Re: [RFC] Support for using multiple CDs during installation
Op 25-10-2007 om 15:52 schreef Frans Pop:
> Attached patches to apt-setup and pkgsel make it possible to scan multiple
> CD/DVDs from a set during apt-setup and use them during pkgsel.
>
> The patches have been tested and work. I've done several successful desktop
> installations using CD1 plus CD2.
> However, the patches are still a bit rough and there are some issues that
> need discussion.
>
> The main issue with the current patches is the new dialogs. Comments on them
> and suggestions for improvement are welcome.
>
> If those are fixed, the patches could be considered for inclusion even
> though there are some remaining issues (see below). I'm unsure myself
> whether any of these issues is serious enough to prevent inclusion.
>
> Changes by the patch
> --------------------
> Scanning for extra CDs is only supported:
> - if the installation CD is a full CD or DVD
> - if the installation method is not hd-media
>
> The apt-setup generator 50cdrom has been moved to 40cdrom; a new generator
> 41cdset was added to allow scanning of additional CDs. The generator for
> mirror sources run after that.
>
> 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.
>
> Remaining issues
> ----------------
> After the change to the 2nd CD in pkgsel, the progress bar starts at 0 again
> instead of continuing from its old position.
>
> 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.
>
> The mechanism to mount the CD again for the D-I environment is somewhat
> fragile, for two reasons:
> - installation of extra udebs is now not possible during pkgsel; this is
> not a serious limitation as in practice this is probably not needed
> - 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.
>
> During my tests, the first mount of a CD after changing it would
> consistently fail. This is probably a bug in VirtualBox.
> I've added a workaround for this to make working on this a bit easier, but
> that should probably be removed.
>
> Cheers,
> FJP
I miss the "why". Right now I have the unplesant feeling it is "apt-cdrom
add" re-invented. Someone willing to enlighten me?
Cheers
Geert Stappers
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