[Pacemaker] Best way to split a resource across two locations, four nodes

[Andy Smith]

Hi,

After having only used heartbeat a few years ago I'm now starting to
look at the newer version, with pacemaker. I'm running the 3.0.3-2
Debian packages on either lenny-backports or squeeze.

This is all new to me so I'd be grateful if you could check some of
my assumptions here.

For now I'm interested in clustering DNS resolvers. Anycast might be
technically better for this but the environment I'm working with
won't support that for some time yet.

I have hardware in two different suites of a datacentre and I would
like to offer two different resolver IPs to clients, so I'm thinking
the best way to do this would be (at least) four nodes, two in each
suite:

node a, suite 1
node b, suite 2
node c, suite 1
node d, suite 2

I would then have a ResolverIP1 resource that could run on nodes "a"
or "b" but prefers node "a", and a ResolverIP2 resource that could run
on nodes "c" or "d" but prefers node "d". That way under ideal
circumstances ResolverIP1 I believe would exist on some node in
suite 1 whilst ResolverIP2 would exist on some node in suite 2,
right?

Should an entire suite go dark (e.g. power fail of whole room), I
would still like for the less-preferred layout of ("a" and "c") or
("b" and "d") to happen.

Is this the simplest way to achieve what I want?

Since DNS is largely stateless I suppose I could do something with a
cloned resource, but I do want two different IP addresses to be
presented so it seems to me that the above way is simplest.

If I wanted the clusters to reconfigure resources back to preferred
layout after a suite came back, would I just need to make sure to
have the location score higher than the stickiness score?

Cheers,
Andy