Re: [Xen-devel] Deficiencies in guest bootloader design

[Ewan Mellor <ewan@xxxxxxxxxxxxx>]

On Thu, Apr 13, 2006 at 10:24:44AM -0500, Anthony Liguori wrote:

> Ewan Mellor wrote:
> >On Thu, Apr 13, 2006 at 04:29:23PM +0200, Michael Paesold wrote:
> >
> >  
> >>I have tried to use a dynamically activated block device with pygrub 
> >>(actually drbd, but could be enbd, nbd, or simply any vbd other than phy: 
> >>or file:). That does not work.
> >>
> >>The problem is that the bootloader is not called from Xend, after virtual 
> >>block devices are setup, but instead it is called directly from xm, i.e. 
> >>in xm/create.py.
> >>
> >>If I have looked correctly, (1) a bootloader cannot be used for devices 
> >>such as nbd: or enbd: devices, and (2) a bootloader cannot be used when 
> >>accessing Xend via XML-RPC (or libvirt or similar), because the whole 
> >>notion of a "bootloader" at domain creation time is only available in 
> >>"xm", but not in Xend.
> >>
> >>It should be fixable, since at least on guest *restart*, 
> >>xend/XendDomainInfo.py already uses the bootloader to re-extract the 
> >>kernel image from the vbd.
> >>
> >>Is there anyone working on bootloader improvements? If not, is a change 
> >>to move the bootloader stuff from xm to Xend acceptable? In that case I 
> >>could try to come up with a patch.
> >>    
> >
> >Certainly such a patch would be accepted.
> >  
> 
> Just as a warning, it's not going to be simple to run something like 
> pygrub from Xend.  The reason it runs from xm now is that it needs to 
> interact with the user.  If it were launched from Xend, it need to find 
> a way to attach to a PTY that xenconsoled would use so that it can 
> display the text over the normal console before actually launching the 
> domain.
> 
> It's certainly not impossible but it touches quite a few things.

So how _is_ the virtual frame buffer coming along?  ;-)

Ewan.

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