2.4. Considerations for Configuring HA Services

2.4. Considerations for Configuring HA Services

A cluster service is a group of cluster resources configured into a coherent entity that provides specialized services to clients. A cluster service is represented as a resource tree in the cluster configuration file, /etc/cluster/cluster.conf (in each cluster node). In the cluster configuration file, each resource tree is an XML representation that specifies each resource, its attributes, and its relationship among other resources in the resource tree (parent, child, and sibling relationships).


Because a service consists of resources organized into a hierarchical tree, a service is sometimes referred to as a resource tree or resource group. Both phrases are synonymous with cluster service.

At the root of each resource tree is a special type of resource — a service resource. Other types of resources comprise the rest of a service, determining its characteristics. Configuring a cluster service consists of creating a service resource, creating subordinate cluster resources, and organizing them into a coherent entity that conforms to hierarchical restrictions of the service.

There are two major considerations to take into account when configuring a cluster service:

The types of resources and the hierarchy of resources depend on the type of service you are configuring.

The types of cluster resources are listed in Appendix C, HA Resource Parameters. Information about parent, child, and sibling relationships among resources is described in Appendix D, HA Resource Behavior.

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