Installation guide

A cluster service is an integrated entity that runs under the control of rgmanager. All resources in a

service run on the same node. From the perspective of rgmanager, a cluster service is one entity that

can be started, stopped, or relocated. Within a cluster service, however, the hierarchy of the

resources determines the order in which each resource is started and stopped.The hierarchical levels

consist of parent, child, and sibling.

Example D.1, “ Resource Hierarchy of Service foo” shows a sample resource tree of the service foo. In

the example, the relationships among the resources are as follows:

fs:myfs (<fs name="myfs" ...>) and ip:10.1.1.2 (<ip address=" 10.1.1.2 .../>) are siblings.

fs:myfs (<fs name="myfs" ...>) is the parent of script:script_child (<script

name="script_child" />).

script:script_child (<script name="script_child"/>) is the child of fs:myfs (<fs

name="myfs" ...>).

Example D.1. R eso u rce Hierarch y of Service f o o

</fs>

</service>

The following rules apply to parent/child relationships in a resource tree:

Parents are started before children.

Children must all stop cleanly before a parent may be stopped.

For a resource to be considered in good health, all its children must be in good health.

D.2. Sibling St art Ordering and Resource Child Ordering

The Service resource determines the start order and the stop order of a child resource according to

whether it designates a child-type attribute for a child resource as follows:

Designates child-type attribute (typed child resource) — If the Service resource designates a child-

type attribute for a child resource, the child resource is typed. The child-type attribute explicitly

determines the start and the stop order of the child resource.

Does not designate child-type attribute (non-typed child resource) — If the Service resource does not

designate a child-type attribute for a child resource, the child resource is non-typed. The Service

resource does not explicitly control the starting order and stopping order of a non-typed child

resource. However, a non-typed child resource is started and stopped according to its order in

/etc/cluster/cluster.conf In addition, non-typed child resources are started after all typed

child resources have started and are stopped before any typed child resources have stopped.

Note

The only resource to implement defined child resource type ordering is the Service resource.

HA Resou rce Behavior

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