CDK ECS Fargate - how to specify arguments to Docker container?

Question

Hi,
Trying to Deploy an ECS service running a single task with the image: `datalust/seq:latest`. I want to specify certain arguments to my container, how do I achieve the equivalent of running the following local command:

```docker run --name seq -e ACCEPT_EULA=Y -p 5341:5341 -p 80:80 datalust/seq:latest```

Using ECS Fargate. My CDK code is below:

```seqTaskDefinition.addContainer('SeqContainer', {
      image: ContainerImage.fromRegistry('datalust/seq:latest'),
      containerName: `SeqContainer`,
      command: [`--name`, `seq`,`-v`, `/efs:/efs`],
      essential: true,
      cpu: 1024,

environment: {
        ACCEPT_EULA: 'Y'
      },
      portMappings: [
        { containerPort: 80, hostPort: 80 },
        { containerPort: 5341, hostPort: 5341 }
      ],
      logging: new AwsLogDriver({
        logGroup: new LogGroup(this, 'SeqLogGroup', {
          logGroupName: '/aws/ecs/SeqLogGroup',
          removalPolicy: RemovalPolicy.DESTROY
        }),
        streamPrefix: 'SeqService'
      })
    })
```

However when I run with this config, it fails to start my task properly, it seems that the `Command` specification overrides the default behaviour of the container, whereas I just want to supply arguments to the container as an addition to the default behaviour.

Answer

The `command` parameter of the task definition is to specify the command to run in your container at startup. The other parameters that you send to the docker cli (i.e. -e, -v, -p) usually map to other parameters of the task definition.

You properly used `environment` for `-e` and `portMappings` for `-p`. For `-v` you need to use `volumes` and `mountPoints` in your Task Definition. You don't need the `--name` parameter, it is specified in `containerName`.

See this link for more information on how to use EFS volumes with ECS: https://docs.aws.amazon.com/AmazonECS/latest/developerguide/efs-volumes.html

See this for full reference of task definition parameters: https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task_definition_parameters.html

CDK ECS Fargate - how to specify arguments to Docker container?

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