PM2 for Node.js: Production Process Management Guide

Running node server.js in a terminal is fine for testing, but the app dies when you close the session, crashes stay down, and nothing starts it again after a reboot. PM2 is a widely used process manager for Node.js that fixes all three, and adds cluster mode, log handling and memory limits. This guide is for a Linux VPS or server you manage yourself, not for shared hosting.

1. Before you start

• A server you control. A VPS with SSH access and the right to install software. On Domain India shared hosting you can't run your own long-lived processes; see section 9 for the options there.
• A current Node.js LTS release. Use Node.js 24 LTS or 22 LTS. Node.js 18 and 20 have reached end of life; don't start new projects on them.
• A non-root user that owns the app, for example deploy. Run your app as that user, not as root.
• An app that starts from the command line, with node server.js or npm start.

2. Install PM2 and start your app

sudo npm install -g pm2
pm2 --version

Then, as your app user, from the app folder:

pm2 start server.js --name my-app      # a single script
pm2 start npm --name my-app -- start   # or an npm script
pm2 list                                # status, CPU, memory, restarts

The day-to-day commands:

pm2 logs my-app       # follow the logs
pm2 restart my-app    # stop and start again
pm2 reload my-app     # zero-downtime restart in cluster mode
pm2 stop my-app       # stop, keep it in the list
pm2 delete my-app     # remove it from PM2

3. Describe the app in an ecosystem file

Command-line flags are easy to forget. Put the configuration in ecosystem.config.js in your project and commit it to Git:

module.exports = {
  apps: [{
    name: 'my-app',
    cwd: '/home/deploy/my-app',
    script: './server.js',
    instances: 2,
    exec_mode: 'cluster',
    max_memory_restart: '500M',
    env_production: { NODE_ENV: 'production', PORT: 3000 },
    time: true,
  }],
};

Start it with pm2 start ecosystem.config.js --env production. Anyone on your team can now reproduce the exact setup from one file. Keep secrets such as database passwords in a .env file or your server's environment, not in the ecosystem file you commit.

4. Cluster mode and zero-downtime reloads

One Node.js process uses one CPU core. In cluster mode, PM2 runs several workers that share the same port:

• instances: 'max' starts one worker per core; a number such as 2 sets it exactly. On a small VPS, leave room for the database and the OS.
• pm2 reload my-app replaces workers one at a time, so a worker is always answering. pm2 restart stops everything at once.

Cluster mode needs a little care:

• In-memory state is per worker. Sessions, caches and rate limits held in memory are not shared. Keep them in a database or a shared store.
• Scheduled jobs run once per worker. Run cron-style jobs in a separate app with instances: 1, or behind a lock.
• WebSockets need sticky sessions across workers, for example with @socket.io/sticky, or run WebSocket apps with instances: 1.

For deploys that build each release in its own folder and switch over with a health check, see Zero-Downtime Deploys with PM2 and Git Hooks.

5. Logs and log rotation

PM2 writes each app's output to ~/.pm2/logs/. Read them with:

pm2 logs my-app --lines 200   # last 200 lines, then follow
pm2 logs my-app --err         # errors only

Those files grow forever unless you rotate them:

pm2 install pm2-logrotate
pm2 set pm2-logrotate:max_size 10M
pm2 set pm2-logrotate:retain 10
pm2 set pm2-logrotate:compress true

That rotates each log at 10 MB, keeps 10 old files and compresses them. For central logging across several servers, ship the logs to a tool such as Grafana Loki.

6. Start automatically after a reboot

Run pm2 save again whenever you add or remove an app. After upgrading Node.js, run pm2 update and repeat pm2 startup, because the service records the path to Node.

7. Put a reverse proxy in front

Don't expose port 3000 to the internet. Bind the app to 127.0.0.1 and let nginx or Caddy handle HTTPS and forward requests to it. A minimal nginx block:

server {
    server_name example.com;
    location / {
        proxy_pass http://127.0.0.1:3000;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}

Add a certificate with Certbot, or use Caddy, which obtains one automatically. Allow only ports 22, 80 and 443 in your firewall.

8. Monitoring and common problems

pm2 monit shows live CPU, memory and logs for each process. max_memory_restart restarts a worker that grows past its limit, which buys time while you find a memory leak. For a hard limit on everything PM2 runs, set MemoryMax= on the systemd service.

Alternatives: a plain systemd unit per app suits a single app with no cluster mode. Docker Compose suits you if everything else already runs in containers.

9. Running Node.js on Domain India

VPS plans are self-managed and come without cPanel. See VPS plans, the App Platform, or How to Deploy a Node.js App on Shared Hosting.

Prices on the cards exclude 18% GST.

Ready to deploy? Compare VPS plans for full control with PM2, or the App Platform if you'd rather not manage a server at all.