Cluster Down vs. Packages Down

[Steve Bonds]

Is it possible to bring down the ServiceGuard cluster software for parameter changes while the packages/applications remain running?

On pg 211 of the Managing ServiceGuard manual the "cmhaltcl -f -v" command is described where "-f" will halt the cluster even when packages are running. However, it doesn't mention if the packages will remain running after the halt or what steps are needed (if any) aside from the "cmruncl -v" to restart the cluster.

Obviously while the cluster is not running there can be no package failover. I just want to know if I need to have all packages down for a cluster parameter change.

[Sanjay_6]

Hi Steve,

In a muti-node cluster, you can bring one node down while the package is still running on the adoptive node.

Have a look at this for the jobs you can do while reconfiguring a cluster.

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B3936-90045/B3936-90045_top.html&con=/hpux/onlinedocs/B3936-90045/00/00/49-con.html&toc=/hpux/onlinedocs/B3936-90045/00/00/49-toc.html&searchterms=reconfiguring&queryid=20011001-120235

Hope this helps.

thanks

[linuxfan]

Hi Steve,


It depends on which parameter you are trying to change.

This link tells you what changes you can while the cluster is up and running

http://docs.hp.com/cgi-bin/onlinedocs.py?mpn=B3936-90045&service=hpux&path=../B3936-90045/00/00/49&title=Managing%20MC/ServiceGuard

This link tells you what changes you can do while the package is running.
http://docs.hp.com/cgi-bin/onlinedocs.py?mpn=B3936-90045&service=hpux&path=../B3936-90045/00/00/51&title=Managing%20MC/ServiceGuard

-HTH
Ramesh

[Santosh Nair_1 · Accepted solution]

The cmhaltcl -vf will halt all of the packages in the cluster and then stop the cluster...so basically, this takes down everything. Also, as Ramesh mentions, some cluster parameters do not require taking the cluster down. But for the ones that need the cluster to be down, you'd need to take all the nodes in the cluster down.

-Santosh

[Steve Bonds]

I'm concerned with the parameters which require the cluster to be down.

So far it sounds like all packages need to be down for these changes.

[linuxfan]

Hi Steve,

If you are modifying a parameter which needs the cluster to be down, that means you have to halt all the packages (cmhaltpkg) and then bring the cluster down cmhaltcl.

Once you make the changes to you configuration file, do a cmcheckconf and if it succeeds, do a cmapplyconf and say yes when prompted to overwrite to existing binary file.

-Ramesh

[Sanjay_6]

Hi Steve,

"cmhaltcl" will bring down the complete cluster. So at this time none of tha pckages would be working. "cmhaltcl" brings down the node only and at this time, the package running on this node can run on the adoptive node.

When you are making any of the changes to the cluster configuration parameters like hearbeat ip, timing etc, the cluster has to be down.

Hope this helps.

thanks

[Steve Bonds]

Thanks for the confirmations. Looks like I get to organize the world's nastiest maintenance window.