What happens when a node rejoins a cluster ?

[Herdip Kalare_1]

When a node rejoins a cluster, should I expect to have to run a cmrunode to activate a node, or should the fact that I have the AUTOSTART_CMCLD parameter set correctly ensure that the node comes back as an active member of the cluster ?

[Jeff Schussele]

Hi,

If you have AUTOSTART_CMCLD=1 in the /etc/rc.config.d/cmcluster file then upon bootup the node will autonatically rejoin the cluster & if it's primary package(s) are not running elsewhere they will start up upon it.

Rgds,
Jeff

[Bernhard Mueller]

Hi,

as you suspect, if AUTOSTART_CMCLD is set to 1 in /etc/rc.config.d/cmcluster, a cmrunnode is exectuted and the node tries to join the cluster.

(It is expected that the cluster is running at least on one node).

If you set it to 0, you will have to manually enter cmrunnode after reboot in order to join the cluster, in any case this does not affect the status of any package.

Regards,
Bernhard

[George_Dodds · Accepted solution]

Hi Herdip.

Did you use to be an VM/OS390 bloke?

Yup the node will automatically come back as an actice member.

Ta

George

[Herdip Kalare_1]

This is what I thought. However, after having applied patches to a node which is part of a 2 node cluster, the server was rebooted and did not fully rejoin the cluster. A cmrunnode command was required before packages were able to run on the node. Any ideas ?

[Jeff Schussele]

Hi Herdip,

Check the syslog.log files on the cluster nodes including the node that didn't rejoin. It will tell you what happened & should explain why it failed to join the cluster.

Rgds,
Jeff

[Herdip Kalare_1]

Is that George who use to work at TNT ?

My AUTOSTART_CMCLD is set appropriately, but the node did not fully rejoin the cluster.

[Bernhard Mueller]

Hi,

what do you mean with "full" rejoin. Over time in cmviewcl the node is either "down" or "up". Or does it remain in "starting"?

Regards,
Bernhard

[Stephen Doud]

Please see this document for a discussion about cluster reformation at boot time:
http://www1.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000062686678

It gives a detailed description of the concepts and even of why a node will not join a cluster even
though AUTOSTART_CMCLD=1.

=StephenD.