[systemd-devel] SysVInit service migration to systemd

[Reindl Harald]

Am 29.06.2015 um 15:58 schrieb Lesley Kimmel:
> Jonathan;
>
> Thanks for the background and information. Since you clearly seem to
> have a grasp of systemd please humour me with a few more questions (some
> of them slightly ignorant):
>
> a) Why are PID bad?

what are they good for when the supervisor knows the PID to monitor?

> b) Why are lock files bad?

what are they good for when the supervisor knows the state of each service

> c) If a/b are so bad why did they persist for so many years in SysVInit?

because SysVInit did have no other way to know the PID or if a service 
is running and things like lockfiles are far away from safe when the 
application crashs and don't remove them - often enough that a restart 
of services failed because of that

> d) Generically, how would you prescribe to use systemd to start Java
> processes (for Java application servers) that are typically started from
> a set of relatively complex scripts that are used to set up the
> environment before launching the Java process? It seems that you are
> advocating to call, as directly as possible, the target service/daemon.
> However, some things don't seem so straight-forward.

most complexity in that scripts is because the way SysVInit worked

a daemon should read each configuration files and not need more than the 
argument of the config file as param

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