aws-ecs-fargate-action

How to setup a CD for AWS ECS with Fargate

Docker

First, create an application that has a buildable Docker image.

Resources

Then, create

• an Elastic Container Registry to store your Docker images, save its name for later. Remember to allow tag mutability, such that the latest tag can be updated.
• an Elastic Container Service cluster to run your containers
• an ECS task definition, which specifies which containers should run, which ports to open, how much resources, etc. Remember to use the latest tag for your image, so that you don't need to update the task definition when there is a container update.
• an ECS service, which will run your task definition.
  • You'll see that there are "services" and "tasks". Services will guarantee that your task will always stay up, while tasks should be used for one-off jobs, since they will not restart when the containers stop or fail. Therefore, we will use a Service here.

IAM user

Create an IAM user with a policy that is able to push and tag new images to your ECR repository (it's best to allow pushes/tags to only a specific repository, and not all repositories of your account), and that is also able to update your ECS service. Create an access key with a secret, and store both in GitHub secrets:

• AWS_ACCESS_KEY_ID
• AWS_SECRET_ACCESS_KEY
  Also, store in an AWS_REGION GitHub secret your AWS region.

Workflow

The workflow in this repository will run whenever a tag specifying a release-number regex (like "0.4.3") is pushed. Then, it will

• Build the docker image as latest
• Tag latest with the current version (eg "0.4.3")
• Push both of them to the ECR registry (creating a new version in the repo, and pointing latest to the current version).
• Force update the service. Since the task definition wont't change (as it uses the latest tag, remember?), we need to restart the service, such that it stops the current tasks and creates new ones, therefore using the current latest tag.

Make it better

Next steps:

• Make CI run only when source files change (and not the README for example)
• Make CD run only when CI runs successfully
• Createa a GitHub release when CD runs