Stale pid files exist after metadata namespace proxy is terminated

[Darragh O'Reilly]

These pid files are not removed when shutdown sents SIGTERM.

$ ps -ef | grep metadata-proxy
root 17725 1 0 07:05 ? 00:00:00 /usr/bin/python /usr/local/bin/neutron-ns-metadata-proxy --pid_file=/opt/stack/data/neutron/external/pids/a1752c3b-cf08-4155-a268-e97ca5320221.pid --metadata_proxy_socket=/opt/stack/data/neutron/metadata_proxy --router_id=a1752c3b-cf08-4155-a268-e97ca5320221 --state_path=/opt/stack/data/neutron --metadata_port=9697 --debug --verbose

$ ls -l /opt/stack/data/neutron/external/pids/a1752c3b-cf08-4155-a268-e97ca5320221.pid
-rwxr-xr-x 1 root root 5 Sep 10 07:05 /opt/stack/data/neutron/external/pids/a1752c3b-cf08-4155-a268-e97ca5320221.pid

$ sudo kill 17725

$ ls -l /opt/stack/data/neutron/external/pids/a1752c3b-cf08-4155-a268-e97ca5320221.pid
-rwxr-xr-x 1 root root 5 Sep 10 07:05 /opt/stack/data/neutron/external/pids/a1752c3b-cf08-4155-a268-e97ca5320221.pid

In daemon.py delete_pid() is registerd with atexit.register() to remove the pid file when the process exits. https://github.com/openstack/neutron/blob/2013.2.b3/neutron/agent/linux/daemon.py#L125

But the atexit man page says: "Functions registered using atexit() (and on_exit(3)) are not called if a process terminates abnormally because of the delivery of a signal."

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/45831

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/45831
Committed: http://github.com/openstack/neutron/commit/4535505fc1ee6aae49f3b054cffd48b88f062e31
Submitter: Jenkins
Branch: master

commit 4535505fc1ee6aae49f3b054cffd48b88f062e31
Author: Darragh O'Reilly <email address hidden>
Date: Tue Sep 10 09:06:28 2013 +0000

    Ensure pid file is removed when metadata ns daemon receives SIGTERM

    These files from the metadata namespace proxy are not being removed
    because delete_pid() is registered with atexit. This means it only runs
    when a process exits normally and won't run when a process receives a
    signal.

    This patch registers a signal handler for SIGTERM that calls exit()
    to make the process exit normally so delete_pid() gets called.

    Fixes bug: 1223250

    Change-Id: I6309802e2109359560ccc084559ec8e4d310cce2