Installation guide

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

service run on the same node. From the perspective of rg manag er, 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 C.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 i p: 10 . 1. 1. 2 (<ip address=" 10.1.1.2 .../>) are siblings.

fs: myfs (<fs name="myfs" ...>) is the parent of scri pt: scri pt_chil d (<script

name="script_child"/>).

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

name="myfs" ...>).

Examp le C.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.

Note

When configuring a dependency tree for a cluster service that includes a floating IP address

resource, you must configure the IP resource as the first entry and not as the child of another

resource.

C.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

HA Resource Behavior

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