Installation fails when files associated to package ubuntu-advantage-tools have local changes (e.g. juju managed files)

[Jose Guedez]

While replacing the `canonical-livepatch` charm for `ubuntu-advantage` the units hit errors, due to for example juju managed logrotate configurations.

Using current edge channel, code seems to match commit 5d93cdba18d77c1562c7e7542ac280bc47dfdb17

For example:

(initial install of canonical-livepatch, also with a logrotated subordinate)
juju remove-relation <app>:juju-info canonical-livepatch:juju-info # units are removed cleanly
juju add-relation <app>:juju-info ubuntu-advantage:juju-info

The new ubuntu-advantage/X unit enters ERROR state with this stacktrace:

2022-02-25 03:50:14 INFO unit.ubuntu-advantage/0.juju-log server.go:327 Installing package ubuntu-advantage-tools
2022-02-25 03:50:15 WARNING unit.ubuntu-advantage/0.config-changed logger.go:60 WARNING: apt does not have a stable CLI interface. Use with caution in scripts.
2022-02-25 03:50:17 WARNING unit.ubuntu-advantage/0.config-changed logger.go:60 E: Sub-process /usr/bin/dpkg returned an error code (1)
2022-02-25 03:50:17 ERROR unit.ubuntu-advantage/0.juju-log server.go:327 Uncaught exception while in charm code:
Traceback (most recent call last):
  File "./src/charm.py", line 170, in <module>
    main(UbuntuAdvantageCharm)
  File "/var/lib/juju/agents/unit-ubuntu-advantage-0/charm/venv/ops/main.py", line 402, in main
    _emit_charm_event(charm, dispatcher.event_name)
  File "/var/lib/juju/agents/unit-ubuntu-advantage-0/charm/venv/ops/main.py", line 140, in _emit_charm_event
    event_to_emit.emit(*args, **kwargs)
  File "/var/lib/juju/agents/unit-ubuntu-advantage-0/charm/venv/ops/framework.py", line 278, in emit
    framework._emit(event)
  File "/var/lib/juju/agents/unit-ubuntu-advantage-0/charm/venv/ops/framework.py", line 722, in _emit
    self._reemit(event_path)
  File "/var/lib/juju/agents/unit-ubuntu-advantage-0/charm/venv/ops/framework.py", line 767, in _reemit
    custom_handler(event)
  File "./src/charm.py", line 89, in config_changed
    self._handle_package_state()
  File "./src/charm.py", line 121, in _handle_package_state
    install_package("ubuntu-advantage-tools")
  File "./src/charm.py", line 34, in install_package
    subprocess.check_call(["apt", "install", "--yes", "--quiet", package])
  File "/usr/lib/python3.8/subprocess.py", line 364, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['apt', 'install', '--yes', '--quiet', 'ubuntu-advantage-tools']' returned non-zero exit status 100.

Running the command manually shows the actual error which is that file `/etc/logrotate.d/ubuntu-advantage-tools` has been modified by juju. Perhaps it would be convenient to install the package with `-o Dpkg::Options::="--force-confold"` to preserve the juju changes.

root@prometheus-3:~# apt install ubuntu-advantage-tools
Reading package lists... Done
Building dependency tree
Reading state information... Done
ubuntu-advantage-tools is already the newest version (27.6~20.04.1).
0 upgraded, 0 newly installed, 0 to remove and 45 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n]
Setting up ubuntu-advantage-tools (27.6~20.04.1) ...

Configuration file '/etc/logrotate.d/ubuntu-advantage-tools'
 ==> Modified (by you or by a script) since installation.
 ==> Package distributor has shipped an updated version.
   What would you like to do about it ? Your options are:
    Y or I : install the package maintainer's version
    N or O : keep your currently-installed version
      D : show the differences between the versions
      Z : start a shell to examine the situation
 The default action is to keep your current version.
*** ubuntu-advantage-tools (Y/I/N/O/D/Z) [default=N] ? D
--- /etc/logrotate.d/ubuntu-advantage-tools 2022-02-25 03:17:03.798595388 +0000
+++ /etc/logrotate.d/ubuntu-advantage-tools.dpkg-new 2022-01-20 21:02:27.000000000 +0000
@@ -1,6 +1,8 @@
-# Configuration file maintained by Juju. Local changes may be overwritten
-/var/log/ubuntu-advantage.log {
- rotate 1
+# use the root group by default, since this is the owning group
+# of /var/log/ubuntu-advantage*.log files.
+/var/log/ubuntu-advantage*.log {
+ su root root
+ rotate 6
     monthly
     compress
     delaycompress

[Tom Haddon (mthaddon)]

I've released revision 17 to the edge channel which should address this. Please give it a try and confirm, once we've done that we can promote that release to the stable channel.