[Pacemaker] Postgresql streaming replication failover - RAneeded

[Buckingham, Brett]

> Well I'm not sure I would be able to do that change. Failover is
relatively easy to do but I really have no idea how to do the failback
part.

>And that's exactly the reason why I haven't implemented it yet. With
the current way how replication is done in PostgreSQL there is no easy
way to switch between roles, or at least I don't know about a such way.
Implementing just fail-over functionality by creating a trigger file on
a slave server in the case of failure on master side doesn't create a
full master-slave implementation in my opinion.

We have created just such a multi-state RA, which incorporates a design
to manage failover, failback, and fallback (regular backups).  Please
give us a few days - a member of my team is removing any
product-specifics from it, and we'll post it shortly.

Brett