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

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

Important

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”).

Table 6.2. Properties of a rsc_order Constraint

Field	Default	Description
`id`		A unique name for the constraint
`first`		Name of the resource that the `then` resource depends on
`then`		Name of the dependent resource
`first-action`	start	The action that the `first` resource must complete before `then-action` can be initiated for the `then` resource. Allowed values: `start`, `stop`, `promote`, `demote`.
`then-action`	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`.
`kind`		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.
`symmetrical`	TRUE	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.