High Availability and Clusters

The following features, enhancements, and changes related to high availability are introduced in this Oracle Linux 9 release.

pcs cluster rename Command Available for Renaming Clusters

Clusters can be renamed with the pcs cluster rename <new-name> command, reducing the need for manual steps. The command updates all relevant cluster properties so the cluster continues working seamlessly after the rename.

fence_sbd Agent Automatically Detects SBD Devices

The fence_sbd agent can automatically retrieve the SBD device configuration if you don't explicitly specify the SBD device path when using the devices parameter. If you omit the parameter, the agent gets the configuration from the SBD_DEVICE variable in /etc/sysconfig/sbd.

This enhancement simplifies fencing setup in Pacemaker clusters that use SBD, reduces configuration errors, and streamlines deployment for standard setups.

pcs Warns Users Before Removing the Last Fencing Device

pcs prevents accidental removal of the last cluster fencing mechanism, displaying an error message to avoid leaving the cluster in an unsupported state. For example: 

Error: Requested action lefts the cluster with no enabled means to fence nodes, 
resulting in the cluster not being able to recover from certain failure conditions, 
use --force to override

If you use the --force option, you can override the block on this action, but a warning message is displayed: 

Warning: Requested action lefts the cluster with no enabled means to fence nodes, 
resulting in the cluster not being able to recover from certain failure conditions
Warning: Resources are not going to be stopped before deletion, this may result in 
orphaned resources being present in the cluster

The IPaddr2 resource agent checks the link state of network interfaces and correctly handles failover if a network interface is down, improving cluster reliability. This feature is enabled by default.

Administrators can disable link monitoring and automatic failover by setting check_link_status=false in the resource configuration.

pcs node attribute and pcs node utilization Commands Include Multiple Output Formats

Node attribute and utilization reporting in pcs now include text, json, and cmd output formats for easier scripting and automation. Use the --output-format option with pcs node commands to set the output that you need.

pcs alert config Provides Multiple Output Formats

The pcs alert config subcommand provides text, json, and cmd output formats, which can be controlled by using the --output-format option. JSON and command output make alert configuration easier to automate and replicate.