On the other day, I had a chance to try ECS (Amazon EC2 Container Service). ECS is a container management service provides by AWS. Though I heard about it and thought it must be useful, there were some points to be cared as usual. This is the note for the ECS users and of course for me.

What we did

I tried to run machine learning algorithm on ECS.

They are the docker image containing machine learning libraries we used. We tried to run the container image on ECS through command line.

ECR Register

ECS uses its own Docker registry called ECR. You need to register your account from local machine in order to push Docker image to ECR.

$ aws ecr get-login --region $AWS_REGION

Run the docker login command that was returned in the previous step. Then build your first image.

$ docker build -t myimage:latest .


$ docker tag myimage:latest $YOUR_ECR_URI/myimage:latest

Then push to ECR.

$ docker push $YOUR_ECR_URI/myimage:latest

ECS Cluster

Then we have to construct ECS cluster. The configuration is simple but there are some points to be noted.

Config Name Note
Cluster Name As you like
EC2 Instance Type As you like
Number of instances As you like
Key pair If you want to login to debug, need to specify
Networking Basically no need to do manual configuration
Container instance IAM role Create IAM role which has AmazonEC2ContainerServiceforEC2Role in advance. If you want to keep debug logs please also attach CloudWatchLogsFullAccess.

Create task definition

Containers are run as task on ECS. Tasks are created by task definition.

Task Definition Config Note
Task Definition Name As you like
Task Role Need to create role attached proper policy for doing your desired tasks. For example, if a container needs to access S3, it is necessary to give AmazonS3FullAccess policy.
Network Mode Bridge is enough
Container definition As you like. But one thing to be noted is entry point definition. It should be written in comma separated format. (e.g. python,script.py,arg1,arg2). So we cannot use the arguments including comma!
Log Configuration If you created Log Group in CloudWatch, your task can send stdout to CloudWatch. Please set awslogs for log driver and corresponding configurations. (e.g. awslogs-group, awslogs-region are required)

Run task

There are two ways to run task on ECS.

  • Run task from AWS console.

AWS Console

Click task definition -> Run Task

Run Task

You can override role, command arguments and environment variables etc.


$ aws ecs run-task \
    --cluster=$YOUR_CLUSTER_NAME \
    --task-definition=$TASK_NAME:$TASK_REVISION \
    --overrides '{"containerOverrides":[{"name":$CONTAINER_NAME,"command":["python","script.py","arg1","arg2"]}]}'

If you will integrate ECS with other system or workflow, AWS CLI is appropriate way.