Model role partitions

[ianunruh]

If you notice in the diagram, there are 2 very distinct partitions of roles. They have load balancers and database on the outside, and then two duplicate partitions containing:

• Apache
• HAProxy
• Broxy
• Redis
• Dispatchers

In one place, the partitions talk to each other (HAProxy -> Broxy).

They took Redis, which can't be clustered, and effectively clustered it. We could do something like this by grouping roles together in a sort of "partition".