group.of.nepali.translators team mailing list archive

[Nish Aravamudan <nish.aravamudan@xxxxxxxxxxxxx>]

** Changed in: supervisor (Ubuntu)
       Status: Confirmed => Fix Released

** Also affects: supervisor (Ubuntu Yakkety)
   Importance: Undecided
       Status: New

** Also affects: supervisor (Ubuntu Xenial)
   Importance: Undecided
       Status: New

** Changed in: supervisor (Ubuntu Yakkety)
       Status: New => Fix Released

** Changed in: supervisor (Ubuntu Xenial)
       Status: New => In Progress

** Changed in: supervisor (Ubuntu Xenial)
     Assignee: (unassigned) => Nish Aravamudan (nacc)

-- 
You received this bug notification because you are a member of नेपाली
भाषा समायोजकहरुको समूह, which is subscribed to Xenial.
Matching subscriptions: Ubuntu 16.04 Bugs
https://bugs.launchpad.net/bugs/1594740

Title:
  Supervisor not enabled or started in Ubuntu 16.04 after installation

Status in supervisor package in Ubuntu:
  Fix Released
Status in supervisor source package in Xenial:
  In Progress
Status in supervisor source package in Yakkety:
  Fix Released

Bug description:
  Expected behavior
  =================

  In Ubuntu 10.04, 12.04 and 14.04 after running "apt-get install
  supervisor" the Supervisor daemon is automatically enabled (to start
  on boot) and started (so that Supervisor is running by the time apt-
  get returns).

  What actually happens
  =====================

  In Ubuntu 16.04 the Supervisor daemon is not automatically enabled nor
  is it started during installation. This breaks compatibility with
  previous and expected behavior.

  Why this is a problem
  =====================

  I've built dozens of tools that use Supervisor for process supervision
  and these tools are deployed using custom Debian packages. Each of
  these packages has a dependency on the supervisor package with the
  expectation that Supervisor will be installed, enabled and started so
  that my post-installation scripts can call "supervisorctl" and expect
  it to work (instead of complaining about a missing UNIX socket file
  and exiting with a nonzero status code, thereby breaking my automated
  server provisioning).

  Known workaround
  ================

  Create a shim package with a dependency on supervisor and a post-
  installation script that runs the following commands:

      # On Ubuntu 16.04 the installation of Supervisor does not
      # enable and start the Supervisor daemon which breaks
      # compatibility with previous Ubuntu releases.
      if [ $(lsb_release --short --codename) = xenial ]; then
        # Make sure the daemon is enabled.
        if ! systemctl --quiet is-enabled supervisor; then
          systemctl enable supervisor
        fi
        # Make sure the daemon is started.
        if ! systemctl --quiet is-active supervisor; then
          systemctl start supervisor
        fi
      fi

  Alternatively one can obviously just run these commands by hand to
  rectify the situation.

  It's kind of nasty that I have to create a shim package like this to
  compensate for a break in backwards compatibility that is -as far as I
  know- undocumented and most likely unintentional. What's more is that
  a lot of people will lack the means to create shim packages like this,
  so thousands of Ubuntu users / integrators / system administrators
  worldwide will need to repeat these shenanigans manually.

  Affected versions
  =================

      peter@template-xenial:~$ lsb_release --short --description
      Ubuntu 16.04 LTS

      peter@template-xenial:~$ apt-cache policy supervisor
      supervisor:
        Installed: 3.2.0-2
        Candidate: 3.2.0-2
        Version table:
       *** 3.2.0-2 500
              500 http://mirror.nl.leaseweb.net/ubuntu xenial/universe amd64 Packages
              500 http://mirror.nl.leaseweb.net/ubuntu xenial/universe i386 Packages
              100 /var/lib/dpkg/status

  Root cause analysis
  ===================

  In Ubuntu 16.04 Supervisor is managed by systemd however the post-
  installation script is using update-rc.d and invoke-rc.d to enable and
  start Supervisor. As far as I know these commands are remnants of the
  old daemon management infrastructure and they don't integrate with
  systemd, hence the breakage:

      peter@template-xenial:~$ cat /var/lib/dpkg/info/supervisor.postinst 
      #!/bin/sh
      set -e

      # Automatically added by dhpython:
      if which pycompile >/dev/null 2>&1; then
        pycompile -p supervisor 
      fi

      # End automatically added section
      # Automatically added by dh_installinit
      if [ "$1" = "configure" ] || [ "$1" = "abort-upgrade" ]; then
        if [ -x "/etc/init.d/supervisor" ]; then
          update-rc.d supervisor defaults >/dev/null
        fi
        if [ -x "/etc/init.d/supervisor" ] || [ -e "/etc/init/supervisor.conf" ]; then
          invoke-rc.d supervisor start || exit $?
        fi
      fi
      # End automatically added section

  Conclusion
  ==========

  Is there a remote chance of getting this fixed in Ubuntu 16.06, maybe
  in a later point release? On the one hand I get that fixing this now
  is a big change compared to the original release of Ubuntu 16.04, on
  the other hand I have found dozens of unsuspecting users (see below)
  being bitten by this change in behavior and I haven't found a single
  user who appreciated it :-).

  If there is no chance of fixing this it should at least be documented
  in the release notes as a known regression, because I haven't been
  able to find any proper documentation about this change and I have
  found dozens of people being bitten by the break in backwards
  compatibility.

  External references
  ===================

  Some random reports of people running into (what I believe is) this
  exact issue:

  Here's an upstream bug report, where nothing can be fixed:
  https://github.com/Supervisor/supervisor/issues/735

  Here's an unhappy user wondering how to restore expected behavior:
  http://unix.stackexchange.com/questions/281774/ubuntu-server-16-04-cannot-get-supervisor-to-start-automatically

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/supervisor/+bug/1594740/+subscriptions