man-db without cache update (no cron or systemd *.timer)

Lars Kellogg-Stedman lars at redhat.com
Tue Oct 21 17:04:45 UTC 2014


On Mon, Oct 20, 2014 at 08:56:19PM +0200, Lennart Poettering wrote:
> Hmm, not sure I follow here. Since when is systemd an optional
> component in Fedora?

I have been spending much of my time building Fedora-based Docker
containers recently.  I've been sticking to the
one-process-per-container model because I think it brings a number of
advantages.  One of the biggest, in my opinion, is that "container
management" reduces to "process management", and I already have a
great process manager on my host.  It's called "systemd".

Decomposing an application into single-process containers also means
that it's easier to scale individual components.  *And* for many
applications -- those that can log to stderr/stdout -- it means
that application logs show up in my host journal *where I want them*.

Running any sort of process manager inside the container can also have
the unintended side-effect of hiding problems from the host.  If an
application is failing to start because of a configuration issue, I
don't want that managed inside the container -- I want the host to be
aware of that so that higher-level mechanisms can be involved.  I want
a host- or cluster- level container manager to be able to restart
dependent containers, or to have the opportunity to reschedule a
container on another host.

I think it is absolutely essential that systemd is *able* to run
inside a container -- because I think there are invariably going to be
situations in which the one-process-per-container model simply doesn't
pan out.  But I also think that in many situations it is not required
and using systemd inside the container simply complicates things.

-- 
Lars Kellogg-Stedman <lars at redhat.com> | larsks @ {freenode,twitter,github}
Cloud Engineering / OpenStack          | http://blog.oddbit.com/

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