Scaling Pluma

The api service is stateless — run multiple replicas behind nginx. Docker DNS handles discovery automatically.

nginx.conf


events {}
 
http {
  resolver 127.0.0.11 valid=30s; # Docker embedded DNS
 
  upstream api_backend {
    server api:2137;
  }
 
  server {
    listen 80;
 
    location / {
      proxy_pass         http://api_backend;
      proxy_set_header   Host              $host;
      proxy_set_header   X-Real-IP         $remote_addr;
      proxy_set_header   X-Forwarded-For   $proxy_add_x_forwarded_for;
      proxy_set_header   X-Forwarded-Proto $scheme;
    }
  }
}

docker-compose.yml changes

Remove ports from the api service, add deploy.replicas, and add an nginx service:


api:
  image: ghcr.io/403-html/pluma-api:v1.3.0
  environment:
    DATABASE_URL: postgresql://${DB_USER:-pluma}:${DB_PASSWORD:-pluma}@db:5432/${DB_NAME:-pluma}?schema=public
  depends_on:
    db:
      condition: service_healthy
  deploy:
    replicas: 3
 
nginx:
  image: nginx:alpine
  ports:
    - "80:80"
  volumes:
    - ./nginx.conf:/etc/nginx/nginx.conf:ro
  depends_on:
    - api

Scale

Scale the API to any number of replicas:


docker compose up -d --scale api=N

Replace N with the desired number of instances.

Verify

Confirm that Docker DNS resolves all replicas:


docker compose exec nginx nslookup api