Port exposed from Docker image not mapped to Elastic Beanstalk host

Question

I created an AWS Elastic Beanstalk environment with a Load Balancer configured on ports 80 and 8080, I also turned off proxy (was Nginx initially). I created simple Node.js app and Dockerfile for it. Also I added file Dockerrun.aws.json with content:

{
  "AWSEBDockerrunVersion": "1",
  "Ports": [
    {
      "HostPort": "8080",
      "ContainerPort": "8080"
    }
  ]
}

I have my own image, not published anywhere so I didn't mentioned the Image section. After deployment I see one Docker container running with a single port 8080 opened (as expected). But the Elastic Beanstalk system doesn't forward this port to internal IP address.

What am I doing wrong and how to instruct Elastic Beanstalk to forward port from container to host (I know how to do it manually but it is not the case for Elastic Beanstalk) ?

Answer 1

I had the same problem in a rails container (port 3000 using puma) by default rails server only binds localhost to the listening interface, I had to use -b option to bind 0.0.0.0 and that solved the problem.

In react I have no the same problem cause npm serve package binds all interfaces by default

Answer 2

I had a very similar issue:

• A single Docker container with port 8080 exposed;
• Proxy set to none (nginx disabled);
• Dockerrun.aws.json similar to the one in the question, but using a pre-built image instead of a Dockerfile;
• Application Load Balancer (ALB) configured with the default process that routes requests to port 8080 on the servers.

In this configuration, the application container started on the server, but Elastic Beanstalk didn't map port 8080 of the port to the port of the container. It worked if I mapped the port manually, starting another container using the same image. There were no error messages in the logs, and nothing in documentation explained what the problem can be.

Changing the ALB configuration to use port 80 instead of 8080 for the process resolved this issue.