How to decouple an instance from a template?

[jl0815]

We want to run a large number of Windows VMs in CloudStack and would like to build monthly updated images using Packer.
These images will then replace the existing templates in ACS.

Is there a way to decouple the running VM instances from the template they were created from?
The VMs should have their own lifecycle, independent of the templates' lifecycle.

Regards,
JL

[jl0815]

Okay, I can delete the template using “force delete,” and that doesn't seem to be a problem for the running instances.
The name of the original template still appears in the overview of both the instance and the ROOT volume.
Could this cause problems later on if new templates with the same name are registered?

JL

[daviftorres]

Dear @jl0815 ,

I don't see any future issues if CloudStack (ACS) keeps a reference showing which templates the running VMs came from.

My past concern was simply that ACS defaults to linked volumes between instances and their templates. It uses a backing chain, meaning the VM disk relies on the original template.

If this link is a concern for you, there are a few ways to fix it. You can manually flatten the volumes using the CLI, or you can perform a backup and restore (the restored VM will be completely independent).

Hope this makes sense. Regards,