CODEWITHSUNDEEP
amazon-web-servicesdockeramazon-ec2web-applicationsport
Makoto Miyazaki
Makoto Miyazaki

Reputation: 1993

Cannot access a docker webapp on EC2 from a web browser

I am running a webapp in a docker container on Amazon EC2, but my web browser doesn't show anything and it fails to access. Did I forget anything? I would appreciate it if anybody could point out the cause and provide me with the hint.

This is how I run a webapp:

ubuntu@ip-172-31-29-212:~$ sudo docker run  -p5000:5000 makotodocker/my-image:test-0.0.2
 * Serving Flask app 'application.py' (lazy loading)
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: off
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

And here is my Security group settings on this EC2 instance. enter image description here

The public IPv4 address of my instance is 13.38.1.129, so I typed https://13.38.1.129:5000. However the browser doesn't show anything and it just fails to connect.

enter image description here

EDIT: Here is the result of docker ps --all

CONTAINER ID   IMAGE                              COMMAND                  CREATED          STATUS                         PORTS                                       NAMES
695a6671ebf4   makotodocker/my-image:test-0.0.2   "flask run"              20 seconds ago   Up 19 seconds                  0.0.0.0:5000->5000/tcp, :::5000->5000/tcp   angry_taussig

And here is the result of ps -ef | grep 5000, not sure if this helps.

ubuntu@ip-172-31-29-212:~$ ps -ef | grep 5000
root        3784     567  0 05:09 ?        00:00:00 /usr/bin/docker-proxy -proto tcp -host-ip 0.0.0.0 -host-port 5000 -container-ip 172.17.0.2 -container-port 5000
root        3789     567  0 05:09 ?        00:00:00 /usr/bin/docker-proxy -proto tcp -host-ip :: -host-port 5000 -container-ip 172.17.0.2 -container-port 5000
ubuntu      3856    3667  0 05:09 pts/0    00:00:00 grep --color=auto 5000

Upvotes: 0

Views: 2799

Answers (1)

Luis Da Silva
Luis Da Silva

Reputation: 353

You're running your app in your localhost address (127.0.0.1), run it using 0.0.0.0 as host and it should work.

The difference between localhost and 0.0.0.0 is that the former is a loopback address, while the latter is a meta-address that maps all addresses from your instance.

Working example: app.py

from flask import Flask

app = Flask(__name__)

@app.route("/")
def main():
    return "Hello, World!"

Run with:

flask run --host 0.0.0.0

Make sure the port 5000 is whitelisted in the instance's security group.

Upvotes: 2

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