Bug 1041155

Summary: [RFE][nova]: Reload Configuration without service restart
Product: Red Hat OpenStack Reporter: RHOS Integration <rhos-integ>
Component: RFEsAssignee: RHOS Maint <rhos-maint>
Status: CLOSED UPSTREAM QA Contact:
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: unspecifiedCC: markmc, yeylon
Target Milestone: ---Keywords: FutureFeature
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
URL: https://blueprints.launchpad.net/nova/+spec/config-reload-no-restart
Whiteboard: upstream_milestone_none upstream_status_unknown upstream_definition_superseded
Fixed In Version: Doc Type: Enhancement
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2015-03-19 17:04:28 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description RHOS Integration 2013-12-12 13:48:30 UTC 
Cloned from launchpad blueprint https://blueprints.launchpad.net/nova/+spec/config-reload-no-restart.

Description:

Problem: We shouldn't need to restart the service just to reload some simple config options. But we also can't hope to convert all config at once.

Note, we are building on existing support here: https://blueprints.launchpad.net/oslo/+spec/cfg-reload-config-files

Suggested route:
* mark options we can reload without restart with "can_update_without_restart=True", default to false
* add a new param to reload config: without_restart=True
* if True, we only update config values that are marked with can_update_without_restart=True, and log a warning for any other changes that are spotted
* we can then convert a few easy options to can_update_without_restart=True
* other will be able to follow the pattern

We can trigger the reload using a file watcher, using something similar to: https://pypi.python.org/pypi/watchdog

Specification URL (additional information):

None