Our first resource will be a unique IP address that the cluster can bring up on either node. Regardless of where any cluster service(s) are running, end users need a consistent address to contact them on. Here, I will choose 192.168.122.120 as the floating address, give it the imaginative name ClusterIP and tell the cluster to check whether it is running every 30 seconds.
The chosen address must not already be in use on the network. Do not reuse an IP address one of the nodes already has configured.
[root@pcmk-1 ~]# pcs resource create ClusterIP ocf:heartbeat:IPaddr2 \
ip=192.168.122.120 cidr_netmask=24 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:
The first field (ocf in this case) is the standard to which the resource script conforms and where to find it.
The second field (heartbeat in this case) is standard-specific; for OCF resources, it tells the cluster which OCF namespace the resource script is in.
The third field (IPaddr2 in this case) is the name of the resource script.
To obtain a list of the available resource standards (the ocf part of ocf:heartbeat:IPaddr2), run:
[root@pcmk-1 ~]# pcs resource standards
lsb
ocf
service
systemd
To obtain a list of the available OCF resource providers (the heartbeat part of ocf:heartbeat:IPaddr2), run:
[root@pcmk-1 ~]# pcs resource providers
heartbeat
openstack
pacemaker
Finally, if you want to see all the resource agents available for a specific OCF provider (the IPaddr2 part of ocf:heartbeat:IPaddr2), run:
[root@pcmk-1 ~]# pcs resource agents ocf:heartbeat
apache
aws-vpc-move-ip
awseip
awsvip
azure-lb
clvm
.
. (skipping lots of resources to save space)
.
symlink
tomcat
VirtualDomain
Xinetd
Now, verify that the IP resource has been added, and display the cluster’s status to see that it is now active:
[root@pcmk-1 ~]# pcs status
Cluster name: mycluster
Stack: corosync
Current DC: pcmk-2 (version 1.1.18-11.el7_5.3-2b07d5c5a9) - partition with quorum
Last updated: Mon Sep 10 16:55:26 2018
Last change: Mon Sep 10 16:53:42 2018 by root via cibadmin on pcmk-1
2 nodes configured
1 resource configured
Online: [ pcmk-1 pcmk-2 ]
Full list of resources:
ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1
Daemon Status:
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/enabled
