Comment 9 for bug 1400394

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Martin Pitt (pitti) wrote : Re: Unity8 fails to start applications under systemd init (cgmanager issue?)

We discussed that again via email. In summary:

 - UAL and systemd units are non-overlapping use cases, and will not collide at all in practical use cases.
 - By itself, systemd only handles the "systemd" controller, which cgmanager should always stay out of
 - systemd units may configure cpu/memory/blkio cgroups with things like CPUShares=; so in principle, the started service could then do a cgmanager call to change these after the fact, but there's nothing stopping it from also doing these changes in /sys/fs/cgroup/ directly. This isn't a security feature, but a robustness/resource control one.

So what needs to happen:

 1. Ensure cgmanager doesn't change the "systemd" controller. (Should not happen in practice, but an explicit check can't hurt)
 2. Ensure cgmanager doesn't change an existing cgroup setup at startup, only upon request (which should already be true)
 3. Start cgmanager via socket/bus activation or at boot.