Remove node from Cluster

[Filosofo]

Hello I have Service Guard 11.14 on Hpux11i, I would remove a node from configuration.....What Can I do?
My cluster have two node.......Can live the cluster with only one node?

I hope that you can help me.

Filo

[Jeff Schussele]

Hi Filo,

This is fairly straightforward & easy.
Shouldn't even have to take a pkg down (if it's not running on the node to be removed) or the cluster itself.
You do the following;

1) Remove the node from ALL pkgs by editing the pkg conf file & apply the new configuration:

cmapplyconf -f -v -k -P /etc/cmcluster/pkg_name/pkg_name.conf

2) Halt cluster services on the node to be removed

cmhaltnode -n node_name

3) Remove the node from the cluster config by editing it out of the cluster conf file & apply the new configuration.

cmapplyconf -f -v -K -C /etc/cmcluster/cluster_name.conf

Then just check the cluster with a cmviewcl to verify that it's no longer in the cluster.
And yes - you can have a single node cluster, but you lose the ability to fail it over. All you can do now is monitor the app & restart it if it fails or failover a NIC on that box.

HTH,
Jeff

[Jeff Schussele]

Oops - no -n in that cmhaltnode command - just:

cmhaltnode node_name

You can use -f to force the halt and you can use -v for verbose, but no -n.

Rgds,
Jeff

[Uday_S_Ankolekar]

cmhaltnode nodename should do this but then your entire purpose of having service guard is not achieved since you have only two nodes in the cluster!

No need to halt cluster.

-USA..

[Martin Johnson]

Uday,

That is not ture. A single node cluster is not only viable but can be beneficial. My packages are set up to automatically restart any application with the package if it goes down.

The restart limit is set to ten. So SG will do this up to ten times. This is quite helpful when an appliction goes down due to a network glitch or some other non-recurring problem. No manual intervention and a minimal amount of downtime.

You have to set up the package to not automatically restart apps if a maintenance flag is present. This maintnenace flag allows you to bring down the apps and keep them down while you do maintenance.

HTH
Marty