Qfyilyi

I have a working container in Amazon's ECS that runs a program as a task. I would like to pass some program arguments, as I would do when running locally with docker run. I have managed to do passing a new entrypoint in the container configuration in ECS, as if I were passing it in the docker run command line.

Unfortunately, when doing so, I am overriding the internal entrypoint that was already defined in the image. I would like to use the internal entrypoint, just adding some more command line arguments, like --debug options. Is there any way to do that?

Thanks in advance.

It was easy: the command line arguments can be passed as Command in ECS configuration, instead of entrypoint.

You can add command line arguments for the container entry point when creating new ECS task revision in AWS console. Open your container settings, and under the ENVIRONMENT label put the comma-separated list of command line arguments into the "Command" field.

Example:

--debug,--packages org.apache.hadoop:hadoop-aws:2.7.3

will add 2 command line arguments to your container entry point.

When you run a task in ECS you can specify container overrides.

In the AWS console this can be found at the bottom in the Advanced Options section.

On the CLI you can pass in a JSON object with the overrides like so:

aws ecs run-task ... --overrides '{"containerOverrides": [{"name": "whatever", "command": ["foo", "bar"}]}'

The command is the CMD that gets executed inside the container.

In the same way environment variables can be passed to a container. Here's the list of possible options as described in the aws-cli docs:

{

  "containerOverrides": [

    {

      "name": "string",

      "command": ["string", ...],

      "environment": [

        {

          "name": "string",

          "value": "string"

        }

        ...

      ],

      "cpu": integer,

      "memory": integer,

      "memoryReservation": integer

    }

    ...

  ],

  "taskRoleArn": "string",

  "executionRoleArn": "string"

}

_{For some reason the name always has to be set in the overrides. ¯_(ツ)_/¯}

Use environment section in ecs task definition to inject your configs.

"environment" : [

    { "name" : "string", "value" : "string" },

    { "name" : "string", "value" : "string" }

]

Please refer to the following aws documentation
http://docs.aws.amazon.com/AmazonECS/latest/developerguide/task_definition_parameters.html#container_definition_environment