Patching VI3 clusters

[mrstorey]

Can anybody share their best practices for patching ESX 3.0.1 clusters?

All of our ESX hosts are in HA / DRS clusters, and I've suggested that it's a good idea to make sure that all hosts in each cluster are running the same patch level. But this however, has raised a question of how we could go about verifying patches without affecting all hosts. I.e, if there was an issue with any patch, we affect every host in the cluster.

I can only think to remove one of the hosts from the cluster as a 'test host', apply patches to that, migrate some running VM's to it and then monitor for a set period, before applying the same patch level to the clustered hosts once we're happy with it.

Is this approach too paranoid? Is it quite safe to run different patch levels across hosts in a VI3 cluster?

Interested to hear your strategies and experiences!

Thanks

[cheeko · Accepted solution]

It surely simplifies the troubleshooting when the involved hosts are on the same patch level. As for your "test host": Even if the patches seem to be stable and reliable (not had any issues with applied patches so far), it's recommended to follow a process to approve the patches for your specific setup before applying them on productive hosts.

It also depends on the patch itself. Some patches don't digg that deep into your system (read the release notes) and do fix minor issues, so they can be applied without extensive testing in my opinion.

But I'm an optimist so don't nail me on this one ...

cheeko

[mrstorey]

I agree - I've never had an issue with a host as a result of applying an ESX 3.0.1 patch, it's just we're trying to draw a formal procedure of how we should go about patching now that we're all VI3 everywhere.

Most sites here don't have any non-production ESX hosts, so I guess I'll suggest demoting two of the production hosts into a 'TEST/DEV' cluster for patch testing etc.

We'll lose a bit of power from the main cluster, but at least they'll be a test area for peace-of-mind.

Thanks for your help