Correct nginx.conf loadbalancing to uvicorn FastAPI with docker-compose

Question

I want to use nginx as load balancer to my FastAPI replicas but i cannot get it to work. I read that uvicorn can also do it, but nginx would handle load balancing nicely. forum post.

I get an error

host not found in upstream "inconnect1:5001"

docker-compose.yml

version: "3"

networks:
  proxy-tier:
    external:
      name: nginx-proxy

services:

  inconnect1: 
    image: inconnect:0.1
    container_name: inconnect1
    environment:
      - PORT=5001
    volumes:
      - ./inconnect/app:/app
    ports:
      - 5001:5001

  nginx: 
    image: jwilder/nginx-proxy
    container_name: nginx
    ports:
      - 80:80
      - 443:443
    volumes:
      - /var/run/docker.sock:/tmp/docker.sock:ro
      - ./letsencrypt/certs:/etc/nginx/certs:ro
      - ./nginx/nginx.conf:/etc/nginx/nginx.conf
    networks:
      - proxy-tier
    restart: always
    deploy:
      mode: replicated
      replicas: 1

nginx.conf

worker_processes 1;

events { worker_connections 1024; }

http {

sendfile on;

upstream restapis {
server inconnect:5001;
}

server {
listen 80;

location / {
  proxy_set_header Host $http_host;
  proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
  proxy_set_header X-Forwarded-Proto $scheme;
  proxy_redirect off;
  proxy_buffering off;
  proxy_pass http://restapis;
}

location /static {
  # path for static files
  root /path/to/app/static;
}
}
 }

Answer 1

As your nginx.conf file :

server inconnect:5001; should be server inconnect1:5001;

And in docker compose file should use link from nginx container to inconnect1 application. (remove network on nginx container)

    image: jwilder/nginx-proxy
    container_name: nginx
    ports:
      - 80:80
      - 443:443
    volumes:
      - /var/run/docker.sock:/tmp/docker.sock:ro
      - ./letsencrypt/certs:/etc/nginx/certs:ro
      - ./nginx/nginx.conf:/etc/nginx/nginx.conf
    links:
      - "inconnect1:inconnect1"
    restart: always
    deploy:
      mode: replicated
      replicas: 1

Or use on 1 network:

networks:
  proxy-tier:
    driver: bridge

services:

  inconnect1: 
    image: inconnect:0.1
    container_name: inconnect1
    environment:
      - PORT=5001
    volumes:
      - ./inconnect/app:/app
    ports:
      - 5001:5001
    networks:
      - proxy-tier

  nginx: 
    image: jwilder/nginx-proxy
    container_name: nginx
    ports:
      - 80:80
      - 443:443
    volumes:
      - /var/run/docker.sock:/tmp/docker.sock:ro
      - ./letsencrypt/certs:/etc/nginx/certs:ro
      - ./nginx/nginx.conf:/etc/nginx/nginx.conf
    networks:
      - proxy-tier
    restart: always
    deploy:
      mode: replicated
      replicas: 1