.. index::
single: configuration
single: CIB
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.
Configuration Using Higher-level Tools
######################################
Most users will benefit from using higher-level tools provided by projects
separate from Pacemaker. Some of the most commonly used include the crm shell,
hawk, and pcs. [#]_
See those projects' documentation for details on how to configure Pacemaker
using them.
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:
.. code-block:: none
# crm_attribute --name stonith-enabled --update 1
Or, to check whether **node1** is allowed to run resources, there is:
.. code-block:: none
# crm_standby --query --node node1
Or, to change the failure threshold of **my-test-rsc**, one can use:
.. code-block:: none
# 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 :ref:`cibadmin` for how to edit the CIB using XML.
See :ref:`crm_shadow` for a way to make a series of changes, then commit them
all at once to the live cluster.
.. index::
single: configuration; CIB properties
single: CIB; properties
single: CIB property
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:
.. code-block:: none
# cibadmin --modify --xml-text ''
A complete set of CIB properties will look something like this:
.. topic:: XML attributes set for a cib element
.. code-block:: xml
.. index::
single: configuration; cluster options
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:
.. code-block:: none
# crm_attribute --query --name cluster-delay
which is more simply written as
.. code-block:: none
# crm_attribute -G -n cluster-delay
If a value is found, you'll see a result like this:
.. code-block:: none
# 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:
.. code-block:: none
# 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:
.. code-block:: none
# crm_attribute --name cluster-delay --update 30s
To go back to the cluster's default value, you can delete the value, for example:
.. code-block:: none
# crm_attribute --name cluster-delay --delete
Deleted crm_config option: id=cib-bootstrap-options-cluster-delay name=cluster-delay
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.
.. topic:: Deleting an option that is listed twice
.. code-block:: none
# 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*.
.. index::
single: configuration; remote
.. _remote_connection:
Connecting from a Remote Machine
################################
Provided Pacemaker is installed on a machine, it is possible to connect to the
cluster even if the machine itself is not in the same cluster. To do this, one
simply sets up a number of environment variables and runs the same commands as
when working on a cluster node.
.. list-table:: **Environment Variables Used to Connect to Remote Instances of the CIB**
:class: longtable
:widths: 2 2 5
:header-rows: 1
* - Environment Variable
- Default
- Description
* - .. index::
single: CIB_user
single: environment variable; CIB_user
CIB_user
- |CRM_DAEMON_USER_RAW|
- The user to connect as. Needs to be part of the |CRM_DAEMON_GROUP| group
on the target host.
* - .. index::
single: CIB_passwd
single: environment variable; CIB_passwd
CIB_passwd
-
- The user's password. Read from the command line if unset.
* - .. index::
single: CIB_server
single: environment variable; CIB_server
CIB_server
- localhost
- The host to contact
* - .. index::
single: CIB_port
single: environment variable; CIB_port
CIB_port
-
- The port on which to contact the server; required
* - .. index::
single: CIB_encrypted
single: environment variable; CIB_encrypted
CIB_encrypted
- true
- Whether to encrypt network traffic
So, if **c001n01** is an active cluster node and is listening on port 1234
for connections, and **someuser** is a member of the |CRM_DAEMON_GROUP| group,
then the following would prompt for **someuser**'s password and return
the cluster's current configuration:
.. code-block:: none
# export CIB_port=1234; export CIB_server=c001n01; export CIB_user=someuser;
# cibadmin -Q
For security reasons, the cluster does not listen for remote connections by
default. If you wish to allow remote access, you need to set the
``remote-tls-port`` (encrypted) or ``remote-clear-port`` (unencrypted) CIB
properties (i.e., those kept in the ``cib`` tag, like ``num_updates`` and
``epoch``). Encrypted communication is keyless, which makes it subject to
man-in-the-middle attacks, and thus either option should be used only on
protected networks.
.. important::
The Pacemaker version on the administration host must be the same or greater
than the version(s) on the cluster nodes. Otherwise, it may not have the
schema files necessary to validate the CIB.
.. rubric:: Footnotes
.. [#] For a list, see "Configuration Tools" at
https://clusterlabs.org/components.html