19.7. Configuring a node health strategy

Procedure

1. Set the health-node-strategy cluster property to define how Pacemaker responds to changes in node health.

   # pcs property set node-health-strategy=migrate-on-red

2. Create a cloned cluster resource that uses a health node resource agent, setting the allow-unhealthy-nodes resource meta option to define whether the cluster will detect if the node’s health recovers and move resources back to the node. Configure this resource with a recurring monitor action, to continually check the health of all nodes.

   This example creates a HealthIOWait resource agent to monitor the CPU I/O wait, setting a red limit for moving resources off a node to 15%. This command sets the allow-unhealthy-nodes resource meta option to true and configures a recurring monitor interval of 10 seconds.

   # pcs resource create io-monitor ocf:pacemaker:HealthIOWait red_limit=15 op monitor interval=10s meta allow-unhealthy-nodes=true clone