Question

A SysOps administrator deploys an EC2 instance via AWS CloudFormation. A UserData script installs and configures a large application that takes several minutes to finish. The team notices that CloudFormation reports CREATE_COMPLETE for the instance almost immediately, before the application is actually ready, causing dependent resources to fail. What is the correct way to ensure CloudFormation waits until the application setup completes before marking the resource successful?

Accepted Answer

Add a CreationPolicy to the EC2 resource and call cfn-signal from the UserData script after the application setup finishes.

Answer

Add a DependsOn attribute to the EC2 resource referencing the application configuration.

Answer

Increase the stack's timeout value in the CloudFormation console so the create operation waits longer.

Answer

Attach a DeletionPolicy of Retain so the instance is not recreated during provisioning.