message: infra: add documentation on rolling back ecs services
diff: @@ -36,6 +36,22 @@ pushing any new code beforehand. To do so, run this command:
  aws ecs update-service --cluster rust-ecs-prod --service <service-name> --force-new-deployment
  ```
  +## Rolling back a deployment
  +
  +To rollback a bad deployment you can run the [`aws-rollback.py`] script (stored
  +in the simpleinfra repository) with your [AWS credentials][aws-access] present
  +in the shell. The script requires the name of the ECR container image
  +repository as its first and only argument:
  +
  +```
  +./aws-rollback.py <image-repository-name>
  +```
  +
  +The script will show the list of images available in the repository, and asks
  +for the image number to rollback to. Once that's inserted the script will point
  +the `latest` tag to the image you chose, and if an ECS service with the same
  +name as the repository exists that service will be restarted too.
  +
  ## Deploying application changes
  Each application stores its own Docker container in a [ECR repository][ecr] in
  @@ -98,3 +114,4 @@ pushed there will be deployed to the ECS cluster.
  [aws-access]: aws-access.md
  [console-access]: aws-access.md#using-the-aws-console
  [ecr]: https://aws.amazon.com/ecr/
  +[`aws-rollback.py`]: https://github.com/rust-lang/simpleinfra/blob/master/aws-rollback.py
  