Serviceguard Node Name Change

[mark quinn_2]

Customer wants node names changed on cluster nodes. How much work would be involved in changing the node names of the servers in a 2 node cluster. How much time do you think this would take approx. ?

[Chan 007]

Depends on the SA skilks, and whether DNS names is maintained only in Unix side or even other use the same node name in DNA for outside world.

It will take about 1 days (8 hours), I also say that you have more time to have one normal failover/failback tast carried out prior to handing to Production.

Also check that any script or DBA's use this node name for their listener or so. If so then need to work on this.

Chan

[Warren_9]

hi,

i think u need to change the host/node info in the following files.

1. /etc/hosts OR DNS
2. /etc/cmcluster/cmclnodelist
3. /etc/cmcluster/cmclconfig.ascii
4. package configure ascii

so, the step will be
1. halt the cluster
2. remove the old config <-- cmdeleteconf
3. apply change the above file
4. apply the new config.

the step should less than an hr.

Hope this can help... GOOD LUCK!!

[David de Beer]

It all depends on how complex your cluster configuration is?

How many Volume Groups do you have configured to fail-over? How many packages?

We have some clusters that you can do a cmapplyconf and it takes 2 minutes. These clusters have little failover disks, max maybe 50 disks and 2 volume groups. Then we have another cluster with 30 VG's and probably 900 disks and their ALT's. The cmapplyconf takes over an hour to complete.

Can you give us more details on the current cluster setup?

Regards,
David.

[Stephen Doud]

The server's hostname is embedded in the cluster binary file (use cmviewconf to see it). The hostname can be changed by removing the node from the cluster and re-adding it (this can be done online, while the rest of the cluster is operating) or the cluster can be halted, and cmapplyconf the updated cluster configuration file.
Each method takes different amounts of time. I can't estimate how long, because of admin skill level and potential errors.
Please read this document:
UMCSGKBRC00006541
TITLE: Changing HOSTNAME on a ServiceGuard node

[Rita C Workman]

...another thing to remember, just as Stephen pointed out that SG embeds the nodename within it's software..so do other things.
So before you go changing things, you need to 'know' what other software could be impacted by the change.

Before you start, spend enough time researching and planning. Like Stephen pointed out, you could easily remove a node from a cluster, with the cluster running and then add it back as a new node.

Always....be sure what the ramifications are of changing a nodename or an IP before you start.

Just a thought,
Rita