[virt-tools-list] Virt Tools Survey: What to do about virt-clone

Tue May 10 12:58:19 UTC 2011

>
> (a) Is cloning guests useful for you or not?  Often or infrequently?
>

I clone VMs once os twice a month. It's usefull for creating test
environments for the applications this company runs, and to safely backup a
VM before doing some change of update.

(b) Do you currently use virt-clone to clone guests?
>

I use virt-manager. Don't know what command virt-manager uses. I just right
click the VM and clone it.

(c) Do you have a homebrew method to clone guests?  What does it do?

I don't. If I need to clone a VM without virt-manager, I would make copies
of VM hard disk and vm XML, you know, manually copy the stuff.

(d) Do you use another tool to clone guests?  (And how is it?)

No, I don't.

(e) When you clone a guest, do you "sysprep" it or would you like to?
> (Using the term "sysprep" generically here, I mean any sort of
> reinitialization for Linux or Windows guests).
>

I don't. Just change the MAC address (specially in windows guests).

(f) How do you feel about a multi-step process?

I really would enjoy having more options when cloning machine, could save
lots of time in here. I don't resize cloned machines, for example. When I
need to change the size of the cloned machine, I just create a new one from
scratch.

(g) Have you had other problems with cloning guests?
>

If I change the Mac address of the NICs of a linux guest, O.S. can't find
the NIC anymore. It's a problem to me, since I started working with linux
servers about a year ago and I'm still (! lol) not familiar with "manually
adding hardware"...

(h) What have I missed out in this analysis?  What other features have
> you missed in virt-clone?
>

Can't remember any right now... =D

On Tue, May 10, 2011 at 8:56 AM, Richard W.M. Jones <rjones at redhat.com>wrote:

> I've volunteered for the task of fixing virt-clone[0].  There are a
> number of bugs which need to be addressed.  Unfortunately the current
> virt-clone is broken-by-design since it cannot make changes inside the
> guest.
>
>  [0] http://linux.die.net/man/1/virt-clone
>
> The bugs boil down to what Microsoft calls "sysprepping" the clone,
> which is to say, removing its existing identity, hostname, ssh host
> keys, persistent network rules, host SID and workgroup name (for
> Windows).  It's helpful for Linux guests to remove some of this
> stuff[1] -- it will make the cloning process smoother.  For Windows
> it's absolutely required[2].
>
>  [1]
> https://rwmj.wordpress.com/2010/09/24/tip-my-procedure-for-cloning-a-fedora-vm/
>  [2] http://technet.microsoft.com/en-us/library/cc721940%28WS.10%29.aspx
>
> All that virt-clone can do now is to copy the guest and make some
> simple changes to the libvirt XML (eg. giving it a new MAC address).
> It doesn't even address the sysprepping problem.
>
> The problem with sysprepping is that it's hard to do, and it's
> different for every operating system.  I've summarized some of the
> techniques below.  Worse than that, for some OSes there are different
> levels of sysprepping that an administrator might want; also see
> below.
>
> So I'd like feedback from "virt-clone next generation" users:
>
> (a) Is cloning guests useful for you or not?  Often or infrequently?
>
> (b) Do you currently use virt-clone to clone guests?
>
> (c) Do you have a homebrew method to clone guests?  What does it do?
>
> (d) Do you use another tool to clone guests?  (And how is it?)
>
> (e) When you clone a guest, do you "sysprep" it or would you like to?
> (Using the term "sysprep" generically here, I mean any sort of
> reinitialization for Linux or Windows guests).
>
> (f) How do you feel about a multi-step process?
>
>  virt-clone -> virt-sysprep -> virt-resize (for example)
>
> (g) Have you had other problems with cloning guests?
>
> (h) What have I missed out in this analysis?  What other features have
> you missed in virt-clone?
>
> Sysprepping Windows
> -------------------
>
> This is a complex, manual process.  We do some steps to automate it in
> RHEV.  It's best to read Microsoft's online documentation at
> [2][3][4].
>
>  [3] http://support.microsoft.com/kb/302577
>  [4] http://blogs.technet.com/b/megand/archive/2005/01/20/357570.aspx
>
> Fedora
> ------
>
> In theory you can just write a file /.unconfigured in the root, and
> Fedora will go through the firstboot process at next boot (it will
> reset timezone, root password, netconfig, keyboard, authentication).
>
> Some admins will *not* want all of these things to be reset, and will
> want either a lesser degree of unconfiguration, or will want to
> control each thing manually.
>
> I'm not totally convinced that this hasn't been broken by systemd
> introduction in Fedora 15.
>
> general Linux
> -------------
>
> See [1].
>
> Rich.
>
> --
> Richard Jones, Virtualization Group, Red Hat
> http://people.redhat.com/~rjones
> virt-df <http://people.redhat.com/%7Erjones%0Avirt-df> lists disk usage of
> guests without needing to install any
> software inside the virtual machine.  Supports Linux and Windows.
> http://et.redhat.com/~rjones/virt-df/
>
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>
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