問題：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默認需要3G的內存，剩餘內存不足則會報異常。
解決辦法：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