Chapter 4. Configuring Pacemaker
Pacemaker’s configuration, the CIB, is stored in XML format. Cluster administrators have multiple options for modifying the configuration either via the XML, or at a more abstract (and easier for humans to understand) level.
Pacemaker reacts to configuration changes as soon as they are saved. Pacemaker’s command-line tools and most higher-level tools provide the ability to batch changes together and commit them at once, rather than make a series of small changes, which could cause avoid unnecessary actions as Pacemaker responds to each change individually.
Pacemaker tracks revisions to the configuration and will reject any update older than the current revision. Thus, it is a good idea to serialize all changes to the configuration. Avoid attempting simultaneous changes, whether on the same node or different nodes, and whether manually or using some automated configuration tool.
It is not necessary to update the configuration on all cluster nodes. Pacemaker immediately synchronizes changes to all active members of the cluster. To reduce bandwidth, the cluster only broadcasts the incremental updates that result from your changes and uses checksums to ensure that each copy is consistent.
4.1. Configuration Using Higher-level Tools
Most users will benefit from using higher-level tools provided by projects separate from Pacemaker. Some of the most commonly used include the crm shell, hawk, and pcs.
See those projects' documentation for details on how to configure Pacemaker using them.
