drbd_cfg
pcs      # pcs -f drbd_cfg resource create WebData ocf:linbit:drbd drbd_resource=wwwdata \
           op monitor interval=60s
pcs-0.9  # pcs -f drbd_cfg resource master WebDataClone WebData \
           master-max=1 master-node-max=1 clone-max=2 clone-node-max=1 notify=true
pcs-0.10 # pcs -f drbd_cfg resource promotable WebData WebDataClone \
           promoted-max=1 promoted-node-max=1 clone-max=2 clone-node-max=1 notify=true
pcs      # pcs cluster cib-push drbd_cfg

13.7.3. Template Creation

Create Resource Template Based on Existing Primitives of Same Type

crmsh # crm configure assist template ClusterIP AdminIP

13.7.4. Log Analysis

Show Information About Recent Cluster Events

crmsh # crm history
crmsh # peinputs
crmsh # transition pe-input-10
crmsh # transition log pe-input-10

13.7.5. Configuration Scripts

Script Multiple-step Cluster Configurations

crmsh # crm script show apache
crmsh # crm script run apache \
        id=WebSite \
        install=true \
        virtual-ip:ip=192.168.0.15 \
        database:id=WebData \
        database:install=true

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