How to deploy a SvelteKit application on a VPS with PM2 and Nginx

Here’s a parallel walkthrough for deploying your SvelteKit app on an Ubuntu VPS, managed by PM2 and fronted by Nginx:

1. VPS Prep & SSH Access

Provision your VPS, e.g. Ubuntu 22.04 LTS on DigitalOcean, AWS EC2, etc.
Ensure SSH (port 22) is open, or configure your custom SSH port.
SSH in:
```
ssh root@your_server_ip
```

2. System Update & Node.js Installation

# Update system packages
sudo apt update && sudo apt upgrade -y

# Install curl & build essentials
sudo apt install -y curl build-essential

# Install Node.js LTS via NodeSource
curl -fsSL https://deb.nodesource.com/setup_lts.x | sudo -E bash -
sudo apt install -y nodejs

Verify:

node -v    # e.g. v18.x
npm -v     # e.g. v9.x

3. Create a Deployment User (Optional)

sudo adduser deployer
sudo usermod -aG sudo deployer

Then exit and re-SSH as deployer for safer ops.

4. Clone & Build Your SvelteKit App

Navigate to your apps directory:

mkdir -p ~/apps/sveltekit-app && cd ~/apps/sveltekit-app

Clone your repo:

git clone https://github.com/yourusername/your-sveltekit-repo.git .

Install deps & build:

npm ci           # or yarn install --frozen-lockfile
npm run build

5. Configure PM2 to Run SvelteKit

Install PM2 globally:
```
npm install -g pm2
```
Start your SvelteKit app:
```
pm2 start node --name "sveltekit-app" -- .svelte-kit/node/server/index.js
```
Note: The entry path may vary by adapter; adjust if you’re using @sveltejs/adapter-node or another adapter.

Optional: Create an ecosystem file:

pm2 ecosystem

Edit ecosystem.config.js to point at your build output, e.g.:

module.exports = {
  apps: [
    {
      name: "sveltekit-app",
      script: ".svelte-kit/node/server/index.js",
      cwd: "/home/deployer/apps/sveltekit-app",
      instances: "max",
      exec_mode: "cluster",
      env: { NODE_ENV: "production" }
    }
  ]
};

Start via ecosystem:
```
pm2 start ecosystem.config.js
```

Persist PM2 across reboots:

pm2 save
pm2 startup systemd
# Follow the instructions printed to enable

6. Install & Configure Nginx

Install Nginx:
```
sudo apt install -y nginx
```

Create Nginx site file at /etc/nginx/sites-available/sveltekit-app:

server {
  listen 80;
  server_name your_domain_or_ip;

  location / {
    proxy_pass http://127.0.0.1:3000;      # SvelteKit default port
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection 'upgrade';
    proxy_set_header Host $host;
    proxy_cache_bypass $http_upgrade;
  }

  # Serve static assets directly
  location /_app/ {
    alias /home/deployer/apps/sveltekit-app/static/;
    access_log off;
    expires max;
  }
}

Enable & reload:

sudo ln -s /etc/nginx/sites-available/sveltekit-app /etc/nginx/sites-enabled/
sudo nginx -t
sudo systemctl reload nginx

7. (Optional) Secure with Let’s Encrypt SSL

Install Certbot:

sudo apt install -y certbot python3-certbot-nginx

Obtain & configure cert:

sudo certbot --nginx -d your_domain.com -d www.your_domain.com

Auto-renewal runs by default via cron/systemd.

8. Monitoring & Logs

Check PM2 status:
```
pm2 status
```
View logs:
```
pm2 logs sveltekit-app --lines 100
```

Dev mode with auto-restart:

pm2 start npm --name "sveltekit-dev" --watch -- run dev

Recap of Key Commands

# System & Node
sudo apt update && sudo apt upgrade -y
curl -fsSL https://deb.nodesource.com/setup_lts.x | sudo -E bash -
sudo apt install -y nodejs nginx

# Clone & build
git clone repo .
npm ci && npm run build

# PM2
npm install -g pm2
pm2 start node --name "sveltekit-app" -- .svelte-kit/node/server/index.js
pm2 save && pm2 startup systemd

# Nginx
# create /etc/nginx/sites-available/sveltekit-app (as above)
sudo ln -s /etc/nginx/sites-available/sveltekit-app /etc/nginx/sites-enabled/
sudo nginx -t && sudo systemctl reload nginx

# SSL (optional)
sudo apt install -y certbot python3-certbot-nginx
sudo certbot --nginx -d your_domain.com

With this setup, your SvelteKit application will run under PM2—automatically restarting on crashes or reboots—and be served securely behind Nginx.