Massed Compute

Create VM Instance

Log in to the Massed Compute dashboard and create a new CPU VM:

• Image: Ubuntu Server 24.04 LTS
• Size: cpu_mini_amd_epyc or larger
• Region: Choose your preferred location
• SSH Keys: Add your public key for secure access

Wait for the VM to reach the running state before proceeding.

Configure DNS (For HTTPS)

If you want automatic HTTPS with Let’s Encrypt certificates, point your domain’s DNS records to your VM’s public IP:

your-domain.com   A     YOUR_VM_IP
www.your-domain.com   CNAME   your-domain.com

For testing without a domain, you can use HTTP on port 80 only.

Connect to Your VM

SSH into your VM using the connection details from your dashboard:

ssh -i ~/.ssh/your-key ubuntu@YOUR_VM_IP

Update System and Add Caddy Repository

Update your system and add the official Caddy repository:

sudo apt update
sudo apt install -y debian-keyring debian-archive-keyring apt-transport-https curl

# Add Caddy's official GPG key
curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/gpg.key' | sudo gpg --dearmor -o /usr/share/keyrings/caddy-stable-archive-keyring.gpg

# Add Caddy repository
curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/debian.deb.txt' | sudo tee /etc/apt/sources.list.d/caddy-stable.list

Install Caddy

Update the package list and install Caddy:

sudo apt update
sudo apt install -y caddy

Configure Firewall

Open the necessary ports for web traffic:

sudo ufw allow OpenSSH
sudo ufw allow 80/tcp
sudo ufw allow 443/tcp
sudo ufw --force enable

Create Caddy Configuration

Create a Caddyfile to configure your reverse proxy. For HTTPS with a domain:

sudo nano /etc/caddy/Caddyfile

Add this configuration (replace YOUR_DOMAIN and YOUR_PORT):

your-domain.com {
    reverse_proxy 127.0.0.1:8188  # ComfyUI example
    # reverse_proxy 127.0.0.1:11434  # Ollama example  
    # reverse_proxy 127.0.0.1:8080   # FastAPI example
}

For HTTP testing without a domain:

:80 {
    reverse_proxy 127.0.0.1:8188
}

Start a Demo Upstream Service (Optional)

If you don’t have a service running yet, create a simple demo server for testing:

# Create demo service
sudo tee /etc/systemd/system/demo-upstream.service > /dev/null << 'EOF'
[Unit]
Description=Demo upstream service
After=network-online.target

[Service]
ExecStart=/usr/bin/python3 -m http.server 8188 --bind 127.0.0.1 --directory /var/www/demo
Restart=on-failure

[Install]
WantedBy=multi-user.target
EOF

# Create demo content
sudo mkdir -p /var/www/demo
echo "" | sudo tee /var/www/demo/index.html

# Start demo service
sudo systemctl daemon-reload
sudo systemctl enable --now demo-upstream

Validate and Start Caddy

Validate your configuration and start Caddy:

sudo caddy validate --config /etc/caddy/Caddyfile
sudo systemctl enable --now caddy
sudo systemctl reload caddy

Check Service Status

Verify that Caddy and your upstream service are running:

sudo systemctl status caddy
sudo systemctl status demo-upstream  # if using demo

# Check listening ports
sudo ss -tlnp | grep -E ':80|:443|:8188'

Test Local Connection

Test the reverse proxy from within the VM:

# Test direct upstream
curl -s http://127.0.0.1:8188/

# Test through Caddy
curl -s http://127.0.0.1/

Test External Access

From your local machine, test the proxy:

# HTTP test
curl -s http://YOUR_VM_IP/

# HTTPS test (if domain configured)
curl -s https://your-domain.com/

You should see your upstream service content through Caddy.