15.3. Configuring Ticket Dependencies

⁠15.3. Configuring Ticket Dependencies

The rsc_ticket constraint lets you specify the resources depending on a certain ticket. Together with the constraint, you can set a loss-policy that defines what should happen to the respective resources if the ticket is revoked.

The attribute loss-policy can have the following values:

fence: Fence the nodes that are running the relevant resources.
stop: Stop the relevant resources.
freeze: Do nothing to the relevant resources.
demote: Demote relevant resources that are running in master mode to slave mode.

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Example 15.1. Constraint that fences node if ticketA is revoked

<rsc_ticket id="rsc1-req-ticketA" rsc="rsc1" ticket="ticketA" loss-policy="fence"/>

The example above creates a constraint with the ID rsc1-req-ticketA. It defines that the resource rsc1 depends on ticketA and that the node running the resource should be fenced if ticketA is revoked.

If resource rsc1 were a promotable resource (i.e. it could run in master or slave mode), you might want to configure that only master mode depends on ticketA. With the following configuration, rsc1 will be demoted to slave mode if ticketA is revoked:

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Example 15.2. Constraint that demotes rsc1 if ticketA is revoked

<rsc_ticket id="rsc1-req-ticketA" rsc="rsc1" rsc-role="Master" ticket="ticketA" loss-policy="demote"/>

You can create multiple rsc_ticket constraints to let multiple resources depend on the same ticket. However, rsc_ticket also supports resource sets (see Section 5.5, “Resource Sets”), so one can easily list all the resources in one rsc_ticket constraint instead.

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Example 15.3. Ticket constraint for multiple resources

<rsc_ticket id="resources-dep-ticketA" ticket="ticketA" loss-policy="fence">
  <resource_set id="resources-dep-ticketA-0" role="Started">
    <resource_ref id="rsc1"/>
    <resource_ref id="group1"/>
    <resource_ref id="clone1"/>
  </resource_set>
  <resource_set id="resources-dep-ticketA-1" role="Master">
    <resource_ref id="ms1"/>
  </resource_set>
</rsc_ticket>

In the example above, there are two resource sets, so we can list resources with different roles in a single rsc_ticket constraint. There’s no dependency between the two resource sets, and there’s no dependency among the resources within a resource set. Each of the resources just depends on ticketA.

Referencing resource templates in rsc_ticket constraints, and even referencing them within resource sets, is also supported.

If you want other resources to depend on further tickets, create as many constraints as necessary with rsc_ticket.