Public bug reported:
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
** Affects: supervisor (Ubuntu)
Importance: Undecided
Status: New
** Tags: supervisor systemd xenial
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1594740
Title:
Supervisor not enabled or started in Ubuntu 16.04 after installation
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/supervisor/+bug/1594740/+subscriptions
--
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
