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network-programmingdockeramazon-ec2docker-networkdocker-container
Mahshid Zeinaly
Mahshid Zeinaly

Reputation: 3978

How to send requests to a web server running inside a docker container inside an AWS EC2 machine from the outside world?

I have a Python Flask web server running inside a docker container that is running in an AWS EC2 Ubuntu machine. The container is running on a default network setting (docker0). Within the host EC2, I can send requests (Get, Post) to this web server using docker-machine ip (172.x.x.x) and the forwarded ports (3000: 3000) of the host. 

url: http:// 172.x.x.x:3000 / <api address>

How can I send requests (GET, POST) to this web server from the outside world? For example from another web server running in another EC2 machine. Or even from the web using my web browser?

If you have a solution please explain with as many details as you can for me to understand it.

The only way that I can think of is to write a web server on the main EC2 that listens to the requests and forward them to the appropriate docker container webservers?! But that would be too many redundant codes and I would rather just request to the web server running on the container directly!

Upvotes: 2

Views: 1877

Answers (1)

Amin Suzani
Amin Suzani

Reputation: 587

The IP address of the docker is not public. Your EC2 instance usually has a public IP address though. You need an agent listening on a port on your EC2 instance and pass it to your docker/Flask server. Then you would be able to call it from outside using ec2-instance-ip:agent-port.

It's still not a long-term solution as EC2 IPs change when they are stopped. You'd better use a load-balancer or an elastic IP if you want the ip/port to be reliable.

That's right, it makes a lot of redundant code and an extra failure point. That's why it's better to use Amazon's managed docker service (https://aws.amazon.com/ecs/). This way you just launch an EC2 instance which is a docker and has a public IP address. It still allows you to SSH into your EC2 instance and change stuff.

Upvotes: 2

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