This template is meant to serve as a general upgrade path for any Debian release. This is my standard path and will be adjusted based on the “old” current release installed on the system and the target “new” release the server is being upgraded to.

I will normally create a complete system clone and use this template to work out the entire correct and functional path for the production system in question.

Debian Release upgrade paths:

Jessie -> Buster -> Bullseye
Stretch -> Buster -> Bullseye
Buster -> Bullseye

Ensure the maintainance window you are planning is OK with all involved.

Set maintainance window for upgrade with buffer

Verify the recoverability of system from backup image

Local terminal or SSH access

i.e.:

a. Web server delivers correctly
b. php scripts execute correctly
c. DB runs correctly
d. mail works

find NON-Pure Debian packages
  # apt install aptitude apt-forktracer
  # aptitude search '~i(!~ODebian)'
  # apt-forktracer | sort

  # aptitude
Select GO and review

check /etc/apt/preferences & /etc/apt/preferences.d/ for entries

# dpkg --audit
# aptitude search "~ahold"
# dpkg --get-selections | grep 'hold$'

To remove a hold on a package:

echo package_name install | dpkg --set-selections

# sudo apt update

# sudo apt upgrade

Verify all services required of current host is functioning correctly

# sudo apt dist-upgrade

see 3.3 above

# sudo sed -i 's/CURRENT_RELEASE/TARGET_RELEASE/g' /etc/apt/sources.list
# sudo sed -i 's/CURRENT_RELEASE/TARGET_RELEASE/g' /etc/apt/sources.list.d/*

Only required for special in-house software

Only required for special 3rd party delivered software

Ensure all partition mountpoints are mounted read-write

# mount -o remount,rw /mountpoint

# script -t 2>~/upgrade-TARGET_RELEASEstep.time -a ~/upgrade-TARGET_RELEASEstep.script

To replay session use scriptreplay

# scriptreplay ~/upgrade-TARGET_RELEASE.time ~/upgrade-TARGET_RELEASE.script

# apt-get update

# apt-get -o APT::Get::Trivial-Only=true dist-upgrade

# apt-get upgrade

See 3.3 above

# apt-get dist-upgrade

See 3.3 above

# apt-get dist-upgrade -o APT::Immediate-Configure=0

use -o APT::Force-LoopBreak=1 with apt-get or

# dpkg --remove package_name

or

# apt-get -f install
# dpkg --configure --pending

or

# dpkg --install /path/to/package_name.deb

# dpkg -r --force-depends package_name

Usually answer “YES” to files in /etc/init.d directory or /etc/manpath.config

Ctrl+Alt+F1 should recover the terminal window

Check for meta package

# dpkg -l "linux-image*" | grep ^ii | grep -i meta

if none are installed check which ones are available

# apt-cache search linux-image- | grep -i meta | grep -v transition

select correct one based on value returned by running “uname -r” eg. kernel “2.6.32-5-amd64”

# apt-cache show linux-image-amd64

Remove redundant or obsolete packages. see 5.3 above

get list of removed packages

# dpkg -l | awk '/^rc/ { print $2 }'

remove using

# apt-get purge $(dpkg -l | awk '/^rc/ { print $2 }')

or use

# aptitude search '~c'
# aptitude purge '~c'