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

Ulrich Windl Ulrich.Windl at rz.uni-regensburg.de
Thu Jan 18 02:22:17 EST 2018

>>> Ken Gaillot <kgaillot at redhat.com> schrieb am 17.01.2018 um 17:04 in Nachricht
<1516205099.5103.3.camel at redhat.com>:
> 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

s/the same/a common/ # if they were the same, there could be no differences

> instance is in one of two roles at any given time, and Pacemaker

two: just two or at least two?

> manages instances' roles via promote and demote actions.

NOw try to define what promote and demote do ;-)

> 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.

Maybe also state the purpose of having different roles here, and define what a role as opposed to a state is.

> 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.

"anonymous clone" should be defined also, just as unique: Aren't all configured resources "unique" (i.e. being different from each other)?

I'm curious about more than two roles, multiple "masters" and multiple "slaves".


> -- 
> Ken Gaillot <kgaillot at redhat.com>
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