[systemd-devel] mysqld about back to use mysqld_safe in Fedora

[Lennart Poettering]

On Thu, 28.06.12 09:41, Honza Horak (hhorak at redhat.com) wrote:

> 
> On 06/27/2012 07:01 PM, Lennart Poettering wrote:
> >Hmm, well, not really. "on-abort" means that systemd would only restart
> >the service on actual crashes, i.e. where the main process exits with a
> >signal like SIGSEGV, SIGBUS or SIGABRT. This is different from
> >"on-failure" which is the behaviour you describe where we'd also restart
> >the service if it exists with a non-zero exit code.
> >
> >I am pretty sure "on-abort" is actually what you really want here, no?
> >The PID file checking sounds like a hack to achieve the same?
> 
> Not really, there are cases where mysqld notices fatal problems,
> gives up and crashes without a signal with exit-code 1. In this case
> we want still to restart it. On the other hand there are cases where
> mysqld cleans up and still returns 1. In this case we don't want to
> restart it (wrong configuration is one example). I don't see this as
> the best design, but changing it would be too painful. Since we'd
> like to preserve current/upstream's behavior, it seems better to let
> the whole auto-restarting thing to mysqld_safe script.

Hmm, so I#d guess it would actually really be worth fixing the return
codes of MySQL. I mean, this is not really systemd-only thing. I'd
expect that the Upstart folks and the SMF folks would be really
interested in having reliable exit codes, too?

> >An alternative, more modern way to handle all this is by simply using
> >Type=notify and invoking sd_notify("READY=1"); in the daemon when
> >everything is done. This should normally be a two line patch and makes
> >PID files entirely redundant.
> 
> sd_notify seems to work fine, though a SELinux rule would have to be
> added. I'll prepare a patch and try to offer it to upstream, but as
> Tom said, we shouldn't expect much interest.

Thanks!

Lennart

-- 
Lennart Poettering - Red Hat, Inc.