Update existing templates and populate changes to already deployed VMs.

Latest response

In one of our support cases about updating en deploying templates, the answer of RH support containted this section:

 

"There is an enhancement already filed to make it possible to modify an existing template and populate changes to already deployed vms. Future version of RHEV may include this feature."

 

With that a BUG# (unfortunatly not accessible to me): https://bugzilla.redhat.com/show_bug.cgi?id=558995

 

Does anybody have any information about this (any non-private source, maybe some work on oVirt?). I'm really curious how it would work to update templates/vms this way.

 

Thnx!

Responses

Looks like it's taking a while to get an answer from the community here, so I've reached out to some Red Hat folks who might able to help answer this.

RHEV 3.1 will not include this feature. There are some partner solutions that might be able to provide this functionality, so keep an eye on marketplace.redhat.com

I got a reply from RH Support:

 

This is a feature request submitted to Product Management to consider for the future RHEV road map. It has not yet been implemented in oVirt.

Technical Details:

Provide a mechanism to modify a template and have the guests started from that template recognize the changes at the next reboot. This will make system updates, patch deployment,
deployment of applications in batch very easier for the admin. 

Use Case:

"I create a VM at time t, from it I create a template. Out of this template, I create 200 VMs and provide it to my users.

At t+1, I have got a patch + new applications to provide to my user. I would like to do a copy of my original template, start it and modify it. In an ideal world, I would like to say that at the next reboot of the VMs or at 5:00 AM, it should switch from the old template to my new template. I should not require to rebuild a new pool out of this new
template."

Hi Vincent,

 

Thanks for coming back to share the solution with the community! Next time, though, I'd encourage you to post in your own words rather than copy/pasting from a case email. :)

I'd find this incredibly useful as a feature too.      How can I and some weight to this RFE to ensure it get the focus it deserves ?

Raise a support case making reference to the BZ or will that get ignored as a dup ?

 

Cheers

if you raise a case asking for the same thing, it will be attached to this BZ, making it weigh more than it used to with a case from a single customer. It's a bit like voting, without the extra democracy bits :)

Vincent,
For what it's worth--I think the use case mentioned above is a good case for Puppet. We lay down a very small template ("Golden image"), and then deploy Puppet on top of each host to handle our configuration management, additional packages and generic changes.
http://projects.puppetlabs.com/projects/1/wiki/downloading_puppet