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 [ $(lsb_release --short --codename) = xenial ]; then
# Make sure the daemon is enabled.
if ! systemctl --quiet is-enabled supervisor; then
systemctl enable supervisor
fi
# Make sure the daemon is started.
if ! systemctl --quiet is-active supervisor; then
systemctl start supervisor
fi
fi
Alternatively one can obviously just run these commands by hand to rectify the situation.
It's kind of nasty that I have to create a shim package like this to compensate for a break in backwards compatibility that is -as far as I know- undocumented and most likely unintentional. What's more is that a lot of people will lack the means to create shim packages like this, so thousands of Ubuntu users / integrators / system administrators worldwide will need to repeat these shenanigans manually.
In Ubuntu 16.04 Supervisor is managed by systemd however the post-installation script is using update-rc.d and invoke-rc.d to enable and start Supervisor. As far as I know these commands are remnants of the old daemon management infrastructure and they don't integrate with systemd, hence the breakage:
peter@template-xenial:~$ 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:
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 mirror. nl.leaseweb. net/ubuntu xenial/universe amd64 Packages mirror. nl.leaseweb. net/ubuntu xenial/universe i386 Packages dpkg/status
supervisor:
Installed: 3.2.0-2
Candidate: 3.2.0-2
Version table:
*** 3.2.0-2 500
500 http://
500 http://
100 /var/lib/
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 d/supervisor" ]; then d/supervisor" ] || [ -e "/etc/init/ supervisor. conf" ]; then
# Automatically added by dh_installinit
if [ "$1" = "configure" ] || [ "$1" = "abort-upgrade" ]; then
if [ -x "/etc/init.
update-rc.d supervisor defaults >/dev/null
fi
if [ -x "/etc/init.
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: /github. com/Supervisor/ supervisor/ issues/ 735
https:/
Here's an unhappy user wondering how to restore expected behavior: unix.stackexcha nge.com/ questions/ 281774/ ubuntu- server- 16-04-cannot- get-supervisor- to-start- automatically
http://