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Re: Systemd



On Sat, Apr 26, 2014 at 1:21 AM, Ólafur Jens Sigurðsson
<ojsbug@gmail.com> wrote:
> It would be nice to see a comparison of features without any kind of
> judgement of each merit or con.
>
> As soon as people start saying "this feature is better then that one"
> that's when the cat gets loose I think, no trolling needed, just stating
> oppinions is enough. We all have our oppinions but there are some
> technical differences between sysvinit and systemd that would be nice to
> have.

Well, we have a fine generic subject line for this. I'll start by
saying what I like about each of sysvinit and Upstart, and what my
understanding is of systemd based on docs readings. Please, folks, no
trolling, but just good clean discussion!

1) sysvinit works with all the existing scripts that have been around
for donkey's years. I understand systemd happily reads them, although
I'm not sure if the top comment block is a requirement for that. (With
Upstart, this isn't the case. I had to craft Upstart job files for
services like Apache and PostgreSQL before I could have my own
services depend on them.)

2) Upstart job files are easy to write, and follow an efficient
declarative style ("setuid blah", "start on net-device-up"). A systemd
config file is also fairly clean and declarative.

3) Upstart manages job lifetimes completely, including following
processes through forking and daemonization. AIUI systemd does the
same.

4) Upstart dependencies can be described fairly simply ("start on
started foobar" will start this service when foobar finishes
starting). Systemd goes further and actually records that this depends
on that, rather than just firing one and then another.

5) Upstart parallelizes boot. If two jobs depend on the same parent
and have no inter-dependencies, they'll be started simultaneously.
Systemd does the same.

Let the corrections and additions begin!

ChrisA


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