[HADOOP-8353] hadoop-daemon.sh and yarn-daemon.sh can be misleading on stop

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.23.1
• Fix Version/s: 2.0.0-alpha
• Component/s: scripts
• Target Version/s: 2.0.0-alpha
• Hadoop Flags: Reviewed
• Assignee: Roman Shaposhnik
• Reporter: Roman Shaposhnik
• Created: 03/May/12 16:53
• Updated: 06/Aug/12 20:46
• Resolved: 11/May/12 16:18

Description

The way that stop actions is implemented is a simple SIGTERM sent to the JVM. There's a time delay between when the action is called and when the process actually exists. This can be misleading to the callers of the *-daemon.sh scripts since they expect stop action to return when process is actually stopped.

I suggest we augment the stop action with a time-delay check for the process status and a SIGKILL once the delay has expired.

I understand that sending SIGKILL is a measure of last resort and is generally frowned upon among init.d script writers, but the excuse we have for Hadoop is that it is engineered to be a fault tolerant system and thus there's not danger of putting system into an incontinent state by a violent SIGKILL. Of course, the time delay will be long enough to make SIGKILL event a rare condition.

Finally, there's always an option of an exponential back-off type of solution if we decide that SIGKILL timeout is short.

Issue Links

• incorporates: HADOOP-8656 backport forced daemon shutdown of HADOOP-8353 into branch-1
• is related to: HADOOP-8650 /bin/hadoop-daemon.sh to add "-f <timeout>" arg for forced shutdowns