[one-users] Upgrade 3.2 -> 3.4 with active VMs

[Carlos Martín Sánchez]

Hi Michael,

The reason why VMs have to be shut down is because the storage model has
changed quite a bit in this last version, and we couldn't come up with a
migration process that felt solid enough for any deployment.

But, since you said you are ready for lots of manual work, let's try this:

First, edit /usr/lib/one/ruby/onedb/3.3.0_to_3.3.80.rb and comment out
lines 35 to 60 [1] to disable the VM status check.
Then upgrade the opennebula DB with the onedb command [2]

Before you start opennebula again, you need to adapt the previous VM
storage directories to the new 3.4 hierarchy. Assuming you don't have
VM_DIR nor DATASTORE_LOCATION defined in oned.conf, this is how the VM
directories look in both versions:

3.2:
/var/lib/one/<vm_id>/images/disk.i
/var/lib/images/abcde

3.4:
/var/lib/one/datastores/0/<vm_id>/disk.i
/var/lib/one/datastores/1/abcde

So what you need to do in the front-end *and each host* is to individually
link each existing VM dir:

ln -s /var/lib/one/<vm_id>/images /var/lib/one/datastores/0/<vm_id>

Let me stress that this must be done in all the hosts.

Please take into account that this is just the basic idea, and that *we
haven't tested this*. You may run into problems depending on your
infrastructure configuration. For instance, if you were using the tm_shared
drivers, VMs containing persistent Images will have links like this one:

/var/lib/one/7/images/disk.1 -> /var/lib/images/qwerty

If you move the image files to their new destination in
/var/lib/one/datastores/1, like the documentation says, you will break
those VM disk links.


Another problem that may be important to you is that VMs over which you
executed saveas [3] won't be able to save the changes back to the locked
Image once the VM is shut down. In the best scenario, you will find the
files inside /var/lib/one/<vm_id>/images/, but I'm not sure about this, you
may lose your changes...
You can locate these VMs looking for VM/DISK/SAVE_AS, and the Images all
have "-" as the value of IMAGE/SOURCE.


As I said, this is not a tested or recommended procedure.


Good luck,
Carlos

[1]
http://dev.opennebula.org/projects/opennebula/repository/revisions/one-3.4/entry/src/onedb/3.3.0_to_3.3.80.rb
[2] http://opennebula.org/documentation:rel3.4:upgrade
[3]
http://opennebula.org/documentation:archives:rel3.2:img_guide#save_changes

--
Carlos Martín, MSc
Project Engineer
OpenNebula - The Open-source Solution for Data Center Virtualization
www.OpenNebula.org | cmartin at opennebula.org |
@OpenNebula<http://twitter.com/opennebula><cmartin at opennebula.org>



On Thu, Apr 12, 2012 at 2:41 PM, Michael Kutzner <michael.kutzner at virtion.de
> wrote:

> Hello,
>
> first of all congratulations to the final 3.4 and many thanx for the hard
> work!
>
> I just wanted to upgrade to 3.4 and started reading.
> I noticed reading the upgrade guide that all active VMs have to be shut
> down.
>
> Is there any chance to upgrade without powering down all VMs? Even with
> lots of
> manual work?
>
>
> Many thanx,
>  Michael
>
>
> _______________________________________________
> Users mailing list
> Users at lists.opennebula.org
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>
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