Core Resources
A cluster requires that a set of resources be online in order to operate. These resources are called the core resources, and consist of:
- An IP Address resource, an IPv6 Address resource, and/or an IPv6 Tunnel Address resource that provides the cluster IP address.
- A Network Name resource that provides the cluster name. This resource depends on the IP Address resource, IPv6 Address resource, and/or IPv6 Tunnel Address resource to create a failover cluster instance.
- A quorum resource that ensures cluster integrity and the persistence of accurate state information.
The core resources reside in a single group called (by default) the cluster group. The cluster group is created automatically during cluster setup.
If the core resources cannot be brought online, the cluster will not form and no resources in any group will be online. Therefore it is not necessary to create resources in the cluster group and set dependencies on the core resources in order to ensure that the cluster will be up and running before your resources are brought online.
In fact, there are good reasons for not creating resources in the cluster group. By default (as determined by the RestartAction property), if a resource fails the cluster initiates failover for the entire group. Failing over a group means taking all the resources in the group offline—which, for the core resources, means taking the cluster offline.
The cluster identifies the core resources by the CLUS_FLAG_CORE flag of the CLUS_FLAGS enumeration. For information on how to get the flags for a resource, see CLUSCTL_RESOURCE_GET_FLAGS.