Bug#750683: systemd: oneshot services get started more than once

[Uoti Urpala]

Ed Swierk wrote:
> I found that adding RemainAfterExit=yes to the service file prevents
> this from happening. But nothing in the systemd documentation (nor in
> the code, to the extent I understand it) indicates that this is
> necessary for oneshot services.

This has been a known issue for some services, and has been fixed for at
least some of them upstream by adding RemainAfterExit. Without
RemainAfterExit, when another service is started and depends on the
oneshot service (directly or indirectly, typically by depending on
something like basic.target which depends on the oneshot), systemd will
not consider the oneshot to be already active if it has finished
executing and exited, and it will thus be started again.

Is this really v208? systemd-random-seed.service in v208 DOES have
RemainAfterExit=yes. The version in v204 did trigger this issue, but
it's set up differently and the part which could trigger is named
systemd-random-seed-load.service.