Understand CloudFormation stack creation events - AWS CloudFormation

Understand CloudFormation stack creation events

During stack deployment, several events occur to create, configure, and validate the resources defined in the stack template. Understanding these events can help you optimize your stack creation process and streamline deployments.

  • Resource creation events – When each resource starts the creation process, a Status of CREATE_IN_PROGRESS event is set. This event indicates that the resource is being provisioned.

  • Eventual consistency check – A significant portion of the stack creation time is spent performing an eventual consistency check against the resources created by the stack. During this phase, the service performs internal consistency checks, ensuring the resource is fully operational and meets service stabilization criteria defined by each AWS service.

  • Configuration complete event – When each resource has finished the eventual consistency check phase of the provisioning, a Detailed status of CONFIGURATION_COMPLETE event is set.

  • Resource creation complete event – After the resource has been created and configured as specified, and the configuration matches what is specified in the template, the Status of CREATE_COMPLETE event is set.

You can leverage the CONFIGURATION_COMPLETE event to streamline your stack creation process in scenarios where resource eventual consistency check is not required, such as validating a pre-production stack configuration or cross-stack provisioning. You can use this event in multiple ways. For example, you can use it as a visual signal to skip waiting for the resource or stack consistency check to finish. Or you could use it to create an automated mechanism using continuous integration and continuous delivery (CI/CD) to trigger additional actions.

Important

While leveraging the CONFIGURATION_COMPLETE event accelerates stack creation times, you should be aware of its trade-offs. First, it's only supported for a subset of resource type that support drift detection. For a list of resource types that support drift detection, see Resource type support. This approach may not be suitable for all scenarios, especially where resources require thorough eventual consistency checks to ensure full operational readiness across the cloud environment (for example, in production environments). We recommend carefully assessing your deployment requirements and the criticality of the consistency checks for each resource. Use the CONFIGURATION_COMPLETE event to optimize deployment speeds without compromising the integrity and reliability of your infrastructure.

Because the CONFIGURATION_COMPLETE event is not guaranteed to be set, any scenarios that use it should be prepared to handle a CREATE_COMPLETE event when no CONFIGURATION_COMPLETE event was set.

Diagram showing the sequence of events for resource creation and eventual consistency check in a stack.

When the stack deployment starts, both the AWS::ECR::Repository and AWS::ECS::Cluster resources start the creation process (ResourceStatus = CREATE_IN_PROGRESS. When the AWS::ECR::Repository resource type has started the eventual consistency check (DetailedStatus = CONFIGURATION_COMPLETE), then the AWS::ECS::TaskDefinition resource can start the creation process. Similarly, once the AWS::ECS::TaskDefinition resource begins the eventual consistency check, the AWS::ECS::Service resource start the creation process.

CREATE_IN_PROGRESS and CREATE_COMPLETE events

  • [Stack]: CREATE_IN_PROGRESS

  • [Resource]: ECR Repository CREATE_IN_PROGRESS

  • [Resource]: ECS Cluster CREATE_IN_PROGRESS

  • [Resource]: ECR Repository CREATE_IN_PROGRESS, CONFIGURATION_COMPLETE

  • [Resource]: ECS Task Definition CREATE_IN_PROGRESS

  • [Resource]: ECS Cluster CREATE_IN_PROGRESS, CONFIGURATION_COMPLETE

  • [Resource]: ECS Task Definition CREATE_IN_PROGRESS, CONFIGURATION_COMPLETE

  • [Resource]: ECS Service CREATE_IN_PROGRESS

  • [Resource]: ECR Repository CREATE_COMPLETE

  • [Resource]: ECS Cluster CREATE_COMPLETE

  • [Resource]: ECS Service CREATE_IN_PROGRESS, CONFIGURATION_COMPLETE

  • [Stack]: CREATE_IN_PROGRESS, CONFIGURATION_COMPLETE

  • [Resource]: ECS Task Definition CREATE_COMPLETE

  • [Resource]: ECS Service CREATE_COMPLETE

  • [Stack]: CREATE_COMPLETE