Sometimes there is a desperate need to change hostnames for one or all nodes of an Oracle RAC cluster. However, this operation is not officially supported. From Metalink Note 220970.1 RAC Frequently Asked Questions:
Can I change the public hostname in my Oracle Database 10g Cluster using Oracle Clusterware?
Hostname changes are not supported in Oracle Clusterware (CRS), unless you want to perform a deletenode followed by a new addnode operation.
The hostname is used to store among other things the flag files and CRS stack will not start if hostname is changed.
One way to do it is to remove a node from a cluster, change its hostname, and then add it back to the cluster as a new node. You will need to make sure that ORACLE_HOME is also added to this node as well as the database instance configuration.
If you are brave enough, there is another way to do this. It’s not described anywhere on the Metalink, but there are no major hacks needed to implement it. The idea is to simply re-run the configuration of CRS (including re-formatting OCR and voting disks) and re-create the CRS resources after that. Obviously, this is not an online operation and the whole cluster is down for the duration of rename.
I assume that we have an Oracle RAC cluster running, with database(s) running already, optionally including ASM instances.
