Steve Loughran created HADOOP-9086:
--------------------------------------
Summary: Enforce process singleton rules through an exclusive
write lock on a file, not a pid file +kill -0,
Key: HADOOP-9086
URL: https://issues.apache.org/jira/browse/HADOOP-9086
Project: Hadoop Common
Issue Type: Improvement
Components: util
Affects Versions: 1.1.1, 2.0.3-alpha
Environment: Unix/Linux.
Reporter: Steve Loughran
the {{hadoop-daemon.sh}} script (and other liveness monitors) probe the
existence of a daemon service by a {{kill -0}} of a process id picked up from a
pid file.
This is flawed
# pid file locations may change with installations.
# Linux and Unix recycle pids, leading to false positives -the scripts think
the process is running, when another process is.
# doesn't work on windows.
Having the processes acquire an exclusive write-lock on a known file would
delegate lock management and implicitly liveness to the OS itself. when the
process dies, the lock is relased (on Unixes)
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
