-<p>For some years now, I have wondered how we should handle laptops in
-Debian Edu. The Debian Edu infrastructure is mostly designed to
-handle stationary computers, and less suited for computers that come
-and go.</p>
-
-<p>Now I finally believe I have an sensible idea on how to adjust
-Debian Edu for laptops, by introducing a new profile for them, for
-example called Roaming Workstations. Here are my thought on this.
-The setup would consist of the following:</p>
-
-<ul>
-
- <li>During installation, the user name of the owner / primary usre of
- the laptop is requested and a local home directory is set up for
- the user, with uid and gid information fetched from the LDAP
- server. This allow the user to work also when offline. The
- central home directory can be available in a subdirectory on
- request, for example mounted via CIFS. It could be mounted
- automatically when a user log in while on the Debian Edu network,
- and unmounted when the machine is taken away (network down,
- hibernate, etc), it can be set up to do automatic mounting on
- request (using autofs), or perhaps some GUI button on the desktop
- can be used to access it when needed. Perhaps it is enough to use
- the fish protocol in KDE?</li>
-
- <li>Password checking is set up to use LDAP or Kerberos
- authentication when the machine is on the Debian Edu network, and
- to cache the password for offline checking when the machine unable
- to reach the LDAP or Kerberos server. This can be done using
- <a href="http://www.padl.com/OSS/pam_ccreds.html">libpam-ccreds</a>
- or the Fedora developed
- <a href="https://fedoraproject.org/wiki/Features/SSSD">System
- Security Services Daemon</a> packages.</li>
-
- <li>File synchronisation with the central home directory is set up
- using a shared directory in both the local and the central home
- directory, using unison.</li>
-
- <li>Printing should be set up to print to all printers broadcasting
- their existence on the local network, and should then work out of
- the box with CUPS. For sites needing accurate printer quotas, some
- system with Kerberos authentication or printing via ssh could be
- implemented.</li>
-
- <li>For users that should have local root access to their laptop,
- sudo should be used to allow this to the local user.</li>
-
- <li>It would be nice if user and group information from LDAP is
- cached on the client, but given that there are entries for the
- local user and primary group in /etc/, it should not be needed.</li>
-
-</ul>
-
-<p>I believe all the pieces to implement this are in Debian/testing at
-the moment. If we work quickly, we should be able to get this ready
-in time for the Squeeze release to freeze. Some of the pieces need
-tweaking, like libpam-ccreds should get support for pam-auth-update
-(<a href="http://bugs.debian.org/566718">#566718</a>) and nslcd (or
-perhaps debian-edu-config) should get some integration code to stop
-its daemon when the LDAP server is unavailable to avoid long timeouts
-when disconnected from the net. If we get Kerberos enabled, we need
-to make sure we avoid long timeouts there too.</p>
-
-<p>If you want to help out with implementing this for Debian Edu,
-please contact us on debian-edu@lists.debian.org.</p>
+<p>The last few days I have done some upgrade testing in Debian, to
+see if the upgrade from Lenny to Squeeze will go smoothly. A few bugs
+have been discovered and reported in the process
+(<a href="http://bugs.debian.org/585410">#585410</a> in nagios3-cgi,
+<a href="http://bugs.debian.org/584879">#584879</a> already fixed in
+enscript and <a href="http://bugs.debian.org/584861">#584861</a> in
+kdebase-workspace-data), and to get a more regular testing going on, I
+am working on a script to automate the test.</p>
+
+<p>The idea is to create a Lenny chroot and use tasksel to install a
+Gnome or KDE desktop installation inside the chroot before upgrading
+it. To ensure no services are started in the chroot, a policy-rc.d
+script is inserted. To make sure tasksel believe it is to install a
+desktop on a laptop, the tasksel tests are replaced in the chroot
+(only acceptable because this is a throw-away chroot).</p>
+
+<p>A naive upgrade from Lenny to Squeeze using aptitude dist-upgrade
+currently always fail because udev refuses to upgrade with the kernel
+in Lenny, so to avoid that problem the file /etc/udev/kernel-upgrade
+is created. The bug report
+<a href="http://bugs.debian.org/566000">#566000</a> make me suspect
+this problem do not trigger in a chroot, but I touch the file anyway
+to make sure the upgrade go well. Testing on virtual and real
+hardware have failed me because of udev so far, and creating this file
+do the trick in such settings anyway. This is a
+<a href="http://www.linuxquestions.org/questions/debian-26/failed-dist-upgrade-due-to-udev-config_sysfs_deprecated-nonsense-804130/">known
+issue</a> and the current udev behaviour is intended by the udev
+maintainer because he lack the resources to rewrite udev to keep
+working with old kernels or something like that. I really wish the
+udev upstream would keep udev backwards compatible, to avoid such
+upgrade problem, but given that they fail to do so, I guess
+documenting the way out of this mess is the best option we got for
+Debian Squeeze.</p>
+
+<p>Anyway, back to the task at hand, testing upgrades. This test
+script, which I call <tt>upgrade-test</tt> for now, is doing the
+trick:</p>
+
+<blockquote><pre>
+#!/bin/sh
+set -ex
+
+if [ "$1" ] ; then
+ desktop=$1
+else
+ desktop=gnome
+fi
+
+from=lenny
+to=squeeze
+
+exec < /dev/null
+unset LANG
+mirror=http://ftp.skolelinux.org/debian
+tmpdir=chroot-$from-upgrade-$to-$desktop
+fuser -mv .
+debootstrap $from $tmpdir $mirror
+chroot $tmpdir aptitude update
+cat > $tmpdir/usr/sbin/policy-rc.d <<EOF
+#!/bin/sh
+exit 101
+EOF
+chmod a+rx $tmpdir/usr/sbin/policy-rc.d
+exit_cleanup() {
+ umount $tmpdir/proc
+}
+mount -t proc proc $tmpdir/proc
+# Make sure proc is unmounted also on failure
+trap exit_cleanup EXIT INT
+
+chroot $tmpdir aptitude -y install debconf-utils
+
+# Make sure tasksel autoselection trigger. It need the test scripts
+# to return the correct answers.
+echo tasksel tasksel/desktop multiselect $desktop | \
+ chroot $tmpdir debconf-set-selections
+
+# Include the desktop and laptop task
+for test in desktop laptop ; do
+ echo > $tmpdir/usr/lib/tasksel/tests/$test <<EOF
+#!/bin/sh
+exit 2
+EOF
+ chmod a+rx $tmpdir/usr/lib/tasksel/tests/$test
+done
+
+DEBIAN_FRONTEND=noninteractive
+DEBIAN_PRIORITY=critical
+export DEBIAN_FRONTEND DEBIAN_PRIORITY
+chroot $tmpdir tasksel --new-install
+
+echo deb $mirror $to main > $tmpdir/etc/apt/sources.list
+chroot $tmpdir aptitude update
+touch $tmpdir/etc/udev/kernel-upgrade
+chroot $tmpdir aptitude -y dist-upgrade
+fuser -mv
+</pre></blockquote>
+
+<p>I suspect it would be useful to test upgrades with both apt-get and
+with aptitude, but I have not had time to look at how they behave
+differently so far. I hope to get a cron job running to do the test
+regularly and post the result on the web. The Gnome upgrade currently
+work, while the KDE upgrade fail because of the bug in
+kdebase-workspace-data</p>
+
+<p>I am not quite sure what kind of extract from the huge upgrade logs
+(KDE 167 KiB, Gnome 516 KiB) it make sense to include in this blog
+post, so I will refrain from trying. I can report that for Gnome,
+aptitude report 760 packages upgraded, 448 newly installed, 129 to
+remove and 1 not upgraded and 1024MB need to be downloaded while for
+KDE the same numbers are 702 packages upgraded, 507 newly installed,
+193 to remove and 0 not upgraded and 1117MB need to be downloaded</p>
+
+<p>I am very happy to notice that the Gnome desktop + laptop upgrade
+is able to migrate to dependency based boot sequencing and parallel
+booting without a hitch. Was unsure if there were still bugs with
+packages failing to clean up their obsolete init.d script during
+upgrades, and no such problem seem to affect the Gnome desktop+laptop
+packages.</p>
projects / homepage.git / blobdiff