https://www.quora.com/On-what-basis-do-I-decide-between-Fair-and-Capacity-Scheduler-in-YARN
YARN的缺省调度器，Hortonworks和Apache版本的选择是Capacity Scheduler，Cloudera和MarR选择是Fare Scheduler。
Capacity Scheduler被诟病代码质量不高，bug很多。而Fare Scheduler已经实现了所有Capacity Scheduler的功能，因此建议使用Fare Scheduler。Cloudera在现在版本中建议使用Fare Scheduler，并会在CDH6.0以后将Capacity Scheduler删除。（参见https://www.cloudera.com/documentation/enterprise/release-notes/topics/rg\_deprecated.html）
http://blog.cloudera.com/blog/2016/01/untangling-apache-hadoop-yarn-part-3/
https://blog.cloudera.com/blog/2008/11/job-scheduling-in-hadoop/