Hosting Multiple Apps on One Droplet

When running multiple applications on a single server, proper configuration is essential to avoid conflicts and ensure each app runs smoothly. This guide explains how to host multiple applications on one DigitalOcean droplet using Nginx as a reverse proxy.

Key Points

Each app runs on a different port (8000 and 8001)
Both apps share the same IP address (128.199.2.146)
Nginx proxy routes traffic based on domain names

Files to update:

config/deploy.yml - update PORT and data directories + host domains
docker-compose.yml - update PORT and data directories
docker-startup.yml - update PORT

Changes to deploy.yml

Update the data directory for postgres data to create unique paths to avoid conflicts:

      - data:/var/lib/rightjoin-postgres/data

Why? In default config (in fleet app deploy.yml), the container path is /var/lib/postgresql/data (Postgres’s default data directory). In rightjoin app, the container path was /var/lib/rightjoin-postgres/data (a custom path)

/var/lib/rightjoin-data/postgres # update name with app name
/var/lib/rightjoin-data/redis

When Kamal sees this configuration, it will:

Create a directory on the host machine (likely at /root/fleet-postgres/data)
Mount this directory to /var/lib/rightjoin-postgres/data inside the container

Update the data directory for redis data to create unique paths to avoid conflicts: Rightjoin has a data directory for redis where fleet (Default) does not

For your Redis configuration in the fleet app, I don’t have a directories section, but kamal is automatically creating a volume for redis and mounting to /data inside the container. To create a separate dir, add config below similar to rightjoin redis config:

## docker hostname will be 'rightjoin-redis'
  redis:
    image: redis
    host: 128.199.2.146
    directories:
      - data:/data/rightjoin

Port Configuration

Set different ports in deploy.yml for each app

web:
  hosts:
    - 128.199.2.146
  options:
    expose: "8001"

Configure PORT environment variable

Port 8000 is the default in Kamal, and you only need to specify PORT in the environment when using a non-default port:

env:
  clear:
    DJANGO_SETTINGS_MODULE: rightjoin.settings_production
    ALLOWED_HOSTS: "rightjoin.co"
    USE_S3_MEDIA: 'True'
    AWS_STORAGE_BUCKET_NAME: 'rightjoin-media'
    STRIPE_LIVE_MODE: 'True'
    PORT: '8001'  # Add this for non-default port

Update proxy settings to match ports

proxy:
  ssl: true
  host: app.rightjoin.co
  app_port: 8001

Domain Setup

Configure DNS A records for both domains to point to the same IP:

Domain	Points to
app.rightjoin.co	128.199.2.146
customchatbot.ai	128.199.2.146

Kamal Deployment

Maintain separate deploy.yml for each app
Perform independent deployments using kamal redeploy
Services are defined by the current working directory

Database Configuration

Separate database instances

Configure unique database names and users for each application. Use different data directories to avoid conflicts by updating in docker-compose.yml and deploy.yml:

services:
  db:
    volumes:
      - postgres_data:/var/lib/rightjoin-postgres/data # where rightjoin is the app name

  redis:
    volumes:
      - redis_data:/data/rightjoin

By following these steps, you can successfully host multiple applications on a single droplet while keeping their configurations separate and secure.