Amazon created its ECS (EC2 Container Service) system for launching Docker containers directly in EC2 for two reasons. First, to bring a new feature to its user base, but also to take on competitors like Google's Container Engine.
That dynamic hasn't changed much. Since the initial release, Amazon has ushered forth a new wave of ECS features focused on deployment, management, and configuration. The upgrades result from demands by Amazon's users -- and possibly pressure from third-party container management offerings that run on AWS.
As revealed in both a blog post and the Thursday Amazon Re:Invent event keynote, the first of the new ECS services -- the Amazon ECR (EC2 Container Registry) -- seems almost redundant. Like the Docker Hub, ECR stores Docker images for reuse. Images can be pushed from your development system to ECR, then to ECS for deployment. Amazon is also lining up name-brand container outfits like Shippable, CloudBees, CodeShip, and Wercker to provide ECS support when the service launches later this year.
Why use ECR, if it looks, sounds, and even smells like Docker Hub? Two reasons: One, by using Amazon's infrastructure, containers stored in ECR can be made available across multiple AWS regions. Second, ECR integrates with AWS Identity and Access Management tools, allowing users to enforce fine-grained controls over containers (who gets to run what and how). With the latter, Amazon is trying to stay abreast of Google, which has a Google Container Registry with many similar features.
Amazon has also added a CLI for managing the container service. The company claims it was due to user feedback, but given that Docker and its cousins all used a CLI from the get-go, this seems more like playing catch-up. Amazon has wisely made the ECS CLI work nicely with at least one existing Docker ecosystem component: Docker Compose. The CLI is also open source, opening the door for Docker hackers to further strut their stuff.
A third addition to ECS -- a change to the service scheduler -- now allows the system to balance scheduled container tasks across AWA availability zones.
Amazon's most obvious competition for ECS comes from other cloud services, but third parties providing commercial container service solutions are a factor as well. Several outfits announced products earlier this week, such as CoreOS and its AWS installer for its Tectonic container stack. Not everyone is likely to opt to use Tectonic over containers directly on AWS, but the success of those solutions will hint at the future directions Amazon will have to push ECS to keep it competitive.