[YARN-499] On container failure, include logs in diagnostics

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 2.0.3-alpha
• Component/s: nodemanager
• Assignee: Sandy Ryza
• Reporter: Sandy Ryza
• Created: 22/Mar/13 03:11
• Updated: 12/May/13 19:46
• Resolved: 12/May/13 19:45

Description

When a container fails, the only way to diagnose it is to look at the logs. ContainerStatuses include a diagnostic string that is reported back to the resource manager by the node manager.

Currently in MR2 I believe whatever is sent to the task's standard out is added to the diagnostics string, but for MR standard out is redirected to a file called stdout. In MR1, this string was populated with the last few lines of the task's stdout file, and got printed to the console, allowing for easy debugging.

Handling this would help to soothe the infuriating problem of an AM dying for a mysterious reason before setting a tracking URL (MAPREDUCE-3688).

This could be done in one of two ways.

• Use tee to send MR's standard out to both the stdout file and standard out. This requires modifying ShellCmdExecutor to roll what it reads in, as we wouldn't want to be storing the entire task log in NM memory.
• Read the task's log files. This would require standardizing or making the container log files configurable. Right now the log files are determined in userland and all that is YARN is aware of the log directory.

Does this present any issues I'm not considering? If so it this might only be needed for AMs?

Issue Links

• is related to: MAPREDUCE-3688 Need better Error message if AM is killed/throws exception
• is related to: MAPREDUCE-4362 If possible, we should get back the feature of propagating task logs back to JobClient