/!\ Before reading this upgrade guide, please note that live updates to your production servers are carried out at your own risk. Debian Edu/Skolelinux comes with ABSOLUTELY NO WARRANTY, to the extent permitted by applicable law.

Please read this chapter and the New features in Stretch chapter of this manual completely before attempting to upgrade.

General notes on upgrading

Upgrading Debian from one distribution to the next is generally rather easy. For Debian Edu this is unfortunately not yet true as we modify configuration files in ways we shouldn't. (See Debian bug 311188 for more information.) Upgrading is still possible but may require some work.

In general, upgrading the servers is more difficult than the workstations and the main-server is the most difficult to upgrade. The diskless machines are easy, as their chroot environment can be deleted and recreated, if you haven't modified it. If you have, the chroot is basically a workstation chroot anyway, so rather easy to upgrade.

If you want to be sure that after the upgrade everything works as before, you should test the upgrade on a test system or systems configured the same way as your production machines. There you can test the upgrade without risk and see if everything works as it should.

Make sure to also read the information about the current Debian Stable release in its installation manual.

It may also be wise to wait a bit and keep running Oldstable for a few weeks longer, so that others can test the upgrade and document any problems they experience. The Oldstable release of Debian Edu will receive continued support for some time after the next Stable release, but when Debian ceases support for Oldstable, Debian Edu will necessarily do the same.

Upgrades from Debian Edu Jessie

/!\ Be prepared: make sure you have tested the upgrade from Jessie in a test environment or have backups ready to be able to go back.

Please note that the following recipe applies to a default Debian Edu main server installation (desktop=kde, profiles Main Server, Workstation, LTSP Server). (For a general overview concerning jessie to stretch upgrade, see: https://www.debian.org/releases/stretch/releasenotes)

Don't use X, use a virtual console, log in as root.

Please note one difference between apt and apt-get in Stretch: By default apt-get keeps downloaded packages, apt removes them from the cache (after successful installation).

If apt finishes with an error, try to fix it and/or run apt -f install and then apt -y full-upgrade once again.

Upgrading the main server

apt update
apt full-upgrade

apt-get clean

# First, adjust for a changed profile name:
sed -i 's/Thin-Client-Server/LTSP-Server/' /etc/debian-edu/config
# Then it's best to use the new default mirror:
sed -i 's/http.debian.net/deb.debian.org/g' /etc/apt/sources.list
# Finally, replace jessie with stretch.
sed -i 's/jessie/stretch/g' /etc/apt/sources.list
apt update
apt full-upgrade

service squid stop          # This usually takes some time!
rm -rf /var/spool/squid
umount /var/spool/squid3
sed -i 's#spool/squid3#spool/squid#' /etc/fstab
mv /var/spool/squid3 /var/spool/squid
mount -a
rm /etc/squid3 -rf
rm /etc/default/squid3 -rf

ldapvi -ZD '(cn=admin)'
(Enter root password.)
Search for 'sudoHost :tjener', replace 'tjener' with 'tjener.intern'
(Enter 'y' to modify the LDAP data base.)

service autofs stop
cfengine-debian-edu -D installation
rm /etc/apache2/conf-enabled/nagios3.conf
a2dismod userdir
ln -s /etc/apache2/mods-available/userdir.load /etc/apache2/mods-available/debian-edu-userdir.load
a2enmod debian-edu-userdir
sed -i 's/udp4/udp/' /etc/inetd.conf   # Debian Bug #789667 (atftpd)
service squid start
service apache2 restart

apt update
apt install education-networked-common
apt install education-ltsp-server      # Only if profile 'LTSP-Server' is installed.

apt install debian-edu-artwork-softwaves

apt purge linux-image-3.16.0-4-amd64 
apt purge debian-edu-artwork-lines     # Only if not wanted as an alternative theme.
dpkg -P php5-imagick                   # Package might not be installed in all cases.
rm -rf /etc/php5

a2enmod php7.0                            
service apache2 restart

Reboot; log in as first user and test

Upgrading a workstation

Do all the basic things like on the main-server and without doing the things not needed. And then do this in addition.

rm /etc/ldap/ssl/ldap-server-pubkey.pem
service nslcd stop
service fetch-ldap-cert restart
service nslcd start

Upgrading LTSP chroots (default arch i386)

Make sure you have enough disk space. LTSP now uses Network Block Device (NBD). The NBD image file size is about 4 GiB (default installation). If the image is updated, another 4 GiB for a temporary file are needed.

ltsp-chroot -m -a i386 apt update
ltsp-chroot -m -a i386 apt -y full-upgrade
sed -i 's/jessie/stretch/g' /opt/ltsp/i386/etc/apt/sources.list
ltsp-chroot -m -a i386 apt update
ltsp-chroot -m -a i386 apt -y full-upgrade
ltsp-chroot -m -a i386 apt -f install
ltsp-chroot -m -a i386 apt -y full-upgrade

ltsp-chroot -m -a i386 apt --purge autoremove


To save disk space, ltsp-update-image -n could be used instead; see man ltsp-update-image.

Recreating an LTSP chroot

On the LTSP server(s) the LTSP chroot could also be recreated. The new chroot will still support both thin-clients and diskless workstations.

Remove /opt/ltsp/i386 (or /opt/ltsp/amd64, depending on your setup). If you have enough diskspace, consider backing it up.

Recreate the chroot by running debian-edu-ltsp --arch i386 (or debian-edu-ltsp --arch amd64) as root.

Upgrades from older Debian Edu / Skolelinux installations (before Jessie)

To upgrade from any older release, you will need to upgrade to the Jessie based Debian Edu release first, before you can follow the instructions provided above. Instructions are given in the Manual for Debian Edu Jessie about how to upgrade to Jessie from the previous release, Wheezy. Likewise the Wheezy manual describes how to upgrade from Squeeze.