[Pkg-xen-devel] Re: [Pkg-xen-changes] r55 - trunk/debian [u]

[Ralph Passgang]

Am Samstag, 25. Februar 2006 08:17 schrieb Guido Trotter:
> On Sat, Feb 25, 2006 at 12:20:31AM +0100, Ralph Passgang wrote:
>
> Hi,
>
> > At least that was the situation I had with my packages as I tried the
> > upgrade on a production system. it was because some libs have moved from
> > one binary package to another and dpkg refuses to overwrite files that
> > are still installed within another package. I guess that problem still
> > exists.
>
> Then we need for the new package to have a "Replaces:" on the first one...

yes, probablly that fixes that, but I cannot test an upgrade anymore. I don't 
have xen2 machines anymore...

> > upgrading when running a non-xen kernel with no vm's running should be
> > fine (besides the issue mentioned already), but if you try it within a
> > xen2 kernel/hypervisor the new xen3 userspace utils will most likely not
> > be able to communicate with the hypervisor anymore, so you cannot use
> > "xm"-tools to safely shutdown vm's anymore.
>
> It seems to me that upon upgrade xendomains is called with "stop" which
> means the machines will be safely shut down (this happens in the older
> xen's prerm script)... Then they probably won't be able to restart before a
> reboot... Should we perhaps add some more checks to our xend/xendomains
> script and make it check the hypervisor/kernel version somehow before
> starting? The reboot is needed anyway, so...

If I am not totally wrong adams packages call "xend stop" and then "xendomains 
stop". By doing this the domUs will NOT be stopped, because xend was stopped 
first and xendomains will fail because it cannot contact xend anymore.

This probably means that after a upgrade from 2.0.6 -> our 3.0.1 packages 
there will still some domUs running, but the user cannot shut the domus down 
anymore (unless he is not ssh'ing into every domU). the userspace tools will 
not be able to communicate with a 2.x hypervisor.

> We could also do other things to ease upgrade! (like permit parallel
> installation of the old and the new hypervisor, or save the older utilities
> somewhere) But they seem an overkill to me, and risk creating more bugs
> than solving them! And people will probably imagine (and if they don't we
> can tell them in the usual NEWS file that they cannot upgrade lightly
> hoping all their vm won't be touched at all!)

absolutly an overkill. How do you want to keep old files, even if the xen 
packages gets updated?

Maybe we should just include a BIG warning before upgrading that it's better 
not to try a upgrade within a running xen system at all. It's the best to 
start a normal kernel (and having no domUs running then) and update xen and 
reboot the new hypervisor + kernel then.

updating when xen2 is running is not wise at all.

> > besides that, I tested the package based on the latest testing.hg + our
> > svn debian files and it worked flawlessly for me.
>
> Great!
>
> > I agree to release the package as soon as the "upgrading" problem is
> > tested and if needed fixed.
>
> Ok,
>
> Guido
>
>
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