I know that there are already countless questions in this direction, but unfortunately I was not able to find the right answer yet. If a post already exists, please just share the link here.
I have several gitlab CI / CD pipelines. The first pipeline uses Terraform to build the complete infrastructure for an ECS cluster based on Fargate. The second / third pipeline creates nightly builds of the frontend and the backend and pushes the Docker Image with the tag "latest" into the ECR of the (staging) AWS account.
What I now want to achieve is that the corresponding ECS tasks are redeloyed so that the latest Docker images are used. I actually thought that there is a way to do this via CloudWatch Events or whatsoever, but I don't find a really good starting point here. A workaround would be to install the AWS CLI in the CI / CD pipeline and then do a service update with "force new deployment". But that doesn't seem very elegant to me. Is there any better way here?
Conditions:
Thanks a lot!
Ok, for everybody who is interested in an answer. I solved it that way: I execute the following AWS CLI command in the CICD pipeline
aws ecs update-service --cluster <<cluster-name>> --service <<service-name>> --force-new-deployment --region <<region>>
Not the solution I was looking for but it works.
As a general comment it is not recommended to always push the same container tag because then rolling back to a previous version in case of failure becomes really difficult.
One suitable option would be to use git tags.
Let's say you are deploying version v0.0.1
You can create a file app-version.tf which will contain the variable backend-version = v0.0.1 that you can reference on the task definition of the ecs service.
Same thing can be done for the container creation using git describe.
So, you get a new task definition for every git tag and the possibility of rolling back just by changing a value in the terraform configuration.
It is beneficial to refer to images using either digests or unique immutable tags. After the pipeline pushes the image, it could:
As sgramo93 mentions, the big benefit is that rolling back your application can be done by deploying an older revision of the task definition.