Comment 2 for bug 1491027

@Matthew, this isn't exactly the same point.

To give more context, we're developing the LMA Infrastructure Alerting plugin [1] that will offer a custom role for deploying the alerting server (eg Nagios server). When the OpenStack environment is modified after the initial deployment (eg when nodes are added or removed), the Nagios configuration needs to be updated otherwise it will trigger alerts for removed nodes or lacks alerting for new nodes. The problem is that there's no way to do it with MOS 7.0 and the update_required parameter doesn't help either.

To workaround the issue, we're planning to have a cron job running on the alerting node that will monitor the nodes.yaml file. When it changes, the job will re-run the necessary Puppet manifests. AFAICT this should work when the environment scales up (the file is correctly propagated then) but not when the environment scales down. Hence this bug being filled. Hope this is clearer.

Eventually, Fuel should be improved to offer this capability out of the box as it has been requested by other plugin's developers [2].

[1] https://github.com/stackforge/fuel-plugin-lma-infrastructure-alerting
[2] https://blueprints.launchpad.net/fuel/+spec/fuel-task-notify-other-nodes