[openstack-dev] [Heat] as-update-policy implementation details

Zane Bitter zbitter at redhat.com
Thu Aug 8 10:46:10 UTC 2013

On 08/08/13 06:59, Chan, Winson C wrote:
> Proposal for the implementation is documented at https://wiki.openstack.org/wiki/Heat/Blueprints/as-update-policy.  Please review and provide feedback.

Looks pretty good to me. I think there's a simpler way to trigger 
updates to the instances based on changes to the launch config though. 
Because we don't have a real autoscaling API and the launch config does 
not represent any actual physical resource, it just returns its 
(logical) name as the Ref value (that's why renaming it is the only way 
to trigger an update at the moment). It ought to be returning the 
_physical_ resource name, which is (now) unique for each incarnation. So 
if you change something in the launch config that causes it to be 
replaced during update, it will get a new Ref id, and that will trigger 
updates to the autoscaling group also.

Other resource types shouldn't need this, because for the most part they 
are returning the uuid of the underlying resource. The exception are the 
ones where there is no underlying resource (i.e. resource_id is None).

So the "Modify LaunchConfiguration class" section can be changed to just 
"Return self.physical_resource_name() from FnGetRefId().", and the 
"Modify StackUpdate class" and "Modify Resource class" sections can be 
removed. The rest looks good.


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