Serviceguard
cancel
Showing results for 
Search instead for 
Did you mean: 

Three node cluster to be made in two

 
zxcv
Super Advisor

Three node cluster to be made in two

Hi ,

 

We have a 3 node ( A,B,C )  cluster hpux 11iv2 , Serviceguard 11.18 .

Out of which we have decided to change one servers ip ( Node A )  from X to Y.

Have listed some steps below ;

 

  1. Change /etc/rc.config.d/cmcluster=0 in node A
  2. cmhaltpackages
  3. cmhaltnode Node A
  4. set_parms ip_address
  5. Reboot

Now after this change , what changes i have to make in other two nodes so that when they reboot/panic my cluster doesnt keep looking for this Node A.

Also i have to assign NODE A ip to a different server in same LAN.

 

1 REPLY 1
Matti_Kurkela
Honored Contributor

Re: Three node cluster to be made in two

Your thread title suggests you're planning to reduce your cluster from 3 nodes to 2. Is this correct, or are you planning to add Node A back using its new IP address?

 

Before removing a node from the cluster, you must first remove all references to it from the package configurations. Otherwise the cmapplyconf command will reject the new cluster configuration.

 

It is better to cleanly remove the node from the cluster configuration while it is still reachable using the old IP address: this way the configuration tools can remove the configuration information from the node that is being removed, and the other nodes will receive a confirmation that the node is cleanly removed.

 

My procedure would be:

  1. on node A, change /etc/rc.config.d/cmcluster=0
  2. halt all packages running on node A (you can restart them on other nodes if you want)
  3. use cmgetconf -p <packagename> <packagename>.ascii to get ASCII versions of the package configuration files
  4. remove all references to node A from the ASCII package configuration files
  5. use cmapplyconf -P to apply any package configuration files modified in step 4
  6. cmhaltnode node A
  7. use cmgetconf <clustername>.ascii to get an ASCII version of the cluster configuration file
  8. remove/comment out node A from the cluster ASCII configuration file
  9. use cmapplyconf -C to apply the new cluster ASCII configuration file
  10. now all nodes know that node A is completely detached from the cluster, you can do whatever you want to it.

If you plan to re-introduce node A to the cluster with its new IP address, first add it back to cluster configuration and run cmapplyconf -C. Once that is successful, you can again modify the package configurations to add node A back to the list of allowed nodes for each package, if necessary.

MK