Hi Rich,
Sorry if my mail annoys you.
Actually I have tested the QEMU KVM snapshot features with multiple overlays and found it to be working fine.
Let’s say for an example, I have installed
Windows XP as a QEMU virtual machine (The name of the VM is ‘winxp’). Then I
created two separate overlays on top of ‘winxp’ as ‘winxp-vm01’ and ‘winxp-vm02’ and
renamed the overlay images accordingly on the OS level.
Then I created another overlay on top of
‘winxp-vm01’ as ‘winscp’, boot the overlay image ‘winscp’ and installed WinSCP
on it. Third step what I did was create another
overlay file on top of ‘winscp’ as ‘7zip’ and installed 7ZIP on top of it.
The current scenario is like the following :-
/winxp-vm01 ---------> winscp ----------> 7zip ------- User1
/
/
winxp vm
\
\
\winxp-vm02 ---------- User2
So if User1 starts the 7zip overlay image using qemu-kvm, he'll be able to see WinSCP and 7ZIP installed and the VM name as 'winxp-vm01'.
So the question is is there any way we can move or copy the two overlays on top of 'winxp-vm02' so that the scenario look like the following:-
/winxp-vm01 --------- User1
/
/
winxp vm
\
\
\winxp-vm02 ---------->winscp -----------> 7zip ------- User2
So if User2 starts the 7zip overlay image using qemu-kvm, he'll be able
to see WinSCP and 7ZIP installed and the VM name as 'winxp-vm02'.
I tried with 'qemu-img rebase' option to simulate the above scenario, but unable to do that.
If this QEMU feature along with 'Libguestfs(which can be utilized to change parameters inside Windows VMs) integrates with oVirt/RHEV , then we can have a good solutions for VDI scneario.
Again sincere apologies from my side, my intention was not to know the internals of any proprietary software, but as a follower of QEMU KVM I was just curious to know if application layering can be done with QEMU.
Please put your valued input into this.
Thanks
Kausik