Hosting on Amazon EC2 with Nginx: Custom Document Roots and Multi-Port Routing.

Deploying a web server in the cloud involves two synchronized layers: configuring the Linux operating system inside the virtual machine, and configuring network traffic policies in AWS.

Once you know how to install a daemon like Apache or Nginx, the next step is learning how to direct web traffic to custom project directories and expose different applications over distinct TCP ports.

Here is a step-by-step breakdown of configuring Nginx on Amazon EC2, mapping custom document roots, and handling multi-port routing.

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1. Service Lifecycle Management on Linux

Modern Linux distributions rely on systemd to manage background services. Once Nginx is installed via your package manager, service management follows three essential commands:

• Start the service immediately:
sudo systemctl start nginx

• Ensure the daemon starts automatically if the EC2 instance reboots:
sudo systemctl enable nginx

• Inspect the running processes and service health:
sudo systemctl status nginx

Checking the status output confirms that systemd has spawned both the Nginx master process and its associated worker processes.

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2. Customizing the Document Root and Index Directives

By default, Nginx serves static assets from standard locations such as /usr/share/nginx/html or /var/www/html. In production environments, applications rarely sit in the default directory.

To point incoming traffic to a specific project folder:

1. Create a dedicated application directory:
sudo mkdir /usr/share/nginx/html/website

2. Move your project files (HTML, CSS, assets) into that folder.

3. Edit the primary configuration file located at /etc/nginx/nginx.conf. Inside the `server` block, locate and update the `root` and `index` directives:

server {
listen 80;
server_name _;
root /usr/share/nginx/html/website;
index app.html index.html;
...
}

• root: Tells Nginx which directory on the filesystem contains the site files.
• index: Tells Nginx which file to serve as the default landing page when a user hits the base URL.

After updating the configuration, always reload or restart the service to apply the new directives:
sudo systemctl restart nginx

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3. Multi-Port Web Hosting on a Single EC2 Instance

A single EC2 instance can host multiple web applications by binding separate Nginx server blocks to different TCP ports.

For example, you can serve a corporate marketing portal on the standard HTTP port (Port 80) and run a separate user dashboard or clone interface on Port 81.

Inside /etc/nginx/nginx.conf, you can define a secondary server block:

server {
listen 81;
server_name _;
root /usr/share/nginx/html/second-app;
index index.html;
}

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4. Synchronizing AWS Security Groups

A running web server will remain unreachable from the public internet until the cloud firewall permits incoming connections.

To make custom ports reachable:

1. Navigate to the EC2 Console > Instances and select your instance.
2. Under the Security tab, click on the attached Security Group.
3. Edit Inbound Rules and add:
• Type: Custom TCP
• Port Range: 81
• Source: 0.0.0.0/0 (or your specific IP address)
4. Save the rules.

Once saved, the AWS hypervisor permits traffic to pass through to the instance, allowing users to reach the secondary application directly at:
http://<EC2-Public-IP>:81

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Key Takeaways

1. Document roots are flexible: You are not restricted to default web directories; Nginx allows you to define custom paths for each project.
2. Explicit entry points: The `index` directive provides full control over the exact entry file served to clients.
3. Defense in depth: A service running on Linux requires both internal process management (systemd) and cloud perimeter authorization (AWS Security Groups) to be accessible.