** Description changed: + [Impact] + + * In all prior releases to 16.04, `apt-get install supervisor` would + result in supervisor being started after package installation (and + configured to start by default at boot). This is the principle of least + surprise in action and reflects Ubuntu's ease of use. + + * Due to the timing of 16.04, the version from Debian was broken to not + support systemd properly. + + * Both Debian and Ubuntu have been fixed since the version in 16.04, in + the same way as the proposed fix. + + [Test Case] + + * Install supervisor. After installation, the service should be running + and should be enabled. + + [Regression Potential] + + * As the behavior is currently regressed relative to 14.04, I believe + the primary potential source of regressions will be users who have + manually fixed-up systemd to do what was expected on their systems. I + believe dpkg will notice the differences, if any, between the system- + installed supervisor systemd files and those in this package. + + --- + 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 16.04, 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
-- 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 [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
