Affects Version/s: 0.9.0
Fix Version/s: 0.9.0
Before implementing a scheduler, I think we should do some refactoring at first. There are 2 interfaces and 4 classes related to resource management, they are WorkerResourceManager , YarnTajoResourceManager, TajoWorkerResourceManager reside in TajoMaster, and ResourceAllocator, YarnResourceAllocator, TajoResourceAllocator reside in QueryMasters.
WorkerResourceManager actually plays 3 roles
1. Choose or start a QueryMaster for a query, and management it
2. allocate resource for query tasks / task runners (only for standalone mode)
3. Handle worker's heartbeat (only for standalone mode)
If the scheduler is a decentralized one, like sparrow, we can allocate resource for a QueryMaster as the same way for a TaskRunner. So 1. and 2. can use the same interface, but called by 2 different caller. 3. is different from the others, we can create another service, let's say HeartbeatService to deal with worker's heartbeats.