capacity-scheduler scheduling

daemon thread to pick up the candidates nodemanagers. see: Attachment
and then use the single nodemanager to find out the candidate queue + apps
- find out the priority children queues. see Attachment
  1. first factor: priority
  2. second factor: abs used capacity (The queue with less relative used-capacity goes first)
- find out the sorted apps submitted to upper queue. see: Attachment
  1. getting the apps from the specified sorting policies

Question

queue selection is selected by the abs used capacity, when to sub/add used capacity

Only when the container is allocated successfully in the async scheduling commit process, the allocated resource will be added into the queue’s usage resources. Please see Resource deductions associated code

BTW, if the container is allocated, it will notify the app’s ordering policy to reorder the associated app. Detailed code is leaf queue.

orderingPolicy.containerAllocated(  
schedulerContainer.getSchedulerApplicationAttempt(),  
schedulerContainer.getRmContainer());

Is it possible that race condition happens when multi thread to propose commit for the same apps or queue

I think yes, multi threads will choose the same queue and then to get the same apps to allocate. From the sorting policy, I don’t see any avoidance strategies.