Update ECS with a new ECR Docker image via the CLI

So you have an ECS cluster running with an image on ECR. Want to update the image that cluster is running via the CLI? Here’s how you do it:

First build your docker file locally

docker build --pull -t Jenkins/jenkins:lts --no-cache -t our-services/nonprod/jenkins:latest .

Tag your built image for your repo

docker tag our-services/nonprod/jenkins:latest 1234.dkr.ecr.eu-west-1.amazonaws.com/our-services/nonprod/jenkins:latest

Push your updated docker image to ECR

docker push 1234.dkr.ecr.eu-west-1.amazonaws.com/our-services/nonprod/jenkins:latest

If you need to point to a new task definition do so in the UI, or terraform

Update your service to set desired count of instances to 0

aws ecs update-service --cluster our-services-nonprod-ecs --service our-services-nonprod-jenkins --desired-count 0

For the next step, you need to find the ARN of the tasks running in that service with

aws ecs list-tasks --region eu-west-1 --cluster our-services-nonprod-ecs --service our-services-nonprod-jenkins

This should produce a list of ARNs similar to this:

"taskArns": [
        "arn:aws:ecs:eu-west-1:1234:task/c15edbfb-4aa6-4934-ad18-9083e048e650"
    ]

Then stop the task, replacing the id below with the one you found from the ‘list-tasks’ command

aws ecs stop-task --cluster our-services-nonprod-ecs --task c15edbfb-4aa6-4934-ad18-9083e048e650 --region eu-west-1

And set the desired count back to 1

aws ecs update-service --cluster our-services-nonprod-ecs --service our-services-nonprod-jenkins --desired-count 1