cgroup-lite can not be installed with systemd

I'm sorry, but I don't know what you mean by a missing upstart service. If you can post a debdiff with the fix I'll happily test and push it, thanks.

I mean if systemd is installed and used instead of upstart, then we can not install the package.

More concretely, cgroups-mount/umount and the corresponding upstart job aren't necessary at all under systemd. So the only thing to do here is to provide a no-op "placeholder" cgroup-lite.service to satisfy invoke-rc.d.

On top of that, invoke-rc.d currently fails if a unit is masked. This needs to be fixed, too.

This bug was fixed in the package cgroup-lite - 1.10

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cgroup-lite (1.10) utopic; urgency=medium

  * Add masked dummy cgroup-lite.service to avoid package install/upgrade
    failure when running under systemd. We don't need this job under systemd.
    (LP: #1312975)
 -- Martin Pitt <email address hidden> Mon, 12 May 2014 11:00:59 +0200

Even with the fixed invoke-rc.d (sysv-rc 2.88dsf-41ubuntu10 in utopic-proposed), I still can’t upgrade cgroup-lite:

Preparing to unpack .../cgroup-lite_1.10_all.deb ...
Failed to issue method call: Unit cgroup-lite.service not loaded.
invoke-rc.d: initscript cgroup-lite, action "stop" failed.
dpkg: warning: subprocess old pre-removal script returned error exit status 5
dpkg: trying script from the new package instead ...
Failed to issue method call: Unit cgroup-lite.service not loaded.
invoke-rc.d: initscript cgroup-lite, action "stop" failed.
dpkg: error processing archive /var/cache/apt/archives/cgroup-lite_1.10_all.deb (--unpack):
 subprocess new pre-removal script returned error exit status 5
Failed to issue method call: Unit cgroup-lite.service failed to load: No such file or directory. See system logs and 'systemctl status cgroup-lite.service' for details.
invoke-rc.d: initscript cgroup-lite, action "start" failed.
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 6
Errors were encountered while processing:
 /var/cache/apt/archives/cgroup-lite_1.10_all.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install. Trying to recover:
dpkg: error processing package cgroup-lite (--configure):
 package is in a very bad inconsistent state; you should
 reinstall it before attempting configuration
Errors were encountered while processing:
 cgroup-lite

This is really a chicken-and-egg problem. We can't upgrade from packages which only have upstart jobs when already running systemd, or at least not with what we have right now. Upgrades need to happen under upstart until packages get fixed for systemd support, and from then on it will work under systemd as well (I tried with --reinstall, and works fine).

When the old package’s prerm fails, dpkg goes back and runs the new package’s prerm instead, to allow us to escape exactly that kind of chicken-and-egg problem. We could, for example, have the new prerm create the cgroup-lite.service → /dev/null symlink if it isn’t already there.

This bug was fixed in the package sysvinit - 2.88dsf-41ubuntu10

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sysvinit (2.88dsf-41ubuntu10) utopic; urgency=medium

  * invoke-rc.d: Don't fail on masked services. (LP: #1312975)
 -- Martin Pitt <email address hidden> Mon, 12 May 2014 11:20:50 +0200