High Availability and Clusters

The following features, enhancements, and changes related to high availability are introduced in this Oracle Linux 10 release.

Pacemaker Released at Version 2.1.8

Pacemaker is released at version 2.1.8.

pcs status wait Command Added

Pacemaker includes the pcs status wait command that ensures that Pacemaker completes any actions required by changes to the Cluster Information Base (CIB). It ensures that no further actions are required to make the actual cluster state match the requested cluster state.

--output-format Option Available for pcs Commands

The --output-format option is added to various pcs commands, to display output in different formats. The option accepts the following values:

  • text: displays output in plain text,

  • cmd: displays output as pcs commands to re-create the configuration,

  • json: displays output in JSON format for machine parsing.

The --output-format option can be used with the pcs tag command to display configured tags. For example: 

pcs tag --output-format cmd

HA Cluster Management Web UI

The standalone pcsd Web UI is replaced with a Cockpit web console add-on called the HA Cluster Management application. The HA Cluster Management application can be used to create and manage high-availability clusters using Pacemaker and Corosync from within the Cockpit web console. Features include graphical tools to perform tasks such as configuring cluster nodes, managing resources, and setting up fencing devices.

Documentation for the HA Cluster Management application is covered in Oracle Linux 10: Setting Up High Availability Clustering.

pcs Validation on Resource Creation and Update

By default, pcs instructs the resource agent to validate the parameters you enter when you create or update a cluster resource. For backward compatibility, if you enter an invalid parameter, a warning appears that doesn't prevent entering the invalid parameter. To prevent invalid parameter entry, specify the --agent-validation parameter.

pcs Confirmation Option For Destructive Actions

The pcs command includes a --yes option that confirms destructive actions, such as destroying a cluster or unblocking quorum. This update separates this functionality from the --force option, which is used to override validation errors.

pcs Command to Query the Status of Resources

You can use the pcs status query resource command to query various attributes of a single resource in a cluster, such as its existence, type, and state. The command returns plain text outputs for each of the resource attributes that you query.

Pacemaker Configuration Option to Leave a Panicked Node Shut Down

Set the PCMK_panic_action variable in the /etc/sysconfig/pacemaker configuration file to off or sync-off so that a node remains shut down after a panic condition instead of rebooting automatically.

Deleting Several Resources With a Single pcs Command

You can now specify several resources at the same time when using the pcs resource delete, pcs resource remove, pcs stonith delete, and pcs stonith remove commands, so that you don't have to run the command repeatedly for each resource that you want to remove.

For example, you can run:

pcs resource delete service2 service3

Creating Globally Unique Cluster Resource Clones

To configure a cluster resource clone to be globally unique, you can configure the clone option clone-node-max > 1 when creating the clone of an existing resource or resource group. You also don't need to use the globally-unique="true" option when cloning resources or resource groups.

Updated Date Specification and Duration Options in Pacemaker Rules

Pacemaker rules are updated with new date specification and duration options. The following options are removed:

  • monthdays, moon, weekdays, weekyears, and yearsdays from the duration options.

  • moon and yearsdays from the date-spec options.

The following new options are available:

  • The duration options are seconds, minutes, hours, days, weeks, months, and years.

  • The date-spec options are seconds, minutes, hours, monthdays, weekdays, yeardays, months, weeks, years, and weekyears.

You can configure rules that incorporate these new duration and date-spec options in the following pcs resource defaults and pcs resource op defaults commands and their aliases, pcs stonith defaults and pcs stonith op defaults. The options also apply to the pcs constraint location command.