Building a new ECS container instance AMI
To test our life cycle management solution, we need to have a mechanism to force your ECS container instances to be terminated. Although you could simply adjust the desired count of your Auto Scaling group (which actually is a common scenario when your Auto Scaling groups are scaling down), another common scenario where this can happen is when you need to update your ECS container instances by introducing a newly built Amazon Machine Image (AMI), complete with the latest operating system and security patches, and up-to-date versions of Docker Engine and the ECS agent. At the very least, if you are building a custom ECS container instance AMI using an approach similar to what you learned in Chapter 6, you should be rebuilding your AMI each time Amazon releases a new version of the base ECS-optimized AMI, and it is common practice to update your AMIs on a weekly or monthly basis.
To simulate introducing a new AMI into your ECS cluster, you can simply...