ProcessLauncher should support reloading config file for parent process on receiving SIGHUP

[Elena Ezhova]

Currently, when a parent process receives SIGHUP it just sends SIGHUP to its children. While children reload their config files and call reset on their services, parent continues to run with old config.

[Elena Ezhova (eezhova)]

Related patch: https://review.openstack.org/#/c/165104/

[Davanum Srinivas (DIMS) (dims-v)]

Tested against both nova and neutron latest trunk. works well.

[Elena Ezhova (eezhova)]

@Dims, did you test this for ProcessLauncher? Because now only ServiceLauncher is supposed to reload parent config on SIGHUP.

[Elena Ezhova (eezhova)]

I have tested nova-api master too (as well as neutron) the following way:

1. Added logging to nova.service.reset method:

ash@ubuntu:/opt/stack/nova$ git diff
diff --git a/nova/service.py b/nova/service.py
index 3ae307c..5f4e952 100644
--- a/nova/service.py
+++ b/nova/service.py
@@ -366,6 +366,7 @@ class WSGIService(object):
         :returns: None

         """
+ LOG.exception("Calling reset!")
         self.server.reset()

     def _get_manager(self):

2. Changed logging format in nova.conf to show pids

3. Started nova-api in daemon mode with the default number of workers (metadata_workers = 2, ec2_workers = 2, osapi_compute_workers = 2)

4. Verified that all processes are running:

ash@ubuntu:~/devstack$ ps -ef | grep nova-api
ash 11999 9714 0 13:00 pts/10 00:00:04 /usr/bin/python /usr/local/bin/nova-api
ash 12008 11999 0 13:00 pts/10 00:00:00 /usr/bin/python /usr/local/bin/nova-api
ash 12009 11999 0 13:00 pts/10 00:00:00 /usr/bin/python /usr/local/bin/nova-api
ash 12010 11999 0 13:00 pts/10 00:00:00 /usr/bin/python /usr/local/bin/nova-api
ash 12011 11999 0 13:00 pts/10 00:00:00 /usr/bin/python /usr/local/bin/nova-api
ash 12018 11999 0 13:00 pts/10 00:00:00 /usr/bin/python /usr/local/bin/nova-api
ash 12019 11999 0 13:00 pts/10 00:00:00 /usr/bin/python /usr/local/bin/nova-api
ash 12245 8600 0 13:10 pts/32 00:00:00 grep --color=auto nova-api

5. Sent SIGHUP to the parent process:

ash@ubuntu:~/devstack$ kill -HUP 11999

6. Checked nova-api's logs: http://paste.openstack.org/show/195347/

Please note, that the parent process (pid = 11999) didn't call reset().

The situation is the same for all services that use ProcessLauncher including neutron. Please, correct me, if there is something I'm missing.

[Davanum Srinivas (DIMS) (dims-v)]

Looks like i just tested nova-compute and not nova api for reload of config files...!

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/167470

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/167470
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=31dfcac6105751f6857215c4a89869d5a779a2fd
Submitter: Jenkins
Branch: master

commit 31dfcac6105751f6857215c4a89869d5a779a2fd
Author: Davanum Srinivas <email address hidden>
Date: Tue Mar 24 21:43:38 2015 -0400

    Sync from Oslo-Incubator - reload config files

    Syncing change I132865fc5c3a12baf02f2991fc82701adfc7ed67 from
    oslo-incubator to fix a Nova bug

    Closes-Bug: #1433142
    Change-Id: Ia4077324f23c6cbdaa54c79341992528f6c6d2cd

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/167974

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/167974
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=f92d22d91b8a29a0088c69a1cf4940c822d38847
Submitter: Jenkins
Branch: master

commit f92d22d91b8a29a0088c69a1cf4940c822d38847
Author: Elena Ezhova <email address hidden>
Date: Thu Mar 26 15:33:36 2015 +0300

    Sync service from oslo-incubator

    This sync includes changes that are required to fix handling
    of SIGHUP in Neutron.

    The following changes and bugfixes are included:

    d24b658 Revert "Optimization of waiting subprocesses in ProcessLauncher"
    593005b ProcessLauncher: reload config file in parent process on SIGHUP
    f29e865 Store ProcessLauncher signal handlers on class level
    bf92010 Optimization of waiting subprocesses in ProcessLauncher

    Change-Id: If0aab4e8978422346f6ba4c9e6272cdaf39db6cb
    Closes-Bug: #1433142
    Related-Bug: #1276694

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: neutron-pecan
Review: https://review.openstack.org/185072