Summary

In this chapter, you were introduced to the ECS architecture and learned about the core components that make up ECS. You learned how ECS clusters are a collection of ECS container instances, which run the Docker Engine atop EC2 autoscaling group instances. AWS provide you with a pre-built ECS-optimized AMI, making it very easy to get up and running quickly with ECS. Each ECS container instance includes an ECS agent, which runs as a system container and communicates with ECS, providing the management and control plane required to start, stop, and deploy your containers.

You next created an ECS task definition, which defines a collection of one or more container and volume definitions, including information such as container image, environment variables, and CPU/memory resource allocations. With your ECS cluster and ECS task definition in place, you were then able to create and configure an ECS service, referencing the ECS task definition to define the container configuration for the ECS service, and targeting one or more instances of your ECS service to your ECS cluster.

ECS supports rolling deployments for updates to your container applications, and you were able to successfully deploy a new application change by simply creating a new revision of your ECS task definition and then associating the definition with your ECS service.

Finally, you learned how to use the ECS CLI to simplify the creation of ECS clusters and services, using Docker Compose as a generic mechanism to define task definitions and ECS services.

In the next chapter, you will take a closer look at the Elastic Container Registry (ECR) service, where you will learn how to create your own private ECR repositories and publish your Docker images to these repositories.