runbook - ubuntu dist-upgrade

upgrading ubuntu and managing configuration file changes, you might also want to use tools such as etckeeper

upgrade using do-release-upgrade

DEBIAN_FRONTEND=noninteractive do-release-upgrade --frontend=DistUpgradeViewNonInteractive

for a truly silent or unattended upgrade, you need to configure dpkg to handle changes in configuration files between versions:

sh -c 'cat > /etc/apt/apt.conf.d/90force-conf <<EOF
Dpkg::Options {
    "--force-confdef";
    "--force-confold";
}
EOF'

explanation from the dpkg man page:

confold: If a conffile has been modified and the version in the package did change, always keep the old version without prompting, unless the –force-confdef is also specified, in which case the default action is preferred.

confdef: If a conffile has been modified and the version in the package did change, always choose the default action without prompting. If there is no default action it will stop to ask the user unless –force-confnew or –force-confold is also been given, in which case it will use that to decide the final action.

post-upgrade: manage configuration file changes

locate all changed configuration files

• for .dpkg-* files:

find /etc -name "*.dpkg-*"

• for .ucf-dist files:

find /etc -name "*.ucf-dist"

• for .distUpgrade files:

find /etc -name "*.distUpgrade*"

compare and merge changes

• use vimdiff or a similar tool to compare the original file with the new version:

vimdiff /path/to/config.file /path/to/config.file.dpkg-dist
vimdiff /path/to/config.file /path/to/config.file.ucf-dist

remove temporary files

• once resolved, delete .dpkg-* and .ucf-dist files:

rm /path/to/config.file.dpkg-dist
rm /path/to/config.file.ucf-dist