Changing the host name for a cluster node in PowerHA SystemMirror

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You can use PowerHA® SystemMirror® to change the host name for a node while cluster services are active.

About this task

Cluster Aware AIX® (CAA) uses the host name as a point of reference for cluster communication. PowerHA SystemMirror stores the IP address that is associated with a host name in a configuration database. Therefore, you must consider the effect of each type of host name change (permenant or temporary) and whether the PowerHA SystemMirror configuration requires an update to reflect a host name change.

With AIX interfaces, you can change a host name temporarily or permanently. If you change a host name by using either method, the host name must resolve to a TCP/IP address.

If you change the host name temporarily, the host name is updated in the AIX kernel but not in the AIX Object Data Manager (ODM). If you use the temporary host name change method, the host name is not saved when the system reboots.

If you change the host name permanently, the host name is updated in the AIX kernel and in the AIX Object Data Manager (ODM). If you use the permanent host name change method, the new host name is used after the system reboots.

Review the following information before you change the host name for a cluster node in PowerHA SystemMirror:
  • Do not change the host name of the cluster nodes during initial cluster configuration.
  • Do not change the host name of the cluster nodes when you are migrating from a prior version of PowerHA SystemMirror.
  • Do not change the host name on multiple nodes in the cluster at the same time. If you change the host name for multiple nodes, change it on one node at a time and synchronize the cluster configuration after each change.
You can use one of the following methods to change a host name for a cluster node in PowerHA SystemMirror:
Temporary host name change
You can use the hostname command to change the host name for the node. By default, PowerHA SystemMirror and CAA ignore this type of change and the PowerHA SystemMirror configuration database is not updated.
Permanent host name change
From the command line, enter smitty hostname and use the SMIT interface to change the host name. When you change the host name with this method, PowerHA SystemMirror responds by updating the configuration database with new host name information. After you complete the changes, you must verify and synchronize the cluster.