c. Docker Compose

Two changes are needed in compose.yaml: add the nginx service as the new entry point, and update the gateway service to run as multiple replicas without an exposed port.

Add Nginx

  nginx:
    image: nginx:alpine
    hostname: nginx
    ports:
      - 8080:80
    volumes:
      - $SETUP/nginx/nginx.conf:/etc/nginx/nginx.conf:ro
    depends_on:
      - gateway

The volumes entry mounts the configuration file created in the previous step. The $SETUP variable must be defined in .env at the project root:

SETUP=./setup

Scale the Gateway

Remove the ports mapping from the gateway service and add a deploy block to set the replica count:

  gateway:
    build:
      context: ./gateway-service
      dockerfile: Dockerfile
    # ports removed — gateway is only reachable through nginx
    deploy:
      replicas: 3
    depends_on:
      - account
      - auth