I've taken the view of treating our database slaves as special and allocating all the memory on the slave to ES. That way ES (or any other db) always runs on the right slave, and no other potentially long running/resource hungry process runs alongside it (but just enough that's jenkins tasks and chronos tasks can still rune if need be).

AKAIK, there isn't a right way to run databases because the persistent storage layer into mesos is still being baked.