Nginx + Docker Compose - connect() failed (111: Connection refused) while connecting to upstream - docker

Question

thanks for taking the time to read this. I am trying to deploy my application to an AWS EC2 Instance using docker-compose. When i run the command docker-compose up and visit the site, I get an error from nginx saying the below error. I understand that nginx is receiving the request but is unable to find an upstream connection to my react app, and would appreciate any help in correctly configuring the ports/settings.
Error
2 connect() failed (111: Connection refused) while connecting to upstream, client: 108.212.77.70 server: example.com, request: "GET / HTTP/1.1", upstream: "http://172.29.0.4:8003/", host: "example.com"
Here is my nginx default config
upstream meetup_ws {
server channels:8001;
}
upstream meetup_backend {
server backend:8000;
}
upstream meetup_frontend {
server frontend:8003;
}
server {
listen 0.0.0.0:80;
server_name example.com www.example.com;
return 301 https://$server_name$request_uri;
}
server {
listen 443 ssl;
listen [::]:443 ssl;
server_name example.com example.com;
root /var/www/frontend;
index index.html;
ssl_certificate /etc/nginx/certs/fullchain.pem;
ssl_certificate_key /etc/nginx/certs/privkey.pem;
add_header Strict-Transport-Security "max-age=31536000";
location / {
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-Proto https;
proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://meetup_frontend;
}
location /api {
try_files $uri #proxy_api;
}
location #proxy_api {
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-Proto https;
proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://meetup_backend;
}
location /ws {
try_files $uri #proxy_websocket;
}
location #proxy_websocket {
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-Proto https;
proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://meetup_ws;
}
}
And this is my docker-compose.yml
version: '3'
services:
nginx:
build: ./nginx
restart: always
ports:
- 80:80
- 443:443
volumes:
- ./nginx/default.conf:/etc/nginx/conf.d/default.conf
- ./frontend/build:/var/www/frontend
- ./nginx/certs:/etc/nginx/certs
depends_on:
- channels
db:
image: postgres:12.0-alpine
ports:
- 5432:5432
environment:
- POSTGRES_USER=postgres
- POSTGRES_HOST=db
- POSTGRES_PASSWORD=password
volumes:
- postgres_data:/var/lib/postgresql/data/
backend: &backend
build: ./backend
volumes:
- ./backend:/app
ports:
- 8000:8000
command: ["python", "manage.py", "runserver"]
env_file:
- ./.env
depends_on:
- db
- redis
frontend:
build: ./frontend
volumes:
- ./frontend:/app
- node_modules:/app/node_modules
ports:
- 8003:8003
command: npm start
stdin_open: true
redis:
image: "redis:5.0.7"
worker_channels:
<<: *backend
command: ["python", "manage.py", "runworker", "channels"]
depends_on:
- db
- redis
ports:
- 8002:8002
channels:
<<: *backend
command: daphne -b 0.0.0.0 -p 8001 backend.asgi:application
ports:
- 8001:8001
depends_on:
- db
- redis
volumes:
node_modules:
postgres_data:

Answer 1

It is a bit embarrassing why the issue existed but I was able to solve the issue. I did
ping frontend in my nginx container and it was successfully pinging the frontend container. Next I did curl -L http://frontend:8003 and it said curl: (7) Failed to connect to frontend port 8003: Connection refused. I went to the frontend container and did netstat -tulpn and it listed 3000 as the port that was exposed. I check my .env file and it was missing port=8003. Nginx was able to connect upstream afterwards.