[Fedora-xen] Upgrade FC5 Xen -> FC6

[Tony Coffman]

Kanwar Ranbir Sandhu wrote:
> If you don't have anything running in dom0, shouldn't it be fairly
> straight forward?  Assuming that you're using LVM for your domU(s):
>
> 1. Backup domU(s)
> 2. Backup domO
> 3. Install FC6 (leave domU(s) alone)
> 4. Boo with xen kernel
> 5. Edit domU configs so that "kernel" and "ramdisk" point to the new
> kernel.
> 6. Boot domU(s)
>
> My domO used to be a RHEL 4 box running the xen packages from xensource.
> I converted it to a FC5 box earlier this year.  It was painless.  The
> domUs came up right away.
>
> Of course, my setup is fairly simple.  Right now, I have three domUs,
> and one bridge.
>
> I'd be interested in hearing exactly what problems you had when you made
> the switch from FC4 to FC5.
>
> Regards,
>
> Ranbir
>   
Thanks for your response.  I suppose I'm little bit of a neatnik.  I 
like to have my domU kernels installed into both the dom0 and into the 
domU.  I install them into the domU so that I don't have to manually 
copy modules into the domU everytime I make a kernel change.

With your process above how do you handle the absence of the xennet 
kernel module in your domU's?  Or did you just upgrade the domU's at the 
same time?

I do use LVM for guests and there is nothing running in dom0.

Since FC6 DomU kernel won't run on FC5 dom0 I'm thinking about one of 
these approaches

Approach A - Upgrade domU's first, then upgrade dom0
1.  Upgrade domU's to FC6 over time but continue to run an FC5 domU 
kernel.  This requires that I uninstall HAL in the domU's due to an RPM 
dependancy requirement but that works for my purposes (simple servers).
2.  Upgrade the dom0 to FC6 and then switch my Fedora domU's to run the 
FC6 domU kernel

Approach B - Upgrade the dom0 first then upgrade the domU's
1.  Upgrade (or perform a parallel fresh install) of the dom0 with FC6.
2.  Run the FC6 domU kernel in all domU's.  This will probably involved 
copying some kernel modules manually into the filesystem for each domU 
(xennet and maybe the framebuffer console modules?  I haven't tried this 
yet so I'm not sure.)
3.  Upgrade the domU's over time to FC6.

This whole approach only really deals with Fedora domU's.  I have a few 
others guests that I boot occasionally that I leave out of this 
discussion to keep it focused on the Fedora issues involved.

For the FC4 -> FC5 transition I used approach B with great success.  I 
used that because I needed time to get the domU's migrated on a 
scheduled basis.  It'll be interesting to see if there are any 
additional issues.

I'm looking forward to XEN ABI and API stability in the future as it 
should really make some of these issues easier to deal with.

Regards,
--Tony Coffman