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6.3. Specifying the Order in which Resources Should Start/Stop

Ordering constraints tell the cluster the order in which resources should start.


Ordering constraints affect only the ordering of resources; they do not require that the resources be placed on the same node. If you want resources to be started on the same node and in a specific order, you need both an ordering constraint and a colocation constraint (see Section 6.4, “Placing Resources Relative to other Resources”), or alternatively, a group (see Section 10.1, “Groups - A Syntactic Shortcut”).

6.3.1. Ordering Properties

Table 6.2. Properties of a rsc_order Constraint

Field Default Description
A unique name for the constraint
Name of the resource that the then resource depends on
Name of the dependent resource
The action that the first resource must complete before then-action can be initiated for the then resource. Allowed values: start, stop, promote, demote.
value of first-action
The action that the then resource can execute only after the first-action on the first resource has completed. Allowed values: start, stop, promote, demote.
How to enforce the constraint. Allowed values:
  • Optional: Just a suggestion. Only applies if both resources are executing the specified actions. Any change in state by the first resource will have no effect on the then resource.
  • Mandatory: Always. If first does not perform first-action, then will not be allowed to performed then-action. If first is restarted, then (if running) will be stopped beforehand and started afterward.
  • Serialize: Ensure that no two stop/start actions occur concurrently for the resources. First and then can start in either order, but one must complete starting before the other can be started. A typical use case is when resource start-up puts a high load on the host.
If true, the reverse of the constraint applies for the opposite action (for example, if B starts after A starts, then B stops before A stops).

Promote and demote apply to the master role of multi-state resources.