F16, yum install xen, run grub2 or grubby as needed?

F16, yum install xen, run grub2 or grubby as needed?

[Konrad Rzeszutek Wilk]

Hey Michael,

I was playing today with https://admin.fedoraproject.org/updates/grubby-8.2-1.fc16?_csrf_token=014c2b18c3b6e843699e9ef1e56cf9726c5c4fc2
and https://admin.fedoraproject.org/updates/grub2-1.99-6.fc16 which make the grub.cfg have the
correct entries of Xen and Linux.

And realized that I had to manually do:

grub2-mkconfig > /boot/grub2/grub.cfg

which ends up doing the new stanza.. but in some sense I think
it makes senee for the Xen script to actually call this.

Thoughts?

Re: F16, yum install xen, run grub2 or grubby as needed?

[M A Young]

On Thu, 15 Sep 2011, Konrad Rzeszutek Wilk wrote:

> Hey Michael,
>
> I was playing today with https://admin.fedoraproject.org/updates/grubby-8.2-1.fc16?_csrf_token=014c2b18c3b6e843699e9ef1e56cf9726c5c4fc2
> and https://admin.fedoraproject.org/updates/grub2-1.99-6.fc16 which make the grub.cfg have the
> correct entries of Xen and Linux.
>
> And realized that I had to manually do:
>
> grub2-mkconfig > /boot/grub2/grub.cfg
>
> which ends up doing the new stanza.. but in some sense I think
> it makes senee for the Xen script to actually call this.
>
> Thoughts?

It probably makes sense to have a post-install/post-uninstall script in 
the xen-hypervisor RPM to run this. The updated grub2 creates a set of 
entries for each of xen-4.1.1.gz and its two symbolic links xen-4.1.gz and 
xen.gz which is a bit untidy, so perhaps it makes sense to remove the 
symbolic links.

 	Michael Young

Re: Re: F16, yum install xen, run grub2 or grubby as needed?

[Konrad Rzeszutek Wilk]

On Thu, Sep 15, 2011 at 10:29:50PM +0100, M A Young wrote:
> On Thu, 15 Sep 2011, Konrad Rzeszutek Wilk wrote:
> 
> >Hey Michael,
> >
> >I was playing today with https://admin.fedoraproject.org/updates/grubby-8.2-1.fc16?_csrf_token=014c2b18c3b6e843699e9ef1e56cf9726c5c4fc2
> >and https://admin.fedoraproject.org/updates/grub2-1.99-6.fc16 which make the grub.cfg have the
> >correct entries of Xen and Linux.
> >
> >And realized that I had to manually do:
> >
> >grub2-mkconfig > /boot/grub2/grub.cfg
> >
> >which ends up doing the new stanza.. but in some sense I think
> >it makes senee for the Xen script to actually call this.
> >
> >Thoughts?
> 
> It probably makes sense to have a post-install/post-uninstall script
> in the xen-hypervisor RPM to run this. The updated grub2 creates a
> set of entries for each of xen-4.1.1.gz and its two symbolic links
> xen-4.1.gz and xen.gz which is a bit untidy, so perhaps it makes
> sense to remove the symbolic links.


Taking this a step further.. what about re-ordering the boot order?
Say 'yum install xen-hypervisor' (which implies that the user has a good
idea of what Xen is), would make sure that the Xen 4.1.1 stanze is called
before the baremetal? Not sure what it would entail
(modifying /etc/default/grub?) and whether that is actually OK?

Re: Re: F16, yum install xen, run grub2 or grubby as needed?

[Andy Burns]

On 16 September 2011 09:35, Konrad Rzeszutek Wilk
<konrad.wilk@oracle.com> wrote:

> On Thu, Sep 15, 2011 at 10:29:50PM +0100, M A Young wrote:
>> On Thu, 15 Sep 2011, Konrad Rzeszutek Wilk wrote:
>>
>>> realized that I had to manually do:
>>> grub2-mkconfig > /boot/grub2/grub.cfg

Yes, I've been manually running that too, but the resuling grub.cfg
file from when I manually regenerate it is subtly different from the
grub.cfg generated after automatically installing a new kernel ...

The one generated by manually running grub2-mkconfig creates a Xen
submenu with all the various kernels under it, whereas after
installing a new kernel, the one generated has all the xen + kernels
in the top level menu.

>> grub2 creates a
>> set of entries for each of xen-4.1.1.gz and its two symbolic links
>> xen-4.1.gz and xen.gz which is a bit untidy, so perhaps it makes
>> sense to remove the symbolic links.

I've submitted a bug with a patch to make the /etc/20_linux_xen helper
script ignore the symbol files and symbolic links, if there's no need
for the symbolic links the patch could be even simpler.

https://bugzilla.redhat.com/show_bug.cgi?id=738085

Re: Re: F16, yum install xen, run grub2 or grubby as needed?

[Konrad Rzeszutek Wilk]

On Sun, Sep 18, 2011 at 08:53:29PM +0100, Andy Burns wrote:
> On 16 September 2011 09:35, Konrad Rzeszutek Wilk
> <konrad.wilk@oracle.com> wrote:
> 
> > On Thu, Sep 15, 2011 at 10:29:50PM +0100, M A Young wrote:
> >> On Thu, 15 Sep 2011, Konrad Rzeszutek Wilk wrote:
> >>
> >>> realized that I had to manually do:
> >>> grub2-mkconfig > /boot/grub2/grub.cfg
> 
> Yes, I've been manually running that too, but the resuling grub.cfg
> file from when I manually regenerate it is subtly different from the
> grub.cfg generated after automatically installing a new kernel ...
> 
> The one generated by manually running grub2-mkconfig creates a Xen
> submenu with all the various kernels under it, whereas after
> installing a new kernel, the one generated has all the xen + kernels
> in the top level menu.

Oh, well, that is kind of convient. So you install new kernel and viola
the new kernel boots in the hypervisor kernel?


> 
> >> grub2 creates a
> >> set of entries for each of xen-4.1.1.gz and its two symbolic links
> >> xen-4.1.gz and xen.gz which is a bit untidy, so perhaps it makes
> >> sense to remove the symbolic links.
> 
> I've submitted a bug with a patch to make the /etc/20_linux_xen helper
> script ignore the symbol files and symbolic links, if there's no need
> for the symbolic links the patch could be even simpler.

Could you also send the patch to upstream grub2? So that other
distros can benefit as well?

> 
> https://bugzilla.redhat.com/show_bug.cgi?id=738085
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

Re: Re: F16, yum install xen, run grub2 or grubby as needed?

[Andy Burns]

Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:

> Andy Burns wrote:
>
>> The one generated by manually running grub2-mkconfig creates a Xen
>> submenu with all the various kernels under it, whereas after
>> installing a new kernel, the one generated has all the xen + kernels
>> in the top level menu.
>
> Oh, well, that is kind of convient. So you install new kernel and viola
> the new kernel boots in the hypervisor kernel?

No, because the baremetal stanza for the new kernel seems to always be
before the xen stanza

>> I've submitted a bug with a patch to make the /etc/20_linux_xen helper
>> script ignore the symbol files and symbolic links, if there's no need
>> for the symbolic links the patch could be even simpler.
>
> Could you also send the patch to upstream grub2? So that other
> distros can benefit as well?

Yes, will do ...

Re: Re: F16, yum install xen, run grub2 or grubby as needed?

[Andy Burns]

On 21 September 2011 19:08, Konrad Rzeszutek Wilk
<konrad.wilk@oracle.com> wrote:

> Oh, well, that is kind of convient. So you install new kernel and viola the new kernel boots in the hypervisor kernel?

The way I achieved that, is to edit /etc/default/grub to include
GRUB_DEFAULT="Xen"

which matches the submenu created by /etc/grub.d/20_linux_xen

so the submenu is the default chosen, and the newest kernel is
automatically chosen from the top item of the submenu.

I suspect there are still flies in the ointment with that, which was
when I started to notice that installing a kernel had messed with the
/boot/grub2/grub.cfg file

If my server was in the remote data centre rather than the next room,
I wouldn't be confident about rebooting it and expecting it to run the
right combination of xen+kernel.