I have a basic question related to RM of Yarn. Why is the allocate
container request to RM doesn't always return with containers. The call can
actually block and return when containers are available.
I launcher AM.
The AM requests for 5 containers.
The response returns without any containers.
I send the request for containers , again and again and the RM returns
containers (sometimes less than the number that I have asked for).
Is this something to do with the heartbeat as the allocate call must return
within a predictable time period?