Details
Major Description
When running with docker on large clusters, we have noticed that sometimes docker containers are not removed - they remain in the exited state, and the corresponding container-executor is no longer running. Upon investigation, we noticed that this always seemed to happen after a nodemanager restart. The sequence leading to the stranded docker containers is:
- Nodemanager restarts
- Containers are recovered and then run for a while
- Containers are killed for some (legitimate) reason
- Container-executor exits without removing the docker container.
After reproducing this on a test cluster, we found that the container-executor was exiting due to a SIGPIPE.
What is happening is that the shell command executor that is used to start container-executor has threads reading from c-e's stdout and stderr. When the NM is restarted, these threads are killed. Then when the container-executor continues executing after the container exits with error, it tries to write to stderr (ERRORFILE) and gets a SIGPIPE. Since SIGPIPE is not handled, this crashes the container-executor before it can actually remove the docker container.
We ran into this in branch 2.8. The way docker containers are removed has been completely redesigned in trunk, so I don't think it will lead to this exact failure, but after an NM restart, potentially any write to stderr or stdout in the container-executor could cause it to crash.