Re: [gentoo-user] {OT} Allow work from home?

[J. Roeleveld]

On Tuesday, January 19, 2016 11:22:02 PM lee wrote:
> "J. Roeleveld" <joost@××××××××.org> writes:
> > [...]
> > If disk-space is considered too expensive, you could even have every VM
> > use
> > the same base image. And have them store only the differences of the disk.
> > eg:
> > 1) Create a VM
> > 2) Snapshot the disk (with the VM shutdown)
> > 3) create a new VM based on the snapshot
> >
> > Repeat 2 and 3 for as many clones you want.
> >
> > Most installs don't change that much when dealing with standardized
> > desktops.
> How does that work?  IIUC, when you created a snapshot, any changes you
> make to the snapshotted (or how that is called) file system are being
> referenced by the snapshot which you can either destroy or abandon.
> When you destroy it, the changes you made are being applied to the
> file system you snapshotted (because someone decided to use a very
> misleading terminology), and when you abandon it, the changes are thrown
> away and you end up with the file system as it was before the snapshot
> was created.
>
> In any case, you do not get multiple versions (which only reference the
> changes made) of the file system you snapshotted but only one current
> version.
>
> Do you need to use a special file system or something which provides
> this kind of multiple copies when you make snapshots?

I use LVM for this.

Steps are simple:
1) Create a LV (lv_1)
2) Create and install a VM using this LV (lv_1)
3) Stop the VM
4) Create multiple snapshots based on lv_1 (slv_1a, slv_1b, ......)
5) Create multiple VMs using the snapshots (vm1a -> slv_1a, vm1b, 
slv_1b,.....)

Start the VMs

This way you can overcommit on the actual diskspace as only changes are taking 
up diskspace.
If you force everyone on the same base-image, the differences should not be too 
large.

If you also force users to store files on a shared filesystem, it shouldn't be 
too much of a difficulty to occasionally move everyone to a new base-image when 
the updates are causing the snapshots to grow too much.

--
Joost