[Users] Templates and originating VM relationship

[René Koch (ovido)]

On Tue, 2013-03-26 at 15:50 +0100, Gianluca Cecchi wrote:
> On Tue, Mar 26, 2013 at 3:41 PM, René Koch (ovido)  wrote:
> 
> > Unlike Vmware (which converts a vm into a template) RHEV/oVirt is
> > copying the vm into a template.
> >
> > So you can remove or edit your original vm without having an impact on
> > your template.
> 
> OK.
> So the note in Procedure 9.1 at page 162 of RHEV 3.1 admin guide is
> not correct....

I didn't had issues when creating templates from vms without snapshots
and reusing the vm again.

I think it's because of sealing/sysprep.

Let's assume you create a template of a windows vm, I would do the
following steps:
1. Install all apps and settings in your vm
2. Take a snapshot of this vm
3. sysprep your vm
4. Create a template
5. Revert to previous snapshot when reusing your vm, as otherwise
sysprep would start (and you don't want it for your master-image).



> 
> 
> > More important is the template provisioning method when creating vms
> > from your template. If you choose Thin, only changes between your
> > template and your vm are written to your vms disk file, where clone
> > creates a clone of your template's disk. Template thin provisioning
> > saves disk space, but you can't delete the template as long as you don't
> > delete all vms linked to this template.
> 
> This was clear to me based on manual contents, but thanks for the remainder.
> 
> Gianluca