Re: pygrub/hvm boot with alternate script= for block devices

["Roger Pau Monné" <roger.pau@citrix.com>]

On 19/01/13 16:46, James Dingwall wrote:
> 
> Hi,
> 
> I am doing some experimentation with xen and Ceph and have a problem
> booting my guest when my disk = [] uses an alternate block script.
> Installation from a .iso was ok since the boot device was a file but 
> now
> trying to boot from the rbd neither the hvmbuilder or pygrub can start
> as they treat the first value after target= as the /dev node to try and
> use.

Yes, this is known problem which I'm trying to solve with this series:

http://lists.xen.org/archives/html/xen-devel/2012-12/msg01753.html

> 
> My disk parameter looks like:
> disk = [ 'format=raw, script=block-rbd, vdev=xvda, access=w,
> target=image=ubuntu-test' ]
> 
> In the pygrub log:
> OSError: [Errno 2] No such file or directory: 'image=ubuntu-test'
> 
> and there is a similar error trying an HVM boot.
> 
> My block-rbd script parses the value passed after target= to
> dynamically rbd map the image and then call the write_dev function from
> block-common.sh to save the corresponding /dev name in xenstore.
> According to the logging that I have in my block-rbd script this isn't
> even called before pygrub is executed.

The only solution right now will be to use PV guests and boot directly
with the kernel (no pygrub)

> Is there a good reason that the block devices aren't connected before
> pygrub is called so that it can then be invoked with the appropriate
> /dev device that has been written in xenstore?