Configuration Recap
-------------------
Final Cluster Configuration
###########################
.. code-block:: console
[root@pcmk-1 ~]# pcs resource
* ClusterIP (ocf:heartbeat:IPaddr2): Started pcmk-1
* WebSite (ocf:heartbeat:apache): Started pcmk-1
* Clone Set: WebData-clone [WebData] (promotable):
* Promoted: [ pcmk-1 pcmk-2 ]
* Clone Set: dlm-clone [dlm]:
* Started: [ pcmk-1 pcmk-2 ]
* Clone Set: WebFS-clone [WebFS]:
* Started: [ pcmk-1 pcmk-2 ]
.. code-block:: console
[root@pcmk-1 ~]# pcs resource op defaults
Meta Attrs: op_defaults-meta_attributes
timeout=240s
.. code-block:: console
[root@pcmk-1 ~]# pcs stonith
* fence_dev (stonith:some_fence_agent): Started pcmk-1
.. code-block:: console
[root@pcmk-1 ~]# pcs constraint
Location Constraints:
Resource: WebSite
Enabled on:
Node: pcmk-2 (score:50)
Ordering Constraints:
start ClusterIP then start WebSite (kind:Mandatory)
promote WebData-clone then start WebFS-clone (kind:Mandatory)
start WebFS-clone then start WebSite (kind:Mandatory)
start dlm-clone then start WebFS-clone (kind:Mandatory)
Colocation Constraints:
WebSite with ClusterIP (score:INFINITY)
WebFS-clone with WebData-clone (score:INFINITY) (rsc-role:Started) (with-rsc-role:Promoted)
WebSite with WebFS-clone (score:INFINITY)
WebFS-clone with dlm-clone (score:INFINITY)
Ticket Constraints:
.. code-block:: console
[root@pcmk-1 ~]# pcs status
Cluster name: mycluster
Cluster Summary:
* Stack: corosync
* Current DC: pcmk-1 (version 2.1.2-4.el9-ada5c3b36e2) - partition with quorum
* Last updated: Wed Jul 27 08:57:57 2022
* Last change: Wed Jul 27 08:55:00 2022 by root via cibadmin on pcmk-1
* 2 nodes configured
* 9 resource instances configured
Node List:
* Online: [ pcmk-1 pcmk-2 ]
Full List of Resources:
* fence_dev (stonith:some_fence_agent): Started pcmk-1
* ClusterIP (ocf:heartbeat:IPaddr2): Started pcmk-1
* WebSite (ocf:heartbeat:apache): Started pcmk-1
* Clone Set: WebData-clone [WebData] (promotable):
* Promoted: [ pcmk-1 pcmk-2 ]
* Clone Set: dlm-clone [dlm]:
* Started: [ pcmk-1 pcmk-2 ]
* Clone Set: WebFS-clone [WebFS]:
* Started: [ pcmk-1 pcmk-2 ]
Daemon Status:
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/enabled
.. code-block:: console
[root@pcmk-1 ~]# pcs config
Cluster Name: mycluster
Corosync Nodes:
pcmk-1 pcmk-2
Pacemaker Nodes:
pcmk-1 pcmk-2
Resources:
Resource: ClusterIP (class=ocf provider=heartbeat type=IPaddr2)
Attributes: cidr_netmask=24 ip=192.168.122.120
Operations: monitor interval=30s (ClusterIP-monitor-interval-30s)
start interval=0s timeout=20s (ClusterIP-start-interval-0s)
stop interval=0s timeout=20s (ClusterIP-stop-interval-0s)
Resource: WebSite (class=ocf provider=heartbeat type=apache)
Attributes: configfile=/etc/httpd/conf/httpd.conf statusurl=http://localhost/server-status
Operations: monitor interval=1min (WebSite-monitor-interval-1min)
start interval=0s timeout=40s (WebSite-start-interval-0s)
stop interval=0s timeout=60s (WebSite-stop-interval-0s)
Clone: WebData-clone
Meta Attrs: clone-max=2 clone-node-max=1 notify=true promotable=true promoted-max=2 promoted-node-max=1
Resource: WebData (class=ocf provider=linbit type=drbd)
Attributes: drbd_resource=wwwdata
Operations: demote interval=0s timeout=90 (WebData-demote-interval-0s)
monitor interval=29s role=Promoted (WebData-monitor-interval-29s)
monitor interval=31s role=Unpromoted (WebData-monitor-interval-31s)
notify interval=0s timeout=90 (WebData-notify-interval-0s)
promote interval=0s timeout=90 (WebData-promote-interval-0s)
reload interval=0s timeout=30 (WebData-reload-interval-0s)
start interval=0s timeout=240 (WebData-start-interval-0s)
stop interval=0s timeout=100 (WebData-stop-interval-0s)
Clone: dlm-clone
Meta Attrs: interleave=true ordered=true
Resource: dlm (class=ocf provider=pacemaker type=controld)
Operations: monitor interval=60s (dlm-monitor-interval-60s)
start interval=0s timeout=90s (dlm-start-interval-0s)
stop interval=0s timeout=100s (dlm-stop-interval-0s)
Clone: WebFS-clone
Resource: WebFS (class=ocf provider=heartbeat type=Filesystem)
Attributes: device=/dev/drbd1 directory=/var/www/html fstype=gfs2
Operations: monitor interval=20s timeout=40s (WebFS-monitor-interval-20s)
start interval=0s timeout=60s (WebFS-start-interval-0s)
stop interval=0s timeout=60s (WebFS-stop-interval-0s)
Stonith Devices:
Resource: fence_dev (class=stonith type=some_fence_agent)
Attributes: pcmk_delay_base=pcmk-1:5s;pcmk-2:0s pcmk_host_map=pcmk-1:almalinux9-1;pcmk-2:almalinux9-2
Operations: monitor interval=60s (fence_dev-monitor-interval-60s)
Fencing Levels:
Location Constraints:
Resource: WebSite
Enabled on:
Node: pcmk-2 (score:50) (id:location-WebSite-pcmk-2-50)
Ordering Constraints:
start ClusterIP then start WebSite (kind:Mandatory) (id:order-ClusterIP-WebSite-mandatory)
promote WebData-clone then start WebFS-clone (kind:Mandatory) (id:order-WebData-clone-WebFS-mandatory)
start WebFS-clone then start WebSite (kind:Mandatory) (id:order-WebFS-WebSite-mandatory)
start dlm-clone then start WebFS-clone (kind:Mandatory) (id:order-dlm-clone-WebFS-mandatory)
Colocation Constraints:
WebSite with ClusterIP (score:INFINITY) (id:colocation-WebSite-ClusterIP-INFINITY)
WebFS-clone with WebData-clone (score:INFINITY) (rsc-role:Started) (with-rsc-role:Promoted) (id:colocation-WebFS-WebData-clone-INFINITY)
WebSite with WebFS-clone (score:INFINITY) (id:colocation-WebSite-WebFS-INFINITY)
WebFS-clone with dlm-clone (score:INFINITY) (id:colocation-WebFS-dlm-clone-INFINITY)
Ticket Constraints:
Alerts:
No alerts defined
Resources Defaults:
Meta Attrs: build-resource-defaults
resource-stickiness=100
Operations Defaults:
Meta Attrs: op_defaults-meta_attributes
timeout=240s
Cluster Properties:
cluster-infrastructure: corosync
cluster-name: mycluster
dc-version: 2.1.2-4.el9-ada5c3b36e2
have-watchdog: false
last-lrm-refresh: 1658896047
no-quorum-policy: freeze
stonith-enabled: true
Tags:
No tags defined
Quorum:
Options:
Node List
#########
.. code-block:: console
[root@pcmk-1 ~]# pcs status nodes
Pacemaker Nodes:
Online: pcmk-1 pcmk-2
Standby:
Standby with resource(s) running:
Maintenance:
Offline:
Pacemaker Remote Nodes:
Online:
Standby:
Standby with resource(s) running:
Maintenance:
Offline:
Cluster Options
###############
.. code-block:: console
[root@pcmk-1 ~]# pcs property
Cluster Properties:
cluster-infrastructure: corosync
cluster-name: mycluster
dc-version: 2.1.2-4.el9-ada5c3b36e2
have-watchdog: false
no-quorum-policy: freeze
stonith-enabled: true
The output shows cluster-wide configuration options, as well as some baseline-
level state information. The output includes:
* ``cluster-infrastructure`` - the cluster communications layer in use
* ``cluster-name`` - the cluster name chosen by the administrator when the
cluster was created
* ``dc-version`` - the version (including upstream source-code hash) of
``pacemaker`` used on the Designated Controller, which is the node elected to
determine what actions are needed when events occur
* ``have-watchdog`` - whether watchdog integration is enabled; set
automatically when SBD is enabled
* ``stonith-enabled`` - whether nodes may be fenced as part of recovery
.. NOTE::
This command is equivalent to ``pcs property config``.
Resources
#########
Default Options
_______________
.. code-block:: console
[root@pcmk-1 ~]# pcs resource defaults
Meta Attrs: build-resource-defaults
resource-stickiness=100
This shows cluster option defaults that apply to every resource that does not
explicitly set the option itself. Above:
* ``resource-stickiness`` - Specify how strongly a resource prefers to remain
on its current node. Alternatively, you can view this as the level of
aversion to moving healthy resources to other machines.
Fencing
_______
.. code-block:: console
[root@pcmk-1 ~]# pcs stonith status
* fence_dev (stonith:some_fence_agent): Started pcmk-1
[root@pcmk-1 ~]# pcs stonith config
Resource: fence_dev (class=stonith type=some_fence_agent)
Attributes: pcmk_delay_base=pcmk-1:5s;pcmk-2:0s pcmk_host_map=pcmk-1:almalinux9-1;pcmk-2:almalinux9-2
Operations: monitor interval=60s (fence_dev-monitor-interval-60s)
Service Address
_______________
Users of the services provided by the cluster require an unchanging
address with which to access it.
.. code-block:: console
[root@pcmk-1 ~]# pcs resource config ClusterIP
Resource: ClusterIP (class=ocf provider=heartbeat type=IPaddr2)
Attributes: cidr_netmask=24 ip=192.168.122.120
Operations: monitor interval=30s (ClusterIP-monitor-interval-30s)
start interval=0s timeout=20s (ClusterIP-start-interval-0s)
stop interval=0s timeout=20s (ClusterIP-stop-interval-0s)
DRBD - Shared Storage
_____________________
Here, we define the DRBD service and specify which DRBD resource (from
``/etc/drbd.d/\*.res``) it should manage. We make it a promotable clone
resource and, in order to have an active/active setup, allow both instances to
be promoted at the same time. We also set the notify option so that the cluster
will tell the ``drbd`` agent when its peer changes state.
.. code-block:: console
[root@pcmk-1 ~]# pcs resource config WebData-clone
Clone: WebData-clone
Meta Attrs: clone-max=2 clone-node-max=1 notify=true promotable=true promoted-max=2 promoted-node-max=1
Resource: WebData (class=ocf provider=linbit type=drbd)
Attributes: drbd_resource=wwwdata
Operations: demote interval=0s timeout=90 (WebData-demote-interval-0s)
monitor interval=29s role=Promoted (WebData-monitor-interval-29s)
monitor interval=31s role=Unpromoted (WebData-monitor-interval-31s)
notify interval=0s timeout=90 (WebData-notify-interval-0s)
promote interval=0s timeout=90 (WebData-promote-interval-0s)
reload interval=0s timeout=30 (WebData-reload-interval-0s)
start interval=0s timeout=240 (WebData-start-interval-0s)
stop interval=0s timeout=100 (WebData-stop-interval-0s)
[root@pcmk-1 ~]# pcs constraint ref WebData-clone
Resource: WebData-clone
colocation-WebFS-WebData-clone-INFINITY
order-WebData-clone-WebFS-mandatory
Cluster Filesystem
__________________
The cluster filesystem ensures that files are read and written correctly.
We need to specify the block device (provided by DRBD), where we want it
mounted and that we are using GFS2. Again, it is a clone because it is
intended to be active on both nodes. The additional constraints ensure
that it can only be started on nodes with active DLM and DRBD instances.
.. code-block:: console
[root@pcmk-1 ~]# pcs resource config WebFS-clone
Clone: WebFS-clone
Resource: WebFS (class=ocf provider=heartbeat type=Filesystem)
Attributes: device=/dev/drbd1 directory=/var/www/html fstype=gfs2
Operations: monitor interval=20s timeout=40s (WebFS-monitor-interval-20s)
start interval=0s timeout=60s (WebFS-start-interval-0s)
stop interval=0s timeout=60s (WebFS-stop-interval-0s)
[root@pcmk-1 ~]# pcs constraint ref WebFS-clone
Resource: WebFS-clone
colocation-WebFS-WebData-clone-INFINITY
colocation-WebSite-WebFS-INFINITY
colocation-WebFS-dlm-clone-INFINITY
order-WebData-clone-WebFS-mandatory
order-WebFS-WebSite-mandatory
order-dlm-clone-WebFS-mandatory
Apache
______
Lastly, we have the actual service, Apache. We need only tell the cluster
where to find its main configuration file and restrict it to running on
a node that has the required filesystem mounted and the IP address active.
.. code-block:: console
[root@pcmk-1 ~]# pcs resource config WebSite
Resource: WebSite (class=ocf provider=heartbeat type=apache)
Attributes: configfile=/etc/httpd/conf/httpd.conf statusurl=http://localhost/server-status
Operations: monitor interval=1min (WebSite-monitor-interval-1min)
start interval=0s timeout=40s (WebSite-start-interval-0s)
stop interval=0s timeout=60s (WebSite-stop-interval-0s)
[root@pcmk-1 ~]# pcs constraint ref WebSite
Resource: WebSite
colocation-WebSite-ClusterIP-INFINITY
colocation-WebSite-WebFS-INFINITY
location-WebSite-pcmk-2-50
order-ClusterIP-WebSite-mandatory
order-WebFS-WebSite-mandatory