Cloned from launchpad blueprint https://blueprints.launchpad.net/heat/+spec/auto-scaling-notifications.

Description:

Enabling of stack's life-cycles management with auto-scaling requires some form user-land notifications to be inform of scale-up and scale-down events. Upon the receiving of such notifications, a Heat client could initiate a (re)configuration action to take into account that change of state. For example, add or remove the IP address of a cluster of instances and so reflect the actual state of the stack. The creation of an auto-scaling-group in AWS EC2 supports that capability through specifying a NotificationConfiguration property which associates an SNS topic with a list of auto-scaling events. 
Check http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-as-notificationconfiguration.html for details. Similarly, it is assumed that user-land notifications could be supported in Heat for auto-scaling using Marconi, the OpenStack Queuing and Notification Service for the following event types:

- autoscaling:EC2_INSTANCE_LAUNCH
- autoscaling:EC2_INSTANCE_LAUNCH_ERROR
- autoscaling:EC2_INSTANCE_TERMINATE
- autoscaling:EC2_INSTANCE_TERMINATE_ERROR

Specification URL (additional information):

None