6.3.3. Colocating Sets of Resources

If your configuration requires that you create a set of resources that is colocated and started in order, you can configure a resource group that contains those resources, as described in Section 5.5, “Resource Groups”. If, however, you need to colocate a set of resources but the resources do not necessarily need to start in order, you can create a colocation constraint on a set or sets of resources with the pcs constraint colocation set command.
You can set the following options for a set of resources with the pcs constraint colocation set command.
  • sequential, which can be set to true or false to indicate whether the members of the set must be colocated with each other.
    Setting sequential to false allows the members of this set to be colocated with another set listed later in the constraint, regardless of which members of this set are active. Therefore, this option makes sense only if another set is listed after this one in the constraint; otherwise, the constraint has no effect.
  • role, which can be set to Stopped, Started, Master, or Slave. For information on multi-state resources, see Section 8.2, “Multi-State Resources: Resources That Have Multiple Modes”.
You can set the following constraint options for a set of resources following the setoptions parameter of the pcs constraint colocation set command.
  • kind, to indicate how to enforce the constraint. For information on this option, see Table 6.2, “Properties of an Order Constraint”.
  • symmetrical, to indicate the order in which to stop the resources. If true, which is the default, stop the resources in the reverse order. Default value: true
  • id, to provide a name for the constraint you are defining.
When listing members of a set, each member is colocated with the one before it. For example, "set A B" means "B is colocated with A". However, when listing multiple sets, each set is colocated with the one after it. For example, "set C D sequential=false set A B" means "set C D (where C and D have no relation between each other) is colocated with set A B (where B is colocated with A)".
The following command creates a colocation constraint on a set or sets of resources.
pcs constraint colocation set resource1 resource2 [resourceN]... [options] [set resourceX resourceY ... [options]] [setoptions [constraint_options]]