4.8. Cluster Maintenance
4.8. Cluster Maintenance In order to perform maintenance on the nodes of your cluster, you may need to stop or move the resources and services running on that cluster. Or you may need to stop the cluster software while leaving the services untouched. Pacemaker provides a variety of methods for performing system maintenance. If you need to stop a node in a cluster while continuing to provide the services running on that cluster on another node, you can put the cluster node in standby mode. A node that is in standby mode is no longer able to host resources. Any resource currently active on the node will be moved to another node, or stopped if no other node is eligible to run the resource. For information on standby mode, see Section 4.4.5, "Standby Mode" . If you need to move an individual resource off the node on which it is currently running without stopping that resource, you can use the pcs resource move command to move the resource to a different node. For information on the pcs resource move command, see Section 8.1, "Manually Moving Resources Around the Cluster" . When you execute the pcs resource move command, this adds a constraint to the resource to prevent it from running on the node on which it is currently running. When you are ready to move the resource back, you can execute the pcs resource clear or the pcs constraint delete command to remove the constraint. This does not necessarily move the resources back to the original node, however, since where the resources can run at that point depends on how you have configured your resources initially. You can relocate a resource to a specified node with the pcs resource relocate run command, as described in Section 8.1.1, "Moving a Resource from its Current Node" . If you need to stop a running resource entirely and prevent the cluster from starting it again, you can use the pcs resource disable command. For information on the pcs resource disable command, see Section 8.4, "Enabling, Disabling, and Banning Cluster Resources" . If you want to prevent Pacemaker from taking any action for a resource (for example, if you want to disable recovery actions while performing maintenance on the resource, or if you need to reload the /etc/sysconfig/pacemaker settings), use the pcs resource unmanage command, as described in Section 8.6, "Managed Resources" . Pacemaker Remote connection resources should never be unmanaged. If you need to put the cluster in a state where no services will be started or stopped, you can set the maintenance-mode cluster property. Putting the cluster into maintenance mode automatically unmanages all resources. For information on setting cluster properties, see Table 12.1, "Cluster Properties" . If you need to perform maintenance on a Pacemaker remote node, you can remove that node from the cluster by disabling the remote node resource, as described in Section 9.4.8, "System Upgrades and pacemaker_remote" .