How to modify the resource parameter in Pacemaker cluster?

Environment

• Red Hat Enterprise Linux Server 6, 7, 8, and 9 (with the High Availability Add On)
• pacemaker

Issue

• How do you modify a resource parameter in pacemaker cluster?

Resolution

Following command can be used to modify the resource parameter in Pacemaker cluster.

# pcs resource update <resource id> [resource options] [op [<operation action <operation options>]...] [meta <meta operations>...] [--wait[=n]]

For example, following command can be used to modify the IP address of a VIP resource.

# pcs resource update VIP_B ip=192.168.122.111

When a resource is modified the resource may restart if the reload operation is not available for the resource or the updated parameter does not have the unique=0 attribute set as discussed in below document.

• How to tell whether pacemaker resource will restart or not after updating parameter with pcs resource update <resourceid> <parameter>?

This could cause any constraints or dependencies (if part of a group) to be stopped first as well.

If the resource is part of a Master/Slave resource then the resource will be demoted on all nodes and then a Master(s) will be prompted. In both instances this will cause a momentary outage.

In order to ensure a resource does not restart following an update, you can put the cluster in maintenance mode first. When the resource parameter is modified, it won't restart, until you leave maintenance mode.

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