[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: [RFC] Support for using multiple CDs during installation



Frans Pop wrote:
> When base-config was integrated into D-I, we had find a way to make tasksel 
> install from CD images for hd-media installations. This was solved by bind 
> mounting the CD into target and telling apt-cdrom not to mount/unmount CDs.
> In the patch for apt-setup this is reverted: apt-cdrom is allowed to mount
> CDs again. Note that base-installation is not changed in any way.
> 
> For CD changing by apt-cdrom in /target to be possible, the installation CD 
> has to be unmounted in the D-I environment. While it is unmounted, no udeb
> installations are possible.
> Both in apt-setup (after scanning additional CDs) and in pkgsel (after 
> tasksel) the installation CD is mounted again so other installation steps 
> do not break.

Is the hd-media iso unmounted and then remounted somehow?

> After the change to the 2nd CD in pkgsel, the progress bar starts at 0 again
> instead of continuing from its old position.

This sounds like it's probably an apt bug.

> The prompt for CD changing works during pkgsel, but apparently not for a 
> normal apt-install. During initial tests, installation of grub failed 
> because CD2 was still mounted and I never got the prompt to change CDs.
> This is worked around by making sure CD1 is installed again, but if any 
> packages from other CDs are needed for whatever reason _after_ pkgsel, the 
> installation will hang for the same reason.
> I've not really looked yet at why this does not work.

This is at least partly because only pkgsel uses debconf-apt-progress to
proxy debconf questions and media change requests through to cdebconf.

Unfortunatly, it's not currently possible to make apt-install use
debconf-apt-progress, because it needs --from and --to to tell it
where to advance the progress bar from. I think this could be avoided,
by modifiying debconf-apt-progress to have a --no-advance option that
avoids moving the progress bar. (It could still write progress messages
to the static bar, including apt's download time estimates.)

> - if a CD change is needed to install a package _after_ pkgsel, this will
>   fail because the CD is mounted in the D-I environment (the CD drive is
>   locked)

> It would be much better if anna or udpkg could detect that the CD is not 
> mounted and ask for it to be mounted when needed and then automatically 
> unmount it again after use so not to interfere with CD changing in /target.

I don't see a way to do this that's compatible with hd-media. We could
make d-i smart enough to loop mount the hd-media iso on demand, but if
it's unmounted after use, it won't be available to apt. Unless apt
could somehow be taught to loop mount it on demand ..

-- 
see shy jo

Attachment: signature.asc
Description: Digital signature


Reply to: