[Bug 1888575] Re: Split motd-news config into a new package
Andreas Hasenack
1888575 at bugs.launchpad.net
Tue Aug 25 19:08:35 UTC 2020
Focal verification
This verification is quite long, given the amount of tests involved.
TL;DR All tests from (a) to (j) passed as required.
focal verification succeeded.
Details below.
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
Starting with:
ii base-files 11ubuntu5.1 amd64 Debian base system miscellaneous files
ii ubuntu-server 1.450.1 amd64 The Ubuntu Server system
With proposed enabled, an apt install base-files pulls in motd-news-config and upgrades ubuntu-server:
$ sudo apt install base-files
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
motd-news-config ubuntu-server
The following NEW packages will be installed:
motd-news-config
The following packages will be upgraded:
base-files ubuntu-server
(...)
And motd-news remains enabled:
ubuntu at focal-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
* Are you ready for Kubernetes 1.19? It's nearly here! Try RC3 with
sudo snap install microk8s --channel=1.19/candidate --classic
https://microk8s.io/ has docs and details.
ubuntu at focal-motd-news-split:~$ apt-cache policy base-files ubuntu-server motd-news-config
base-files:
Installed: 11ubuntu5.2
Candidate: 11ubuntu5.2
Version table:
*** 11ubuntu5.2 500
500 http://br.archive.ubuntu.com/ubuntu focal-proposed/main amd64 Packages
(...)
ubuntu-server:
Installed: 1.450.2
Candidate: 1.450.2
Version table:
*** 1.450.2 500
500 http://br.archive.ubuntu.com/ubuntu focal-proposed/main amd64 Packages
100 /var/lib/dpkg/status
(...)
motd-news-config:
Installed: 11ubuntu5.2
Candidate: 11ubuntu5.2
Version table:
*** 11ubuntu5.2 500
500 http://br.archive.ubuntu.com/ubuntu focal-proposed/main amd64 Packages
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
First, change /e/d/motd-news to disable the service:
ubuntu at focal-motd-news-split:~$ sudo sed -i 's,^ENABLED=.*,ENABLED=0,' /etc/default/motd-news
ubuntu at focal-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
ubuntu at focal-motd-news-split:~$
Confirm installed packages:
ubuntu at focal-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^i
dpkg-query: no packages found matching motd-news-config
ii base-files 11ubuntu5.1 amd64 Debian base system miscellaneous files
ii ubuntu-server 1.450.1 amd64 The Ubuntu Server system
Install base-files, which upgrades ubuntu-server, base-files, and installs the new motd-news-config package:
ubuntu at focal-motd-news-split:~$ sudo apt install base-files
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
motd-news-config ubuntu-server
The following NEW packages will be installed:
motd-news-config
The following packages will be upgraded:
base-files ubuntu-server
2 upgraded, 1 newly installed, 0 to remove and 15 not upgraded.
And confirm motd-news remains disabled (which was the modification done):
ubuntu at focal-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
ubuntu at focal-motd-news-split:~$
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
Starting from:
- unmodified config:
ubuntu at focal-motd-news-split:~$ dpkg -s base-files | grep /etc/default/motd-news ; md5sum /etc/default/motd-news
/etc/default/motd-news c08a329a603b640095da5ffe4e73491c
c08a329a603b640095da5ffe4e73491c /etc/default/motd-news
- ubuntu-server removed:
ubuntu at focal-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^i
dpkg-query: no packages found matching ubuntu-server
dpkg-query: no packages found matching motd-news-config
ii base-files 11ubuntu5.1 amd64 Debian base system miscellaneous files
apt install base-files upgrades just base-files, and /e/d/motd-news is removed, resulting in a disabled motd-news:
$ sudo apt install base-files
...
The following packages will be upgraded:
base-files
1 upgraded, 0 newly installed, 0 to remove and 15 not upgraded.
...
ubuntu at focal-motd-news-split:~$ ls -la /etc/default/motd-news
ls: cannot access '/etc/default/motd-news': No such file or directory
ubuntu at focal-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
ubuntu at focal-motd-news-split:~$
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
Starting point:
ubuntu at focal-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^i
dpkg-query: no packages found matching ubuntu-server
dpkg-query: no packages found matching motd-news-config
ii base-files 11ubuntu5.1 amd64 Debian base system miscellaneous files
ubuntu at focal-motd-news-split:~$ sudo sed -i 's,^ENABLED=.*,ENABLED=0,' /etc/default/motd-news
ubuntu at focal-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
ubuntu at focal-motd-news-split:~$
apt install base-files upgrades just base-files, and leaves a backup config file around. motd-news remains disabled since there is no config file:
$ sudo apt install base-files
...
The following packages will be upgraded:
base-files
1 upgraded, 0 newly installed, 0 to remove and 15 not upgraded.
...
ubuntu at focal-motd-news-split:~$ ls -la /etc/default/motd-news*
-rw-r--r-- 1 root root 682 Aug 25 18:42 /etc/default/motd-news.dpkg-bak
ubuntu at focal-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
ubuntu at focal-motd-news-split:~$
e) removing motd-news-config will also remove ubuntu-server (since it's a depends, and not a recommends)
Starting point:
ubuntu at focal-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^i
ii base-files 11ubuntu5.2 amd64 Debian base system miscellaneous files
ii motd-news-config 11ubuntu5.2 all Configuration for motd-news shipped in base-files
ii ubuntu-server 1.450.2 amd64 The Ubuntu Server system
ubuntu at focal-motd-news-split:~$ sudo apt remove motd-news-config
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
motd-news-config ubuntu-server
0 upgraded, 0 newly installed, 2 to remove and 15 not upgraded.
After this operation, 96.3 kB disk space will be freed.
Do you want to continue? [Y/n]
f) upgrading just ubuntu-server should pull motd-news-config in, and force-upgrade base-files
Starting point:
ubuntu at focal-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^i
dpkg-query: no packages found matching motd-news-config
ii base-files 11ubuntu5.1 amd64 Debian base system miscellaneous files
ii ubuntu-server 1.450.1 amd64 The Ubuntu Server system
ubuntu at focal-motd-news-split:~$ sudo apt install ubuntu-server
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
base-files motd-news-config
The following NEW packages will be installed:
motd-news-config
The following packages will be upgraded:
base-files ubuntu-server
2 upgraded, 1 newly installed, 0 to remove and 15 not upgraded.
Need to get 68.0 kB of archives.
After this operation, 45.1 kB of additional disk space will be used.
Do you want to continue? [Y/n]
g) Removing motd-news-server leaves /e/d/motd-news around; purging motd-news-server removes the /e/d/motd-news config file
Starting point for both cases:
ubuntu at focal-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^i
ii base-files 11ubuntu5.2 amd64 Debian base system miscellaneous files
ii motd-news-config 11ubuntu5.2 all Configuration for motd-news shipped in base-files
ii ubuntu-server 1.450.2 amd64 The Ubuntu Server system
ubuntu at focal-motd-news-split:~$ ls -la /etc/default/motd-news*
-rw-r--r-- 1 root root 682 Aug 7 20:02 /etc/default/motd-news
Remove:
ubuntu at focal-motd-news-split:~$ sudo apt remove motd-news-config
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
motd-news-config ubuntu-server
0 upgraded, 0 newly installed, 2 to remove and 15 not upgraded.
After this operation, 96.3 kB disk space will be freed.
Do you want to continue? [Y/n]
(Reading database ... 31277 files and directories currently installed.)
Removing ubuntu-server (1.450.2) ...
Removing motd-news-config (11ubuntu5.2) ...
ubuntu at focal-motd-news-split:~$ ls -la /etc/default/motd-news*
-rw-r--r-- 1 root root 682 Aug 7 20:02 /etc/default/motd-news
Purge:
ubuntu at focal-motd-news-split:~$ sudo apt purge motd-news-config
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
motd-news-config* ubuntu-server*
0 upgraded, 0 newly installed, 2 to remove and 15 not upgraded.
After this operation, 96.3 kB disk space will be freed.
Do you want to continue? [Y/n]
(Reading database ... 31277 files and directories currently installed.)
Removing ubuntu-server (1.450.2) ...
Removing motd-news-config (11ubuntu5.2) ...
(Reading database ... 31271 files and directories currently installed.)
Purging configuration files for motd-news-config (11ubuntu5.2) ...
ubuntu at focal-motd-news-split:~$ ls -la /etc/default/motd-news*
ls: cannot access '/etc/default/motd-news*': No such file or directory
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
Starting point:
ubuntu at focal-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^i
dpkg-query: no packages found matching motd-news-config
ii base-files 11ubuntu5.1 amd64 Debian base system miscellaneous files
ii ubuntu-server 1.450.1 amd64 The Ubuntu Server system
ubuntu at focal-motd-news-split:~$ sudo rm /etc/default/motd-news
ubuntu at focal-motd-news-split:~$ ls -la /etc/default/motd-news*
ls: cannot access '/etc/default/motd-news*': No such file or directory
ubuntu at focal-motd-news-split:~$
Install base-files:
ubuntu at focal-motd-news-split:~$ sudo apt install base-files
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
motd-news-config ubuntu-server
The following NEW packages will be installed:
motd-news-config
The following packages will be upgraded:
base-files ubuntu-server
2 upgraded, 1 newly installed, 0 to remove and 15 not upgraded.
(...)
/e/d/motd-news is created with ENABLED=0 and a note stating why:
ubuntu at focal-motd-news-split:~$ head /etc/default/motd-news -n 7
# Enable/disable the dynamic MOTD news service
# This is a useful way to provide dynamic, informative
# information pertinent to the users and administrators
# of the local system
# Changed by motd-news-config.postinst:
# config file was manually removed - disable the service
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
Starting point:
ubuntu at focal-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^i
dpkg-query: no packages found matching ubuntu-server
dpkg-query: no packages found matching motd-news-config
ii base-files 11ubuntu5.1 amd64 Debian base system miscellaneous files
ubuntu at focal-motd-news-split:~$ sudo rm /etc/default/motd-news
ubuntu at focal-motd-news-split:~$ ls -la /etc/default/motd-news*
ls: cannot access '/etc/default/motd-news*': No such file or directory
Install base-files, just base-files is upgraded, and no /e/d/motd-news file is created:
ubuntu at focal-motd-news-split:~$ sudo apt install base-files
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be upgraded:
base-files
1 upgraded, 0 newly installed, 0 to remove and 15 not upgraded.
ubuntu at focal-motd-news-split:~$ ls -la /etc/default/motd-news*
-rw-r--r-- 1 root root 0 Aug 25 18:54 /etc/default/motd-news.wasremoved
As noted in the SRU bug for this test case, a ".wasremoved" zero-sized
file is left around, but 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)
Starting point, with focal-proposed disabled (since groovy already has these changes proposed here):
$ dpkg -l base-files ubuntu-server motd-news-config | grep ^i
dpkg-query: no packages found matching ubuntu-server
dpkg-query: no packages found matching motd-news-config
ii base-files 11ubuntu5.1 amd64 Debian base system miscellaneous files
ubuntu at focal-motd-news-split:~$ dpkg -s base-files | grep /etc/default/motd-news ; md5sum /etc/default/motd-news
/etc/default/motd-news c08a329a603b640095da5ffe4e73491c
c08a329a603b640095da5ffe4e73491c /etc/default/motd-news
ubuntu at focal-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
* Are you ready for Kubernetes 1.19? It's nearly here! Try RC3 with
sudo snap install microk8s --channel=1.19/candidate --classic
https://microk8s.io/ has docs and details.
$ sudo do-release-upgrade -d
...
State at the end:
ubuntu at focal-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^i
dpkg-query: no packages found matching motd-news-config
ii base-files 11ubuntu12 amd64 Debian base system miscellaneous files
ubuntu at focal-motd-news-split:~$ apt-cache policy base-files
base-files:
Installed: 11ubuntu12
Candidate: 11ubuntu12
Version table:
*** 11ubuntu12 500
500 http://br.archive.ubuntu.com/ubuntu groovy/main amd64 Packages
100 /var/lib/dpkg/status
motd-news disabled (also tested after a reboot):
ubuntu at focal-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
ubuntu at focal-motd-news-split:~$ echo $?
0
ubuntu at focal-motd-news-split:~$ ls -la /etc/default/motd-news*
ls: cannot access '/etc/default/motd-news*': No such file or directory
** Tags removed: verification-needed-focal
** Tags added: verification-done-focal
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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 ubuntu-meta package in Ubuntu:
Fix Released
Status in base-files source package in Xenial:
Fix Committed
Status in ubuntu-meta source package in Xenial:
Fix Committed
Status in base-files source package in Bionic:
Fix Committed
Status in ubuntu-meta source package in Bionic:
Fix Committed
Status in base-files source package in Focal:
Fix Committed
Status in ubuntu-meta source package in Focal:
Fix Committed
Status in base-files source package in Groovy:
Fix Released
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)
[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.
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