Amazon Web Services have released a series of updates for the Amazon EC2 Container Service (ECS) that include an ECS command line interface, Docker Compose support, task definitions that allow additional Docker configuration options, and an ECS scheduler update that adds support for availability zone awareness. An announcement of the launch of an Amazon EC2 Container Registry (Amazon ECR) has also been made, and this service will launch later in the year.
The new Amazon ECS Command Line Interface (ECS CLI) is a command line interface for Amazon EC2 Container Service (ECS) that provides high level commands, such as the programmatic creation, updating and monitoring of clusters and tasks from a local development environment (‘ecs-cli up’, ‘ecs-cli scale’ and ‘ecs-cli ps’ respectively). The Amazon ECS CLI also now supports Docker Compose (via ‘ecs-cli compose’), a popular open-source tool for defining and running multi-container applications. This allows developers to create and test Docker Compose-defined environments locally, and then push this definition to ECS for execution in a production environment.
The ECS CLI can be downloaded by following the instructions on the Amazon ECS Developer Guide. According to the project’s GitHub issues page, there are several minor functionality issues outstanding, such as the absence of JSON array support, a problem with volume mounting if no ‘hostPath’ is defined, and no support for private Docker registry authentication.
The AWS Compute Blog states that Amazon ECS task definitions, the programmatic description of an application that specifies how containers are scheduled together on an EC2 instance, now support several additional Docker options including Docker labels, working directory, networking disabled, privileged execution, read-only root file system, DNS servers, DNS search domains, ulimits, log configuration, extra hosts (hosts to add to /etc/hosts), and security options for Multilevel Security (MLS) systems such as SELinux.
The Amazon ECS service scheduler that enables the scheduling of task definitions, for example to execute long-running (micro)service applications, has also been updated to include ‘availability zone awareness’. This new feature ensures that as new tasks are launched into an ECS cluster, they will be balanced across AWS availability zones (‘AZs’), which may improve application-level fault-tolerance, for example, by mitigating the risk of all identical instances of a tasks simultaneously failing due to a single AZ failure.
Amazon have also announced that they will release an Amazon EC2 Container Registry (Amazon ECR) later in the year. The Amazon Compute blog states that a container registry is often a critical component of any production deployment of a Docker-based ecosystem, as this is where container images are stored by a continuously delivery build pipeline (or local Docker tooling) and retrieved by a Docker clustering/scheduling runtime, such as Amazon ECS, Docker Swarm, or Kubernetes.
Although operators can currently host their own Docker registry on Amazon ECS (or use a commercial offering, such as Docker Enterprise Hub or CoreOS’s Quay.io), Amazon have stated that the ECR service will store images durably within S3, provide encryption for images at rest and in transit, and integrate with AWS Identity and Access Management (IAM) to simplify authorisation and provide fine-grained control. Amazon have stated that they working with multiple continuous delivery-focused launch partners including Shippable, CloudBees, CodeShip, and Wercker to provide integration with Amazon ECS and Amazon ECR, with a focus on automatically building and deploying Docker images.
Additional information on the Amazon ECS updates can be found on the AWS Official blog, and a series of Amazon ECS-related videos from the recent AWS re:Invent conference, held in Las Vegas, USA, can be found on the AWS Compute Blog.