[ClusterLabs] Possible idea for 2.0.0: renaming the Pacemaker daemons

Digimer lists at alteeve.ca
Wed Mar 28 15:31:33 EDT 2018

On 2018-03-28 01:40 PM, Ken Gaillot wrote:
> Hi all,
> Andrew Beekhof brought up a potential change to help with reading
> Pacemaker logs.
> Currently, pacemaker daemon names are not intuitive, making it
> difficult to search the system log or understand what each one does.
> The idea is to rename the daemons, with a common prefix, and a name
> that better reflects the purpose.
> I think it's a great idea, but we have to consider two drawbacks:
> * I'm about to release 2.0.0-rc2, and it's late in the cycle for a
> major change. But if we don't do it now, it'll probably sit on the back
> burner for a few years, as it wouldn't make sense to introduce such a
> change shortly after a major bump.

I would do it now. Everyone is preparing for updates to support, now is
the time to break things.

> * We can change *only* the names used in the logs, which will be
> simple, but give us inconsistencies with what shows up in "ps", etc. Or
> we can try to change everything -- process names, library names, API
> function/structure names -- but that will impact other projects such as
> sbd, crmsh, etc., potentially causing compatibility headaches.

I think consistency is key, so I would change everything to match.
Having ps show one thing and logs show another will cause trouble later.

> What are your thoughts? Change or not? Now or later? Log tags, or
> everything?
> And the fun part, what would we change them to ...
> Beekhof suggested renaming "pengine" to "cluster-planner", as an
> example.
> I think a prefix indicating pacemaker specifically would be better than
> "cluster-" for grepping and intuitiveness.

"Cluster" is pretty generic, I vote for "pacemaker".

> For intuitiveness, long names are better ("pacemaker-FUNCTION"). On the
> other hand, there's an argument for keeping names to 15 characters,
> which is the default "ps" column width, and a reasonable limit for log
> line tags. Maybe "pm-" or "pcmk-"? This prefix could also be used for
> library names.

If you need to shorten it, 'pcmk-' has been a long-established standard.

> Looking at other projects with server processes, most use the
> traditional "d" ending (for example, "rsyslogd"). A few add "-daemon"
> ("rtkit-daemon"), and others don't bother with any suffix ("gdm").
> Here are the current names, with some example replacements:
>  pacemakerd: PREFIX-launchd, PREFIX-launcher
>  attrd: PREFIX-attrd, PREFIX-attributes
>  cib: PREFIX-configd, PREFIX-state
>  crmd: PREFIX-controld, PREFIX-clusterd, PREFIX-controller
>  lrmd: PREFIX-locald, PREFIX-resourced, PREFIX-runner
>  pengine: PREFIX-policyd, PREFIX-scheduler
>  stonithd: PREFIX-fenced, PREFIX-stonithd, PREFIX-executioner
>  pacemaker_remoted: PREFIX-remoted, PREFIX-remote

The 'd' suffix is a well-established standard.

My $0.02.

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