What's the advantages of using Docker with AWS Elastic Beanstalk?

Question

I've deployed a couple of websites on AWS Elastic Beanstalk, and then I heard of Docker, so I think I can probably try it this time for a small business e-commerce website (Lumen + Angularjs). I searched all over the Internet, but as having no experience with the Docker, it is still hard to get a great understanding of the advantages of using Docker on AWS. All I can find are some descriptions like this:

Pros

• Separated management of dependencies and server hardware
• Development environment is identical (internally) to production environment
• Dependency management means that not everyone needs intimate knowledge about every part of your technology stack
• Easy custom task and service scheduling with AWS SDK or a third-party tool
• Make good use of available resources with ECS assigning tasks to EC2’s with enough free resources Use auto-scaling when tasks need more resources

Cons

• Build produces a large file that needs to be uploaded
• Docker NAT can increase network latency (use docker run –net=host, for more docker performance info see here)
• Some developers have fits when the word docker is mentioned
• Some applications need to be fixed to work on Docker

Can someone give me some simple examples or explanations?

Answer 1

I think the primary advantage of Docker on Elastic Beanstalk is the flexibility it gives you when compared to running your app on one of the specific runtime environments Elastic Beanstalk supports.

From the official documentation:

Elastic Beanstalk supports the deployment of web applications from Docker containers. With Docker containers, you can define your own runtime environment. You can choose your own platform, programming language, and any application dependencies (such as package managers or tools), that aren't supported by other platforms. Docker containers are self-contained and include all the configuration information and software your web application requires to run.

For example I've seen lots of people ask how to deploy Java applications that use something other than Tomcat on Elastic Beanstalk. You couldn't do that before they added Docker support.

If you are using one of the officially supported Elastic Beanstalk runtimes then it is difficult for me to recommend using Docker. It would somewhat separate your app from AWS specifics, theoretically allowing you to run your app more easily outside of AWS. If you want to avoid vendor lock-in at all costs, or if you just want to stay up to date on the latest technologies, then Docker is a good choice. Otherwise, if you already have your app running on Elastic Beanstalk there isn't much reason for you to convert it to Docker.

Edit: Note that my reply is related to using Docker specifically with Elastic Beanstalk, as your question title asks. I see in your question that you also refer to the ECS service and the more general use of Docker on AWS. That's a much bigger discussion and there are definitely some advantages to using Docker instead of plain EC2 instances for certain things.

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Edit 10/5/2019: AWS seems to be pushing people towards Docker now so that they don't have to maintain updates to the official runtimes. For example the latest Java runtime for Elastic Beanstalk is Java 8. So if you want to run a modern version of Java on Elastic Beanstalk you would have to use Docker.

Answer 2

There is a certain amount of environments considering the elastic beanstalk. In order to add extra configurations and have something custom upon these environments, you have to utilize .ebextensions.

However ebextensions are being executed on the creation of the elastic beanstalk server. Also .ebextensions are not as easy to implement as a docker image.

By using docker on elastic beanstalk you have your image setup ready to be deployed without any extra configuration, and docker is great when you need an immutable architecture.