On Sun, 17 Jan 2016 at 13:56:24 +0100, Geert Stappers wrote:
> Still feel free to describe the use case, the (wanted) setup.
AFAICT (please correct me if I'm wrong) Stefanos wants to share a host
directory with a KVM guest only to expose the preseeding file. (The
other options being either to add said file to the ISO image, or to set
a HTTP or FTP server and serve the file there.)
But 9pvirtio can be useful beyond mere preseeding. For instance I'm
also using it to expose the directory containing my local (partial)
mirror, which enables automatic installation on networkless VMs using
file:// APT URIs. (Right now I have to modify the initramfs image to
add the relevant images and mount the 9p virtio device.)
Furthermore I can easily add local packages to the mirror, so it's
specially useful in the context of a test suite to test installation
setups (I'm doing that to check for regressions in the cryptsetup
package). Another big advantage is that it doesn't require me to
download an ISO image: it's enough to boot with the latest initramfs
image and kernel [0]. And using rsync to keep the mirror in sync is
more efficient that downloading an ISO image.
All in all, the “9p://tag/path” source URI that was proposed in Message
#22 doesn't fit my use case (unless 9p:// support is added everywhere
else in the installer), because I can't control where the device is
being mounted hence can't point file:// URIs to it. How about a new
parameter “premount=$type:$device:$mountpoint:$options”? It's a bit
more verbose but I could instantiate it with
premount=9p:d-i:/cdrom:trans=virtio,version=9p2000.L
and reuse the existing “preseed/file=/cdrom/preseed.cfg” parameter.
“preseed=9p://$mounttag/$file” could be an alias for
$mnt=$(mktemp)
premount=9p:$mounttag:$mnt:trans=virtio,version=9p2000.L
preseed/file=$mnt/preseed.cfg
--
Guilhem.
[0]
http://cdimage.debian.org/debian/dists/sid/main/installer-amd64/current/images/cdrom/initrd.gz
and
http://cdimage.debian.org/debian/dists/sid/main/installer-amd64/current/images/cdrom/vmlinuz
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