[YARN-8632] Threads in SLS quit without logging exception

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.2.0
• Component/s: scheduler-load-simulator
• Hadoop Flags: Reviewed
• Assignee: Xianghao Lu
• Reporter: Xianghao Lu
• Created: 07/Aug/18 12:10
• Updated: 24/Aug/18 18:52
• Resolved: 24/Aug/18 18:26

Description

Recently, I have been using SchedulerLoadSimulator to validate the impact of changes on my FairScheduler. I encountered some problems.
Firstly, I fix a npe bug with the patch in https://issues.apache.org/jira/browse/YARN-4302
Secondly, everything seems to be ok, but I just get "[]" in file realtimetrack.json. Finally, I find the MetricsLogRunnable thread will exit because of npe,
the reason is "wrapper.getQueueSet()" is still null when executing "String metrics = web.generateRealTimeTrackingMetrics();"
So, we should put "String metrics = web.generateRealTimeTrackingMetrics();" in try section to avoid MetricsLogRunnable thread exit with unexpected exception.
My hadoop version is 2.7.2, it seems that hadoop trunk branch also has the second problem and I have made a patch to solve it.

Issue Links

• is duplicated by: YARN-7964 Yarn Scheduler Load Simulator (SLS): MetricsLogRunnable stops working when there are too many jobs needed to load from sls