Deploying Node.js and Python apps: VPS with Nginx, PM2, Gunicorn, Docker and platform-as-a-service options

// Express (Node.js)
const express = require("express");
const app = express();
app.get("/health", (req, res) => res.json({ ok: true }));
const port = process.env.PORT || 3000;
app.listen(port, "127.0.0.1", () => console.log("Listening on " + port));

# 1. Install Node.js (LTS) from the official NodeSource or nvm instructions, then:
node -v && npm -v

# 2. Get the code
cd /var/www && sudo mkdir myapp && sudo chown $USER:$USER myapp
git clone https://github.com/you/myapp.git myapp && cd myapp
npm ci --omit=dev

# 3. Environment variables in a protected file
nano .env            # PORT=3000, DATABASE_URL=..., chmod 600 .env

# 4. Run with PM2 (restarts on crash and on reboot)
sudo npm install -g pm2
pm2 start server.js --name myapp
pm2 save
pm2 startup          # run the command it prints to enable start on boot
pm2 logs myapp       # view logs

server {
    listen 80;
    server_name api.yourbusiness.co.ke;

    location / {
        proxy_pass http://127.0.0.1:3000;
        proxy_http_version 1.1;
        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;
        proxy_set_header Upgrade $http_upgrade;        # WebSockets
        proxy_set_header Connection "upgrade";
    }
}

sudo ln -s /etc/nginx/sites-available/myapp /etc/nginx/sites-enabled/
sudo nginx -t && sudo systemctl reload nginx

sudo apt install -y python3-venv
cd /var/www/myapp
python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt gunicorn
# Django extras: python manage.py migrate && python manage.py collectstatic

[Unit]
Description=My Python app
After=network.target

[Service]
User=deploy
WorkingDirectory=/var/www/myapp
EnvironmentFile=/var/www/myapp/.env
ExecStart=/var/www/myapp/venv/bin/gunicorn --workers 3 --bind 127.0.0.1:8000 app:app
Restart=always

[Install]
WantedBy=multi-user.target

sudo systemctl daemon-reload
sudo systemctl enable --now myapp
sudo systemctl status myapp
journalctl -u myapp -f        # logs

location /static/ { alias /var/www/myapp/static/; }

sudo apt install -y certbot python3-certbot-nginx
sudo certbot --nginx -d api.yourbusiness.co.ke
sudo certbot renew --dry-run

FROM node:20-alpine
WORKDIR /app
COPY package*.json ./
RUN npm ci --omit=dev
COPY . .
ENV NODE_ENV=production
EXPOSE 3000
CMD ["node", "server.js"]

services:
  app:
    build: .
    env_file: .env
    ports: ["127.0.0.1:3000:3000"]
    depends_on: [db]
    restart: unless-stopped
  db:
    image: postgres:16
    environment:
      POSTGRES_PASSWORD: ${DB_PASSWORD}
    volumes: [dbdata:/var/lib/postgresql/data]
    restart: unless-stopped
volumes:
  dbdata:

docker compose up -d --build
docker compose logs -f app

#!/bin/bash
set -euo pipefail
cd /var/www/myapp
git pull --ff-only
npm ci --omit=dev
pm2 reload myapp          # graceful reload with no downtime for clustered apps
curl -fsS http://127.0.0.1:3000/health