Change hostnames oracle RAC

I would like to change hostnames in oracle RAC.

on Metalink (NOTE:220970.1)

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 Oracle Clusterware stack will not start if hostname is changed.

Anyway I found out on internet, I found idea on this site

http://www.pythian.com/blogs/482/changing-hostnames-in-oracle-rac

I like it; From step by step that make me understood and created my step.

this's my step example:

- Capture Resource.

Example script:

mkdir /tmp/resources && for x in `$ORA_CRS_HOME/bin/crs_stat -p  | grep "^NAME=" |awk -F\= '{print $2}'` ; do

    $ORA_CRS_HOME/bin/crs_stat -p $x >/tmp/resources/$x.cap

done

- Stop Cluster every nodes.

$ORA_CRS_HOME/bin/crsctl stop crs

- Change hostnames / (/etc/hosts files) / DNS for every nodes 

- Modified $ORA_CRS_HOME/install/rootconfig (on every nodes)

On variables:

CRS_HOST_NAME_LIST

CRS_NODE_NAME_LIST

CRS_PRIVATE_NAME_LIST

CRS_NODELIST

CRS_NODEVIPS

from "old_hosts" to "ew_hosts"

If use 11G 

should to modified on paramfile.crs file as well.

- Cleanup OCR and Voting Disks

on $ORA_CRS_HOME/install/rootconfig and $ORA_CRS_HOME/install/paramfile.crs (11G) files:

CRS_OCR_LOCATIONS={file},{file}

CRS_VOTING_DISKS={file},{file},{file}

dd if=/dev/zero of={file} bs=1024k

- Run rootconfig script (on every nodes)

$ORA_CRS_HOME/install/rootconfig 

(If Error):

No value set for the CRS parameter CRS_OCR_LOCATIONS. Using Values in paramfile.crs

Checking to see if Oracle CRS stack is already configured

Oracle CRS stack is already configured and will be running under init(1M)

rootconfig script was protected some...

So, remove /etc/oracle/ocr.loc

and run again!

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Expecting the CRS daemons to be up within 600 seconds.

Cluster Synchronization Services is active on these nodes. 

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Cluster Synchronization Services is active on all the nodes. 

Oracle CRS stack installed and running under init(1M)

Running vipca(silent) for configuring nodeapps

Creating VIP application resource on (1) nodes..

Creating GSD application resource on (1) nodes..

Creating ONS application resource on (1) nodes..

Starting VIP application resource on (1) nodes..

Starting GSD application resource on (1) nodes..

Starting ONS application resource on (1) nodes..

- Verify status.

$ORA_CRS_HOME/bin/crs_stat -t

- Register Listener + ASM + Database + Service to CRS.

use netca for listener or srvctl command-line or crs_register.

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And final check that make sure every things working.