Hi Adrian, On Mon, Mar 9, 2015 at 6:53 PM, Adrian Otto <[email protected]> wrote:
> Magnum Team, > > In the following review, we have the start of a discussion about how to > tackle bay status: > > https://review.openstack.org/159546 > > I think a key issue here is that we are not subscribing to an event feed > from Heat to tell us about each state transition, so we have a low degree > of confidence that our state will match the actual state of the stack in > real-time. At best, we have an eventually consistent state for Bay > following a bay creation. > > Here are some options for us to consider to solve this: > > 1) Propose enhancements to Heat (or learn about existing features) to emit > a set of notifications upon state changes to stack resources so the state > can be mirrored in the Bay resource. > A drawback of this option is that it increases the difficulty of trouble-shooting. In my experience of using Heat (SoftwareDeployments in particular), Ironic and Trove, one of the most frequent errors I encountered is that the provisioning resources stayed in deploying state (never went to completed). The reason is that they were waiting a callback signal from the provisioning resource to indicate its completion, but the callback signal was blocked due to various reasons (e.g. incorrect firewall rules, incorrect configs, etc.). Troubling-shooting such problem is generally harder. > > 2) Spawn a task to poll the Heat stack resource for state changes, and > express them in the Bay status, and allow that task to exit once the stack > reaches its terminal (completed) state. > > 3) Don’t store any state in the Bay object, and simply query the heat > stack for status as needed. > Are each of these options viable? Are there other options to consider? > What are the pro/con arguments for each? > > Thanks, > > Adrian > > > > __________________________________________________________________________ > OpenStack Development Mailing List (not for usage questions) > Unsubscribe: [email protected]?subject:unsubscribe > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >
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