SG Package Monitored Processes/Resources

[Michele (Mike) Alberton]

Hi Folks !

We need to show to a customer how Service Guards reacts to package failover(s).
We've tried unplugging our Lan cables and the system properly reacts moving the package to the secondary node.
Unfortunately this event does not drive the SG to mark Node Switch to disabled (on primary), so that even if the Failback policy is Manual as soon as the Lan cables are back in place I could switch the package back on primary node.
Now we want to show them that in case of a real failover, the Node switch should become disabled, so that I was thinking about killing one of the service processes to simulate a real failure. How can I check which processes are monitored by SG, in order to initiate a Failover ?

Thanks in advance !

Mike

[Stephen Doud · Accepted solution]

Hi Mike,

When a pkg is failed off of one node to another, ServiceGuard normally marks the primary node as "disabled" in the NODE-SWITCHING report of cmviewcl.

ServiceGuard monitors the SERVICE_CMD items listed in the package control script which is used to start/stop the package. Kill that command, and ServiceGuard will halt the package on that node, and if an adoptive node is 'enabled' to accept the package, will start it.

-S.

[T G Manikandan]

This link can help you

http://www1.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000062686693

[Robin Wakefield]

Hi Mike,

Check the output of "cmviewcl -v", and see which services have the "MAX_RESTARTS" column not set to unlimited.

Then look in the package control file to see what command this service is registered against. Killing this process should switch the cluster.

rgds, Robin

[Michele (Mike) Alberton]

Good !

Thank You so much !

Since you've been so kind, can I ask you why the failure of a Lan is not treated the same way (I mean the Node switch is not disabled ?)

I was thinking that if the Lan is DOWN the package won't be able anyway to start, but if the connection goes up and down (let's say because of faulty cables), this could initiate a ping pong, isn't it?

Thanks !
Mike

[Stephen Doud]

Hi Mike,

SG treats a packake subnet resource failure differently then a package service.

Let's say the entire package subnet failed on all nodes. SG would halt the pkg and await the restoration of the subnet. Whichever node normally able to operate the package registers the subnet up first will start the package. If the original primary node sees the subnet restored first, we'd want it to start the package. Hence, it's never disabled from running the package when only the subnet resource is unavailable.

-S.

[Michele (Mike) Alberton]

Thanks Stephen for the exlpanation !

Cheers,

Mike