If exclusive relationships for the cluster applications are set up, the cluster applications with exclusive relationships can be prevented from operating simultaneously in one cluster node. An exclusive relationship can be set up only between standby cluster applications. If failover occurs, determine the cluster applications that should continue operating by using the job priority of the cluster applications between which an exclusive relationship is set.
Exclusive control is established between cluster applications within a single group.
Information
To set up an exclusive relationship, create a group of cluster applications between which an exclusive relationship is to be set. Up to 52 groups can be created.
For information on setting up an exclusive relationship, see "6.7.2.1 Creating Standby Cluster Applications."
The cluster application in which the exclusive relationship is set transits to Standby state according to the StandbyTransitions attribute.
Note
When the cluster application state is Faulted on a node, cluster applications in exclusive relationships on that node cannot be made operational by newly starting the cluster applications. Cluster applications started later will be stopped regardless of job priority.
The reason for this is that possibly not all resources under the control of the cluster application in the Faulted state could be stopped.
In such a case, clear the Faulted state of the cluster application to bring it to the Offline state, and then start the cluster applications that are in exclusive relationships.
For information on how to clear the Faulted state of cluster application, see "7.2.2.4 Bringing Faulted Cluster Application to available state."
The operation of cluster applications, between which an exclusive relationship is set up, during failover can be explained in the following two cases:
When the job priorities are different
When the job priorities are the same
The example below explains the exclusive relationship between cluster applications within a single group. Even when there are multiple groups, the operation within a single group is the same.
When the job priorities of the cluster applications with an exclusive relationship are different
Cluster applications with the highest job priority take the top priority for startup on the nodes on which the cluster applications with high job priority are running or on the nodes to which the cluster applications with high job priority are failed over. Therefore, cluster applications running with low priorities will be forcibly exited.
The states indicated in the following figure are as follows:
OPERATING: The cluster application is in the Online state.
STANDBY: The cluster application is in the Standby state.
STOP: The cluster application is in the Offline state.
Failover of the cluster application with a high job priority
If failover occurs in a cluster application with a high job priority, the cluster application with the high job priority will always be in the operating state.
Failover of the cluster application with a low job priority
Failover occurs for a cluster application with a low job priority only when there is no cluster application with a high job priority included on the node to which the cluster application with a low job priority is to be failed over.
When the job priorities of cluster applications with an exclusive relationship are the same
The operation of the cluster applications that are already running will be continued. On the node on which cluster applications are already running, cluster applications that subsequently start up will be stopped.
