Product SiteDocumentation Site Constraints

In most cases, a clone will have a single copy on each active cluster node. However if this is not the case, you can indicate which nodes the cluster should to preferentially assign copies to with resource location constraints. These constraints are written no differently to those for regular resources except that the clone's id is used.
Ordering constraints behave slightly differently for clones. In the example below, apache-stats will wait until all copies of the clone that need to be started have done so before being started itself. Only if no copies can be started will apache-stats be prevented from being active. Additionally, the clone will wait for apache-stats to be stopped before stopping the clone.
Colocation of a regular (or group) resource with a clone means that the resource can run on any machine with an active copy of the clone. The cluster will choose a copy based on where the clone is running and the rsc resource's own location preferences.
Colocation between clones is also possible. In such cases, the set of allowed locations for the rsc clone is limited to nodes on which the with clone is (or will be) active. Allocation is then performed as-per-normal.
Example 10.5. Example constraints involving clones

    <rsc_location id="clone-prefers-node1" rsc="apache-clone" node="node1" score="500"/>
    <rsc_colocation id="stats-with-clone" rsc="apache-stats" with="apache-clone"/>
    <rsc_order id="start-clone-then-stats" first="apache-clone" then="apache-stats"/>