9. Glossary

assign

In the scheduler, this refers to associating a resource with a node. Do not use allocate for this purpose.

bundle

The collective resource type associating instances of a container with storage and networking. Do not use container when referring to the bundle as a whole.

cluster layer

The layer of the cluster stack that provides membership and messaging capabilities (such as Corosync).

cluster stack

The core components of a high-availability cluster: the cluster layer at the “bottom” of the stack, then Pacemaker, then resource agents, and then the actual services managed by the cluster at the “top” of the stack. Do not use stack for the cluster layer alone.

CPG

Corosync Process Group. This is the messaging layer in a Corosync-based cluster. Pacemaker daemons use CPG to communicate with their counterparts on other nodes.

container

This can mean either a container in the usual sense (whether as a standalone resource or as part of a bundle), or as the container resource meta-attribute (which does not necessarily reference a container in the usual sense).

dangling migration

Live migration of a resource consists of a migrate_to action on the source node, followed by a migrate_from on the target node, followed by a stop on the source node. If the migrate_to and migrate_from have completed successfully, but the stop has not yet been done, the migration is considered to be dangling.

dependent

In colocation constraints, this refers to the resource located relative to the primary resource. Do not use rh or right-hand for this purpose.

IPC

Inter-process communication. In Pacemaker, clients send requests to daemons using libqb IPC.

message

This can refer to log messages, custom messages defined for a pcmk_output_t object, or XML messages sent via CPG or IPC.

metadata

In the context of options and resource agents, this refers to OCF-style metadata. Do not use a hyphen except when referring to the OCF-defined action name meta-data.

primary

In colocation constraints, this refers to the resource that the dependent resource is located relative to. Do not use lh or left-hand for this purpose.

primitive

The fundamental resource type in Pacemaker. Do not use native for this purpose.

score

An integer value constrained between -PCMK_SCORE_INFINITY and +PCMK_SCORE_INFINITY. Certain strings (such as PCMK_VALUE_INFINITY) parse as particular score values. Do not use weight for this purpose.

self-fencing

When a node is chosen to execute its own fencing. Do not use suicide for this purpose.