We envision a management system where human operators can set up and tear down clusters for S4 tasks, and
perform other administrative operations.
The assignment of physical nodes to these S4 task clusters is coordinated using ZooKeeper .
A subset of active nodes are assigned to particular tasks, while the remaining idle nodes remain in a pool which can be used as needed (e.g. failover, or dynamic load balancing).
In particular, an idle node may be registered as a standby for multiple active nodes which may be assigned to distinct tasks