Apache Hadoop by default uses FIFO scheduling (That I will explain you In my coming post) and 5 scheduling priorities to schedule jobs from job queue(I think we should sometime arrange operating system tutorials) .
In version 0.19 job scheduler was re factored out of Job Tracker and other alternative scheduler were used in place of it .
1. Fair Scheduler - The fair scheduler was developed by Facebook with a main aim to provide fast response times for small jobs and QoS(Quality Of Service) for production jobs.
The fair scheduler has three key features:
a) Jobs are grouped into pools.
b) Each pool is assigned a guaranteed minimum share.
c) Excess capacity is split between jobs.
By default, jobs that are uncategorized go into a default pool.
2. Capacity scheduler - The capacity scheduler was developed by Yahoo. Several features of Fair scheduler are included in Capacity Scheduler.
a) Jobs are submitted into queues.
b) Queues are allocated a fraction of the total resource capacity.
c) Free resources are allocated to queues beyond their total capacity.
d)Within a queue a job with a high level of priority has access to the queue's resources.
There is no preemption once a job is running.
--------------------X-------------X-----------X------------X---------------------
:) I know that few terms like preemption , jobs, FIFO ,Scheduling may sound a bit strange to you but don't worry at all I will Include it In my next post.
In version 0.19 job scheduler was re factored out of Job Tracker and other alternative scheduler were used in place of it .
1. Fair Scheduler - The fair scheduler was developed by Facebook with a main aim to provide fast response times for small jobs and QoS(Quality Of Service) for production jobs.
The fair scheduler has three key features:
a) Jobs are grouped into pools.
b) Each pool is assigned a guaranteed minimum share.
c) Excess capacity is split between jobs.
By default, jobs that are uncategorized go into a default pool.
2. Capacity scheduler - The capacity scheduler was developed by Yahoo. Several features of Fair scheduler are included in Capacity Scheduler.
a) Jobs are submitted into queues.
b) Queues are allocated a fraction of the total resource capacity.
c) Free resources are allocated to queues beyond their total capacity.
d)Within a queue a job with a high level of priority has access to the queue's resources.
There is no preemption once a job is running.
--------------------X-------------X-----------X------------X---------------------
:) I know that few terms like preemption , jobs, FIFO ,Scheduling may sound a bit strange to you but don't worry at all I will Include it In my next post.