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

[Jehan-Guillaume de Rorthais]

On Tue, 03 Apr 2018 16:35:18 -0500
Ken Gaillot <kgaillot at redhat.com> wrote:

> On Tue, 2018-04-03 at 08:33 +0200, Kristoffer Grönlund wrote:
> > Ken Gaillot <kgaillot at redhat.com> writes:
> >   
> > > > I
> > > > would vote against PREFIX-configd as compared to other cluster
> > > > software,
> > > > I would expect that daemon name to refer to a more generic
> > > > cluster
> > > > configuration key/value store, and that is something that I have
> > > > some
> > > > hope of adding in the future ;) So I'd like to keep "config" or
> > > > "database" for such a possible future component...  
> > > 
> > > What's the benefit of another layer over the CIB?
> > >   
> > 
> > The idea is to provide a more generalized key-value store that other
> > applications built on top of pacemaker can use. Something like a
> > HTTP REST API to a key-value store with transactional semantics
> > provided
> > by the cluster. My understanding so far is that the CIB is too heavy
> > to
> > support that kind of functionality well, and besides that the
> > interface
> > is not convenient for non-cluster applications.  
> 
> My first impression is that it sounds like a good extension to attrd,
> cluster-wide attributes instead of node attributes. (I would envision a
> REST API daemon sitting in front of all the daemons without providing
> any actual functionality itself.)
> 
> The advantage to extending attrd is that it already has code to
> synchronize attributes at start-up, DC election, partition healing,
> etc., as well as features such as write dampening.

I feel like you guys are talking of a solution that already exists and you
probably already know, eg. "etcd".

Etcd provides:

* a cluster wide key/value storage engine
* support quorum
* key locking
* atomic changes
* REST API
* etc...

However, it requires to open a new TCP port, indeed :/

Moreover, as a RA developer, I am currently messing with attrd weird
behavior[1], so any improvement there is welcomed :)

Cheers,

[1] https://github.com/ClusterLabs/PAF/issues/131