Linux: Debian release upgrade
This article describe update from Debian 8 (Jessie) to Debian 9 (Stretch). It may be used also for future updates but keep in mind that references to "Stretch" needs to be updated for such a use case. Also take extra precaution if you use third party software. Additional compatibility checks and update steps may be necessary if third party software is installed on system.
Contents
Take system backup and offload it
Update itself should be flawless but ...
- new packages mean new version of configuration and data structures (database files). Relevant files are converted during update so everything will work fine. In case you will need (or like) to rollback update then backup will be essential for this.
- update itself is highly tested by Debian developers but it may be case that your configuration is somehow special and update fail. It is just much easier to restore system than try to repair it ...
It is good practice to backup system prior to update and offload backup data from system.
Search for obsolete packages
aptitude search '~o'
This command list all packages that are no longer present in repository. Those packages are either obsolete or manually installed. Consider removing all those packages before continuing.
Perform full Jessie Upgrade
It is essential to get system up2date on Jessie before we move to Stretch.
apt-get update apt-get upgrade apt-get dist-upgrade apt-get autoremove apt-get clean
Check package database
This step will performs database sanity and consistency check.
dpkg --audit
Correct all errors before continuing.
apt-mark showhold
If there are packages On Hold then un-hold them and upgrade before continuing. If you skip this check then you may face problems with dependencies in next steps.
Modify repository configuration
Open /etc/apt/sources.list for editing and replace references to jessie with stretch.
File should looks like this:
# stretch sources deb http://ftp.sk.debian.org/debian/ stretch main deb-src http://ftp.sk.debian.org/debian/ stretch main deb http://security.debian.org/ stretch/updates main deb-src http://security.debian.org/ stretch/updates main # stretch-updates, previously known as 'volatile' deb http://ftp.sk.debian.org/debian/ stretch-updates main deb-src http://ftp.sk.debian.org/debian/ stretch-updates main
Upgrade to Stretch
System will update itself to Stretch at this point. Key element is "Stretch" sources from previous step.
Watch closely messages generated by update. There may be additional steps needed depending on installed packages.
apt-get update apt-get upgrade apt-get dist-upgrade apt-get autoremove apt-get clean
Verify package database (yes, again)
dpkg --audit
Correct all errors before continuing.
aptitude search '~o'
This command list all packages that are no longer present in repository. Those packages are either obsolete or manually installed. Consider removing all those packages before continuing.
Reboot system
Warning: Debian Stretch adapt predictable network device names. This mean that network device names may change during reboot from "Jessie" to "Stretch". Modification of /etc/network/interfaces may be necessary.
This step is necessary to load new kernel and also good practice to see if system boot in case reboot is needed.
shutdown -r now
Final verification of debian version:
lsb_release -a
Enjoy new system
You should have working Debian Stretch installation at this point. Additional update steps will highly depend on your environment but I still have one recommendation.
Run once more "Upgrade to Stretch" to see that everything is fine after reboot. There may be packages that get released during reboot or additional candidates for cleanup after you remove obsolete packages.
