Introduction

Renaming an Oracle RAC cluster is not an easy thing, unfortunately for me I had to do this today because the name chosen for the newly installed cluster was wrong.
Oracle does not provide a simple command to do this and you have to go through a deconfiguration/reconfiguration of the whole cluster.

Changing the cluster name

Deconfigure RAC (root user)

On each node except the last one as user root:

<GRID_HOME>/crs/install/rootcrs.pl -deconfig -force -verbose

On the last node as root:

<GRID_HOME>/crs/install/rootcrs.pl -deconfig -force -verbose -lastnode

Cleanup the ASM disks (grid user)

You need to cleanup the ASM disks used for the OCR diskgroup because the diskgroup cannot be reused.

dd if=/dev/zero of=/dev/rhdisk2asm bs=1024k count=50
dd if=/dev/zero of=/dev/rhdisk3asm bs=1024k count=50
dd if=/dev/zero of=/dev/rhdisk4asm bs=1024k count=50

Reconfigure RAC (grid user)

To reconfigure the cluster you just restart the setup of the grid installation, either config.sh for 11g or gridSetup.sh for 12c. I used the responsefile from my first installation and just edited the response file to change my cluster name.

<GRID_HOME>/crs/config/gridSetup.sh -silent -responsfile /home/oracle/grid.rsp -silent -responsfile /home/oracle/grid.rsp

Execute root.sh scripts once installation completes as instructed by the installer.

Check if the change is effective

/opt/oracle/grid/12.2.0.1.0/bin/olsnodes -c

Additionnal Steps

if you already had created a database on the cluster before changing its name, here are the additionnal steps you need to perform.

Mount the ASM diskgroups

SQL> alter diskgroup FRA mount;

Diskgroup altered.

SQL> alter diskgroup DATA12 mount;

Diskgroup altered.

Add back the database to the cluster

srvctl add database -db MYBD -oraclehome /opt/oracle/base/bd/12.2.0.1/ -dbtype RAC -spfile +DATA12/MYBD/PARAMETERFILE/spfile.275.987328111 -pwfile +DATA12/MYBD/PASSWORD/pwdmybd.256.987327363

Add instances to the database

srvctl add instance -db MYBD -i INST1 -n node1
srvctl add instance -db MYBD -i INST2 -n node2
srvctl add instance -db MYBD -i INST3 -n node3

Start the database

srvctl start database -db MYBD

Reference: Doc ID 1967916.1