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Update Clusters From Scratch for pacemaker-3.0 / Alma Linux 10 #4063

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07613d8
Doc: books: Update documentation OS version.
clumens Feb 24, 2026
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Doc: Clusters from Scratch: Remove unused WelcomeToCentos.png image.
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d60dd1b
Doc: Clusters from Scratch: Update Installation chapter.
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Doc: Clusters from Scratch: Update Cluster Setup chapter.
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Doc: Clusters from Scratch: Update Start and Verify Cluster chapter.
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Doc: Clusters from Scratch: Update Active/Passive chapter.
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Doc: Clusters from Scratch: Update Apache chapter.
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Doc: Clusters from Scratch: Update DRBD chapter.
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Doc: Clusters from Scratch: Update GFS2 chapter.
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Doc: Clusters from Scratch: Update index.rst.
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193 changes: 130 additions & 63 deletions doc/sphinx/Clusters_from_Scratch/active-active.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,13 @@
Convert Storage to Active/Active
--------------------------------

.. NOTE::

GFS2 is not available in a package repo for |CFS_DISTRO| |CFS_DISTRO_VER|.
It can still be built from source, but doing so is scope of this document.
The following instructions are still useful for older distributions or
for installation from source. They have been updated where possible.

The primary requirement for an active/active cluster is that the data
required for your services is available, simultaneously, on both
machines. Pacemaker makes no requirement on how this is achieved; you
Expand Down Expand Up @@ -68,38 +75,80 @@ Activate our new configuration, and see how the cluster responds:
* Started: [ pcmk-1 pcmk-2 ]
[root@pcmk-1 ~]# pcs resource config
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)
Attributes: ClusterIP-instance_attributes
cidr_netmask=24
ip=192.168.122.120
nic=enp1s0
Operations:
monitor: ClusterIP-monitor-interval-30s
interval=30s
start: ClusterIP-start-interval-0s
interval=0s timeout=20s
stop: ClusterIP-stop-interval-0s
interval=0s timeout=20s
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)
Attributes: WebSite-instance_attributes
configfile=/etc/httpd/conf/httpd.conf
statusurl=http://localhost/server-status
Operations:
monitor: WebSite-monitor-interval-1min
interval=1min
start: WebSite-start-interval-0s
interval=0s timeout=40s
stop: WebSite-stop-interval-0s
interval=0s timeout=60s
Resource: WebFS (class=ocf provider=heartbeat type=Filesystem)
Attributes: WebFS-instance_attributes
device=/dev/drbd1
directory=/var/www/html
fstype=xfs
Operations:
monitor: WebFS-monitor-interval-20s
interval=20s timeout=40s
start: WebFS-start-interval-0s
interval=0s timeout=60s
stop: WebFS-stop-interval-0s
interval=0s timeout=60s
Clone: WebData-clone
Meta Attrs: clone-max=2 clone-node-max=1 notify=true promotable=true promoted-max=1 promoted-node-max=1
Meta Attributes: WebData-clone-meta_attributes
clone-max=2
clone-node-max=1
notify=true
promotable=true
promoted-max=1
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)
Resource: WebFS (class=ocf provider=heartbeat type=Filesystem)
Attributes: device=/dev/drbd1 directory=/var/www/html fstype=xfs
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)
Attributes: WebData-instance_attributes
drbd_resource=wwwdata
Operations:
demote: WebData-demote-interval-0s
interval=0s timeout=90
monitor: WebData-monitor-interval-29s
interval=29s role=Promoted
monitor: WebData-monitor-interval-31s
interval=31s role=Unpromoted
notify: WebData-notify-interval-0s
interval=0s timeout=90
promote: WebData-promote-interval-0s
interval=0s timeout=90
reload: WebData-reload-interval-0s
interval=0s timeout=30
start: WebData-start-interval-0s
interval=0s timeout=240
stop: WebData-stop-interval-0s
interval=0s timeout=100
Clone: dlm-clone
Meta Attrs: interleave=true ordered=true
Meta Attributes: dlm-clone-meta_attributes
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)
Operations:
monitor: dlm-monitor-interval-60s
interval=60s
start: dlm-start-interval-0s
interval=0s timeout=90
stop: dlm-stop-interval-0s
interval=0s timeout=100

Create and Populate GFS2 Filesystem
###################################
Expand Down Expand Up @@ -202,11 +251,19 @@ With the ``WebFS`` resource stopped, let's update the configuration.

[root@pcmk-1 ~]# pcs resource config WebFS
Resource: WebFS (class=ocf provider=heartbeat type=Filesystem)
Attributes: device=/dev/drbd1 directory=/var/www/html fstype=xfs
Meta Attrs: target-role=Stopped
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)
Attributes: WebFS-instance_attributes
device=/dev/drbd1
directory=/var/www/html
fstype=xfs
Meta Attributes: WebFS-meta_attributes
target-role=Stopped
Operations:
monitor: WebFS-monitor-interval-20s
interval=20s timeout=40s
start: WebFS-start-interval-0s
interval=0s timeout=60s
stop: WebFS-stop-interval-0s
interval=0s timeout=60s

The fstype option needs to be updated to ``gfs2`` instead of ``xfs``.

Expand All @@ -215,11 +272,19 @@ The fstype option needs to be updated to ``gfs2`` instead of ``xfs``.
[root@pcmk-1 ~]# pcs resource update WebFS fstype=gfs2
[root@pcmk-1 ~]# pcs resource config WebFS
Resource: WebFS (class=ocf provider=heartbeat type=Filesystem)
Attributes: device=/dev/drbd1 directory=/var/www/html fstype=gfs2
Meta Attrs: target-role=Stopped
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)
Attributes: WebFS-instance_attributes
device=/dev/drbd1
directory=/var/www/html
fstype=gfs2
Meta Attributes: WebFS-meta_attributes
target-role=Stopped
Operations:
monitor: WebFS-monitor-interval-20s
interval=20s timeout=40s
start: WebFS-start-interval-0s
interval=0s timeout=60s
stop: WebFS-stop-interval-0s
interval=0s timeout=60s

GFS2 requires that DLM be running, so we also need to set up new colocation
and ordering constraints for it:
Expand All @@ -231,20 +296,21 @@ and ordering constraints for it:
Adding dlm-clone WebFS (kind: Mandatory) (Options: first-action=start then-action=start)
[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 (kind:Mandatory)
start WebFS then start WebSite (kind:Mandatory)
start dlm-clone then start WebFS (kind:Mandatory)
resource 'WebSite' prefers node 'pcmk-2' with score 50
Colocation Constraints:
WebSite with ClusterIP (score:INFINITY)
WebFS with WebData-clone (score:INFINITY) (rsc-role:Started) (with-rsc-role:Promoted)
WebSite with WebFS (score:INFINITY)
WebFS with dlm-clone (score:INFINITY)
Ticket Constraints:
resource 'WebSite' with resource 'ClusterIP'
score=INFINITY
resource 'WebFS' with Promoted resource 'WebData-clone'
score=INFINITY
resource 'WebSite' with resource 'WebFS'
score=INFINITY
resource 'WebFS' with resource 'dlm-clone'
score=INFINITY
Order Constraints:
start resource 'ClusterIP' then start resource 'WebSite'
promote resource 'WebData-clone' then start resource 'WebFS'
start resource 'WebFS' then start resource 'WebSite'
start resource 'dlm-clone' then start resource 'WebFS'

We also need to update the ``no-quorum-policy`` property to ``freeze``. By
default, the value of ``no-quorum-policy`` is set to ``stop`` indicating that
Expand Down Expand Up @@ -283,20 +349,21 @@ Notice how ``pcs`` automatically updates the relevant constraints again.
[root@pcmk-1 ~]# pcs -f active_cfg resource clone WebFS
[root@pcmk-1 ~]# pcs -f active_cfg 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)
resource 'WebSite' prefers node 'pcmk-2' with score 50
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:
resource 'WebSite' with resource 'ClusterIP'
score=INFINITY
resource 'WebFS-clone' with Promoted resource 'WebData-clone'
score=INFINITY
resource 'WebSite' with resource 'WebFS-clone'
score=INFINITY
resource 'WebFS-clone' with resource 'dlm-clone'
score=INFINITY
Order Constraints:
start resource 'ClusterIP' then start resource 'WebSite'
promote resource 'WebData-clone' then start resource 'WebFS-clone'
start resource 'WebFS-clone' then start resource 'WebSite'
start resource 'dlm-clone' then start resource 'WebFS-clone'

Tell the cluster that it is now allowed to promote both instances to be DRBD
Primary.
Expand Down
36 changes: 18 additions & 18 deletions doc/sphinx/Clusters_from_Scratch/active-passive.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -11,8 +11,9 @@ Our first resource will be a floating IP address that the cluster can bring up
on either node. Regardless of where any cluster service(s) are running, end
users need to be able to communicate with them at a consistent address. Here,
we will use ``192.168.122.120`` as the floating IP address, give it the
imaginative name ``ClusterIP``, and tell the cluster to check whether it is
still running every 30 seconds.
imaginative name ``ClusterIP``, assign the IP address to the physical device
``enp1s0``, and tell the cluster to check whether it is still running every 30
seconds.

.. WARNING::

Expand All @@ -22,8 +23,8 @@ still running every 30 seconds.

.. code-block:: console

[root@pcmk-1 ~]# pcs resource create ClusterIP ocf:heartbeat:IPaddr2 \
ip=192.168.122.120 cidr_netmask=24 op monitor interval=30s
[root@pcmk-1 ~]# pcs resource create ClusterIP ocf:heartbeat:IPaddr2 \
ip=192.168.122.120 cidr_netmask=24 nic=enp1s0 op monitor interval=30s

Another important piece of information here is ``ocf:heartbeat:IPaddr2``.
This tells Pacemaker three things about the resource you want to add:
Expand Down Expand Up @@ -87,10 +88,10 @@ now, but it's okay if it doesn't look like the one below.
[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 00:37:28 2022
* Last change: Wed Jul 27 00:37:14 2022 by root via cibadmin on pcmk-1
* Stack: corosync (Pacemaker is running)
* Current DC: pcmk-1 (version 3.0.1-3.el10-6a90427) - partition with quorum
* Last updated: Tue Feb 24 15:19:53 2026 on pcmk-1
* Last change: Tue Feb 24 15:19:16 2026 by root via root on pcmk-1
* 2 nodes configured
* 2 resource instances configured

Expand All @@ -115,7 +116,7 @@ address has been added.
1: lo inet 127.0.0.1/8 scope host lo\ valid_lft forever preferred_lft forever
1: lo inet6 ::1/128 scope host \ valid_lft forever preferred_lft forever
2: enp1s0 inet 192.168.122.102/24 brd 192.168.122.255 scope global noprefixroute enp1s0\ valid_lft forever preferred_lft forever
2: enp1s0 inet 192.168.122.120/24 brd 192.168.122.255 scope global secondary enp1s0\ valid_lft forever preferred_lft forever
2: enp1s0 inet 192.168.122.120/24 scope global enp1s0\ valid_lft forever preferred_lft forever
2: enp1s0 inet6 fe80::5054:ff:fe95:209/64 scope link noprefixroute \ valid_lft forever preferred_lft forever

Perform a Failover
Expand Down Expand Up @@ -150,7 +151,6 @@ Verify that ``pacemaker`` and ``corosync`` are no longer running:

[root@pcmk-2 ~]# pcs status
Error: error running crm_mon, is pacemaker running?
Could not connect to pacemakerd: Connection refused
crm_mon: Connection to cluster failed: Connection refused

Go to the other node, and check the cluster status.
Expand All @@ -160,10 +160,10 @@ Go to the other node, and check the cluster status.
[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 00:43:51 2022
* Last change: Wed Jul 27 00:43:14 2022 by root via cibadmin on pcmk-1
* Stack: corosync (Pacemaker is running)
* Current DC: pcmk-1 (version 3.0.1-3.el10-6a90427) - partition with quorum
* Last updated: Tue Feb 24 15:23:32 2026 on pcmk-2
* Last change: Tue Feb 24 15:19:16 2026 by root via root on pcmk-1
* 2 nodes configured
* 2 resource instances configured

Expand Down Expand Up @@ -251,10 +251,10 @@ gets going on the node, but it eventually will look like the below.)
[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 00:45:17 2022
* Last change: Wed Jul 27 00:45:01 2022 by root via cibadmin on pcmk-1
* Stack: corosync (Pacemaker is running)
* Current DC: pcmk-1 (version 3.0.1-3.el10-6a90427) - partition with quorum
* Last updated: Tue Feb 24 15:27:35 2026 on pcmk-2
* Last change: Tue Feb 24 15:19:16 2026 by root via root on pcmk-1
* 2 nodes configured
* 2 resource instances configured

Expand Down
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