[CentOS] Just need to vent

Tue Jan 26 14:24:44 UTC 2016
Matthew Miller <mattdm at mattdm.org>

On Tue, Jan 26, 2016 at 11:51:29AM +0000, Peter Duffy wrote:
> I'm also still trying to figure out in what way systemd is supposed to
> be "better". I've seen the following things claimed for it:

Of the three things you list, hot-plug is certainly an important one.
But, it's not the big deal. The big deal is that systemd is not just a
fire-and-hope startup system, but a service manager. It knows which
processes came from where. That means it can:

* insure that when something is stopped, it's actually stopped. (If
  you've ever managed an HPC cluster and had processes escape the
  scheduler, you know this problem is real.)

* track process lifecycle, and restart (or take other action) on
  failure. (If software were perfect, this wouldn't be needed, but as
  is, this can save you being paged in the middle of the night.)

* actually securely connect output to the process it came from for
  logging -- both stdout/stderr and actual log messages. (This is why
  journald is closely integrated.)

There are other advantages (real dependency ordering, resource
management/reservation with cgroups, etc.), but process supervision is
the big deal. There are other alternative systems which _also_ do this,
but overall, Fedora, openSUSE, Arch, Debian, Ubuntu, and others
eventually decided that systemd was the technically best choice.

Matthew Miller
<mattdm at fedoraproject.org>
Fedora Project Leader