On Mon, Jul 31, 2017 at 10:01 AM, Adam Spiers <aspi...@suse.com> wrote:
> Hi all, > > I recently discovered a bug where barbican-worker would hang on > shutdown if queue.asynchronous_workers was changed from 1 to 2: > > https://bugs.launchpad.net/barbican/+bug/1705543 > > resulting in a warning like this: > > WARNING oslo_messaging.server [-] Possible hang: stop is waiting for > start to complete > > I found a similar bug in Sahara: > > https://bugs.launchpad.net/sahara/+bug/1546119 > > where the fix was to call start() on the RPC service before making the > launcher wait() on it, so I ported the fix to Barbican, and it seems > to work fine: > > https://review.openstack.org/#/c/485755 > > I noticed that both projects use ProcessLauncher; barbican uses > oslo_service.service.launch() which has: > > if workers is None or workers == 1: > launcher = ServiceLauncher(conf, restart_method=restart_method) > else: > launcher = ProcessLauncher(conf, restart_method=restart_method) > > However, I'm not an expert in oslo.service or oslo.messaging, and one > of Barbican's core reviewers (thanks Kaitlin!) noted that not many > other projects start the task before calling wait() on the launcher, > so I thought I'd check here whether that is the correct fix, or > whether there's something else odd going on. > > Any oslo gurus able to shed light on this? > > Thanks! > Adam > > __________________________________________________________________________ > OpenStack Development Mailing List (not for usage questions) > Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > As far as an oslo.messaging server is concerned, the order of operations is: server.start() # do stuff until ready to stop the server... server.stop() server.wait() The final wait blocks until all requests that are in progress when stop() is called finish and cleanup. -K -- Ken Giusti (kgiu...@gmail.com)
__________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
