问题：azkban Cannot request memory (Xms 0 kb, Xmx 0 kb) from system for job command, sleep for 60 secs and retry, attempt 4 of 720
原因：azkaban默认需要3G的内存，剩余内存不足则会报异常。
解决办法：修改azkaban-solo-server/build/distributions/azkaban-solo-server-0.1.0-SNAPSHOT/plugins/jobtypes下的commonprivate.properties
添加:memCheck.enabled=false
