See https://bugs.launchpad.net/bugs/1895302

On Tue, Sep 22, 2020, 07:41 Oliver Grawert <email address hidden>
wrote:

> please note that the stable UbuntuCore18 images regressed due to this:
>
> https://github.com/snapcore/core18/issues/170
>
> ** Bug watch added: github.com/snapcore/core18/issues #170
>    https://github.com/snapcore/core18/issues/170
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1888575
>
> Title:
>   Split motd-news config into a new package
>
> Status in base-files package in Ubuntu:
>   Fix Released
> Status in livecd-rootfs package in Ubuntu:
>   Invalid
> Status in ubuntu-meta package in Ubuntu:
>   Fix Released
> Status in base-files source package in Xenial:
>   Fix Released
> Status in livecd-rootfs source package in Xenial:
>   Triaged
> Status in ubuntu-meta source package in Xenial:
>   Fix Committed
> Status in base-files source package in Bionic:
>   Fix Released
> Status in livecd-rootfs source package in Bionic:
>   Invalid
> Status in ubuntu-meta source package in Bionic:
>   Fix Released
> Status in base-files source package in Focal:
>   Fix Released
> Status in livecd-rootfs source package in Focal:
>   Invalid
> Status in ubuntu-meta source package in Focal:
>   Fix Released
> Status in base-files source package in Groovy:
>   Fix Released
> Status in livecd-rootfs source package in Groovy:
>   Invalid
> Status in ubuntu-meta source package in Groovy:
>   Fix Released
>
> Bug description:
>   [Impact]
>   The motd-news script is largely useless for desktop users, as they
> rarely login via a text console. It makes more sense for server users.
>
>   We can use package dependencies to have the motd-news script enabled on
> servers, but disabled on desktops, and still handle upgrades. This is the
> plan:
>   - move /etc/default/motd-news from base-files into a new binary package
> (motd-news-config, produced by src:base-files)
>   - have ubuntu-server depend on motd-news-config
>   - have base-files break current ubuntu-server, so that if base-files if
> upgraded and ubuntu-server is installed, ubuntu-server will also be
> upgraded to the new version which has the depends on motd-news-config
>
>   Care must be taken to preserve a changed /etc/default/motd-news when
>   the upgrade installs the new motd-news-config package. For example, on
>   a server that has set ENABLED=0 in /etc/default/motd-news and upgrades
>   to the new base-files and ubuntu-server, and gets the new motd-config-
>   news package, ENABLED=0 must remain set.
>
>   [Test Case]
>   a) base-files installed, ubuntu-server installed, unmodified
> /e/d/motd-news
>   apt install base-files
>   - upgrades ubuntu-server
>   - installs motd-news-config
>   - /e/d/motd-news remains, motd-news remains enabled
>
>   b) base-files installed, ubuntu-server installed, modified /e/d/motd-news
>   apt install base-files
>   - upgrades ubuntu-server
>   - installs motd-news-config
>   - /e/d/motd-news remains with the original modification
>
>   c) base-files installed, ubuntu-server not installed, unmodified
> /e/d/motd-news
>   apt install base-files
>   - upgrades base-files
>   - removes /e/d/motd-news
>   - motd-news is disabled
>
>   d) base-files installed, ubuntu-server not installed, modified
> /e/d/motd-news
>   apt install base-files
>   - upgrades base-files
>   - /e/d/motd-news gets renamed to backup
>   - motd-news is disabled
>
>   e) removing motd-news-config will also remove ubuntu-server (since
>   it's a depends, and not a recommends)
>
>   f) upgrading just ubuntu-server should pull motd-news-config in, and
>   force-upgrade base-files
>
>   g) Removing motd-news-server leaves /e/d/motd-news around; purging
>   motd-news-server removes the /e/d/motd-news config file
>
>   h) base-files installed, ubuntu-server installed, removed /e/d/motd-news
>   - apt install base-files
>   - upgrades base-files, upgrades ubuntu-server, installs motd-news-config
>   - /e/d/motd-news is installed with ENABLED=0
>
>   i) base-files installed, ubuntu-server NOT installed, removed
> e/d/motd-news
>   - apt install base-files
>   - base-files is upgraded
>   - no /e/d/motd-news is installed, motd-news remains disabled
>
>   j) Perform a release upgrade from the previous ubuntu release to the
>   one being tested while having ubuntu-server NOT installed (or use a
>   desktop install). At the end, motd-news should be disabled. Verify
>   with:
>
>   $ sudo /etc/update-motd.d/50-motd-news --force
>   $ (no output)
>
>   k) Test that supporting changes for xenial are in place:
>
>     i) verify grub-legacy-ec2 is not in the xenial server seed
>     ii) verify that the rootfs manifest built from the ubuntu-cpc project
> contains the ubuntu-server package
>     iii) verify that images built from the ubuntu-cpc project which purge
> grub-legacy-ec2 have retained ubuntu-server
>
>   [Regression Potential]
>   This update is about config file ownership transfer: /e/d/motd-news
> belonged to base-files, now it belongs to motd-news-config. We tried to
> handle two important cases here:
>   a) /e/d/motd-news config was changed while it belonged to base-files.
> For example, an user could have set ENABLED=0. We need to transfer that
> change to the motd-news-config package when it is installed, otherwise this
> SRU would jsut re-enabled motd-news. This is handled in
> d/motd-news-config.postinst's configure case.
>
>   b) /e/d/motd-news config file was *removed* while it belonged to
> base-files. In such a case, a normal upgrade of the package (base-files in
> this example) would not reinstate the file. Much less this upgrade here,
> which has an explicit rm_conffile maintscript-helper for it. But the
> motd-news-config package that could be installed in the transaction would
> place the default config file back, and the default is ENABLED=1. Thus, a
> system that had motd-news disabled via removing the config file would now
> have it re-enabled after the upgrade.
>   This was trickier to handle, and we do it in base-files's postinst and
> motd-news-config's  postinst. The drawback is that in one scenario, where
> just base-files is upgraded and /e/d/motd-news was manually removed by the
> user, there will be a /e/d/motd-news.wasremoved leftover empty file (see
> "other info" below for details).
>
>   In general, the regression risks here are:
>   - have motd-news enabled again on a system where it was previously
> disabled. We tried to envision two ways it would have been disabled (set
> ENABLED=0, and remove the config file). There are probably others
>   - differences in dpkg and/or debhelper behavior in older ubuntu releases
> leading to unexpected results (should be covered by the test cases from
> this SRU)
>   - xenial in particular is trickier, because src:base-files there does
> NOT use debhelper, so many of the things we take for granted have to be
> done by hand
>   - have some sort of dpkg postinst or dependency error because of
> unpredicted scenarios. Certain assumptions are being made, like the renames
> that dpkg-maintscript-helper does, and that the filename
> /etc/default/motd-news.wasremoved that I'm touching and verifying is really
> mine and not something that was there already.
>   - the versions I'm breaking/replacing on, and using rm_conffiles on,
> must be exact. These are the versions today in the archive (2020-08-12):
>
>   base-files:
>   x: 9.4ubuntu4.12
>   b: 10.1ubuntu2.9
>   f: 11ubuntu5.1
>   g: 11ubuntu12 (was 11ubuntu10)
>
>   ubuntu-meta:
>   x: 1.361.4
>   b: 1.417.4
>   f: 1.450.1
>   g: 1.452
>
>   Which reflect in these relationships in the updated packages:
>   Groovy:
>   ubuntu-server 1.453:
>     Depends: motd-news-config
>   base-files 11ubuntu11:
>     Breaks: ubuntu-server (<< 1.453)
>     rm_conffile /etc/default/motd-news 11ubuntu11~ base-files
>   motd-news-config 11ubuntu11:
>     Breaks/Replaces: base-files (<< 11ubuntu11)
>
>   Focal:
>   ubuntu-server 1.450.2:
>     Depends: motd-news-config
>   base-files 11ubuntu5.2:
>     Breaks: ubuntu-server (<< 1.450.2)
>     rm_conffile /etc/default/motd-news 11ubuntu5.2~ base-files
>   motd-news-config 11ubuntu5.2:
>     Breaks/Replaces: base-files (<< 11ubuntu5.2)
>
>   Bionic:
>   ubuntu-server 1.417.5:
>     Depends: motd-news-config
>   base-files 10.1ubuntu2.10:
>     Breaks: ubuntu-server (<< 1.417.5)
>     rm_conffile /etc/default/motd-news 10.1ubuntu2.10~ base-files
>   motd-news-config 10.1ubuntu2.10:
>     Breaks/Replaces: base-files (<< 10.1ubuntu2.10)
>
>   Xenial:
>   ubuntu-server 1.361.5:
>     Depends: motd-news-config
>   base-files 9.4ubuntu4.13:
>     Breaks: ubuntu-server (<< 1.361.5)
>     rm_conffile /etc/default/motd-news 9.4ubuntu4.13~ base-files
>   motd-news-config 9.4ubuntu4.13:
>     Breaks/Replaces: base-files (<< 9.4ubuntu4.13)
>
>   [Other Info]
>   a) Testcase (i) will leave around an empty
> /etc/default/motd-news.wasremoved file, created by the base-files postinst.
> This file is removed by the motd-news-config postinst, but since that
> package doesn't get installed in that particular scenario, the file
> remains. I toyed with the idea of adding an extra check to base-file's
> postinst, like this:
>   --- a/debian/postinst.in
>   +++ b/debian/postinst.in
>   @@ -133,7 +133,11 @@ motd_news_config="/etc/default/motd-news"
>    if [ ! -e ${motd_news_config} ]; then
>      if [ ! -e ${motd_news_config}.dpkg-remove ]; then
>        if [ ! -e ${motd_news_config}.dpkg-backup ]; then
>   -      touch ${motd_news_config}.wasremoved
>   +      # The .wasremoved file only matters if ubuntu-server is installed,
>   +      # because that's what will pull in motd-news-config
>   +      if dpkg -l ubuntu-server 2>/dev/null | grep -q ^i; then
>   +        touch ${motd_news_config}.wasremoved
>   +      fi
>        fi
>      fi
>    fi
>
>   But deemed it too risky, and not worth further potential regressions.
>   It seemed to work, though, at least for groovy.
>
>   b) Currently the xenial cloud images, with the exception of the AWS
>   one, do not have ubuntu-server installed. This means that this SRU
>   will disable motd-news on them, unless ubuntu-server was manually
>   installed for some reason. This includes LXD xenial images as well.
>
>   c) The new motd-news-config package has its d/control priority set to
>   "optional", so a release upgrade won't pick it up (presumably the same
>   applies to the installer). I've been told there are archive overrides
>   that might need updating as well: dear SRU team member, please check,
>   or ask an archive admin to check.
>
> To manage notifications about this bug go to:
>
> https://bugs.launchpad.net/ubuntu/+source/base-files/+bug/1888575/+subscriptions
>
> Launchpad-Notification-Type: bug
> Launchpad-Bug: distribution=ubuntu; sourcepackage=base-files;
> component=main; status=Fix Released; importance=Undecided; assignee=
> <email address hidden>;
> Launchpad-Bug: distribution=ubuntu; sourcepackage=livecd-rootfs;
> component=main; status=Invalid; importance=Undecided; assignee=None;
> Launchpad-Bug: distribution=ubuntu; sourcepackage=ubuntu-meta;
> component=main; status=Fix Released; importance=Undecided; assignee=
> <email address hidden>;
> Launchpad-Bug: distribution=ubuntu; distroseries=xenial;
> sourcepackage=base-files; component=main; status=Fix Released;
> importance=Undecided; <email address hidden>;
> Launchpad-Bug: distribution=ubuntu; distroseries=xenial;
> sourcepackage=livecd-rootfs; component=main; status=Triaged;
> importance=Undecided; assignee=None;
> Launchpad-Bug: distribution=ubuntu; distroseries=xenial;
> sourcepackage=ubuntu-meta; component=main; status=Fix Committed;
> importance=Undecided; <email address hidden>;
> Launchpad-Bug: distribution=ubuntu; distroseries=bionic;
> sourcepackage=base-files; component=main; status=Fix Released;
> importance=Undecided; <email address hidden>;
> Launchpad-Bug: distribution=ubuntu; distroseries=bionic;
> sourcepackage=livecd-rootfs; component=main; status=Invalid;
> importance=Undecided; assignee=None;
> Launchpad-Bug: distribution=ubuntu; distroseries=bionic;
> sourcepackage=ubuntu-meta; component=main; status=Fix Released;
> importance=Undecided; <email address hidden>;
> Launchpad-Bug: distribution=ubuntu; distroseries=focal;
> sourcepackage=base-files; component=main; status=Fix Released;
> importance=Undecided; <email address hidden>;
> Launchpad-Bug: distribution=ubuntu; distroseries=focal;
> sourcepackage=livecd-rootfs; component=main; status=Invalid;
> importance=Undecided; assignee=None;
> Launchpad-Bug: distribution=ubuntu; distroseries=focal;
> sourcepackage=ubuntu-meta; component=main; status=Fix Released;
> importance=Undecided; <email address hidden>;
> Launchpad-Bug: distribution=ubuntu; distroseries=groovy;
> sourcepackage=base-files; component=main; status=Fix Released;
> importance=Undecided; <email address hidden>;
> Launchpad-Bug: distribution=ubuntu; distroseries=groovy;
> sourcepackage=livecd-rootfs; component=main; status=Invalid;
> importance=Undecided; assignee=None;
> Launchpad-Bug: distribution=ubuntu; distroseries=groovy;
> sourcepackage=ubuntu-meta; component=main; status=Fix Released;
> importance=Undecided; <email address hidden>;
> Launchpad-Bug-Tags: verification-done-bionic verification-done-focal
> verification-needed verification-needed-xenial
> Launchpad-Bug-Information-Type: Public
> Launchpad-Bug-Private: no
> Launchpad-Bug-Security-Vulnerability: no
> Launchpad-Bug-Commenters: ahasenack janitor mvo ogra sil2100 tjaalton
> vorlon
> Launchpad-Bug-Reporter: Andreas Hasenack (ahasenack)
> Launchpad-Bug-Modifier: Oliver Grawert (ogra)
> Launchpad-Message-Rationale: Subscriber
> Launchpad-Message-For: ahasenack
>