[ClusterLabs] Antw: Feedback wanted: changing "master/slave" terminology

Ken Gaillot kgaillot at redhat.com
Wed Jan 17 11:04:59 EST 2018

On Wed, 2018-01-17 at 08:32 +0100, Ulrich Windl wrote:
> > > > Ken Gaillot <kgaillot at redhat.com> schrieb am 16.01.2018 um
> > > > 23:33 in Nachricht
> <1516142036.5604.3.camel at redhat.com>:
> > As we look to release Pacemaker 2.0 and (separately) update the OCF
> > standard, this is a good time to revisit the terminology and syntax
> > we
> > use for master/slave resources.
> > 
> > I think the term "stateful resource" is a better substitute for
> > "master/slave resource". That would mainly be a documentation
> > change.
> If there will be exactly two states, it'll be bi-state resource, and
> when abandoning the name, you should also abandon names like promote
> and demote, because they stick to master/slave.
> So maybe start with describing what a stateful resource is, then talk
> about names.
> BTW: All resoiucres we have are "stateful", because they can be in
> started and stopped states at least ;-)

Good points.

A clone is a resource with a configurable number of instances using the
same resource configuration. When a clone is stateful, each active
instance is in one of two roles at any given time, and Pacemaker
manages instances' roles via promote and demote actions.

Too bad "roleful" isn't a word ;-)

As you mentioned, "state" can more broadly refer to started, stopped,
etc., but pacemaker does consider "started in slave role" and "started
in master role" as extensions of this, so I don't think "stateful" is
too far off the mark.

Separately, clones (whether stateful or not) may be anonymous or unique
(i.e. whether it makes sense to start more than one instance on the
same node), which confuses things further.
Ken Gaillot <kgaillot at redhat.com>

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