When to use a multi-container docker in Elastic Beanstalk for running a Rails App?

Question

I would like to deploy a rails API app to AWS Elastic Beanstalk and noticed that there are two options for docker.

1. Single container
2. Multi-container

I think it is enough with a single container for this app however, I was wondering when is the case to use multi-container. If I would like to deploy two rails apps(one is an API app and the other is an admin app) to a single EC2 instance then is this the case?

Answer 1

Well.. Not really. Multicontainer, as it stays, has more than a one container within overall definition (done with Dockerrun.aws.json file). You can still deploy just one container with whatever application you want, let's say django, Python based framework, where there's an API and admin panel as well and it all sits within one application.

But you may want to deploy your application behind some reverse proxy, it might be Nignx let's say, so there's a need for a second container. That's the case where you would use Multicontainer. The main advantage of using Multicontainer is that each container can talk to each other using local network and some DNS host mapping, so your Nginx container can invoke with proxy_pass any application by its name, like just "backend", where Rails or Django application is living.