Beginner's Guide to Nginx

Nginx (pronounced "engine-x") is a high-performance, open-source web server and reverse proxy server. It is widely used for serving static and dynamic content, handling reverse proxying, load balancing, and acting as an API gateway.

Why is Nginx Used?

Nginx is popular because of its:

1. High Performance – Handles thousands of connections with low memory usage.

2. Reverse Proxy – Forwards client requests to backend servers (e.g., Node.js, Python, PHP).

3. Load Balancing – Distributes traffic among multiple servers.

4. Security Features – Blocks malicious traffic, prevents DDoS attacks.

5. Static File Serving – Efficiently serves HTML, CSS, JS, images, etc.

6. SSL/TLS Support – Secures websites with HTTPS.

7. Caching – Improves website speed by storing frequently accessed content.

You will mainly use it as Reverse proxy, API gateway, load balancing and for managing SSL certificates

How Nginx Works?

1. A user sends a request to a domain (e.g., example.com).

2. The request reaches Nginx, which decides how to handle it:

   • If it’s for static content, Nginx serves it directly.

   • If it’s for dynamic content, Nginx forwards it to a backend (e.g., Node.js running on port 3000).

3. If configured as a reverse proxy, Nginx acts as an intermediary between clients and backend servers.

4. If acting as a load balancer, Nginx distributes traffic across multiple backend servers.

5. It logs requests, applies security rules, and optimizes performance.

By default nginx server runs on port 80 which is a http port. So if you are running nginx on your local system then it will run 127.0.0.1 If you visit 127.0.0.1 in your browser then you will see default nginx page.

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Installing Nginx

1. Installing it locally on your system

https://nginx.org/en/download.html

2. Installing it in a Docker container.

You should have docker installed in your machine.

1. Pull the Official Nginx Docker Image

docker pull nginx

This downloads the latest official Nginx image from Docker Hub.

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2. Run Nginx Container

docker run --name my-nginx -d -p 80:80 nginx

Explanation:

• docker run → Runs a new container

• --name my-nginx → Assigns a custom name to the container

• -d → Runs in detached mode (in the background)

• -p 80:80 → Maps container port 80 to host port 80

• nginx → Uses the nginx image

Now, open http://localhost in a browser, and you should see the default Nginx welcome page.

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3. Check Running Containers

docker ps

To see all containers (including stopped ones):

docker ps -a

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4. Stop, Start, and Restart Nginx Container

• Stop Nginx container

    docker stop my-nginx
  

• Start Nginx container

    docker start my-nginx
  

• Restart Nginx container

    docker restart my-nginx
  

  ```

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5. Customize Nginx Configuration

To use a custom nginx.conf, create a directory and file:

mkdir ~/nginx
cd ~/nginx
nano nginx.conf

Paste a simple config:

events { worker_connections 1024; }
http {
    server {
        listen 80;
        server_name localhost;
        location / {
            root /usr/share/nginx/html;
            index index.html;
        }
    }
}

Run the container with your custom config:

docker run --name my-nginx -d -p 80:80 -v ~/nginx/nginx.conf:/etc/nginx/nginx.conf nginx

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6. Remove Nginx Container

To stop and remove the container:

docker stop my-nginx
docker rm my-nginx

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Summary of Key Commands

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3. Installing it on Linux server.

Nginx can be installed on different Linux distributions like Ubuntu, Debian, CentOS, RHEL, and Arch Linux. Below are the step-by-step installation instructions.

1. Update Your System Packages

Before installing Nginx, update the system package list.

sudo apt update && sudo apt upgrade -y   # For Ubuntu/Debian
sudo yum update -y                       # For CentOS/RHEL

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2. Install Nginx

For Ubuntu/Debian

sudo apt install nginx -y

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3. Start and Enable Nginx Service

After installation, start and enable Nginx to launch automatically on system boot using [[Advance Linux commands#How to manage systemd services?|systemctl]]

sudo systemctl start nginx      # Start Nginx
sudo systemctl enable nginx     # Enable auto-start on boot

To check if Nginx is running:

sudo systemctl status nginx

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4. Allow Nginx Through Firewall (If Enabled)

If a firewall is enabled, allow Nginx traffic.

For UFW (Ubuntu/Debian)

sudo ufw allow 'Nginx Full'
sudo ufw reload
sudo ufw status

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5. Verify Installation

To check if Nginx is installed and running, open a web browser and visit:

http://YOUR_SERVER_IP

If you see the "Welcome to Nginx" page, Nginx is installed and running successfully.

You can also test it from the terminal:

curl -I http://localhost

Expected output:

HTTP/1.1 200 OK
...
Server: nginx/1.x.x

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6. Manage Nginx Service

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Nginx configuration

Nginx's configuration file (nginx.conf) controls how the web server behaves, manages connections, and processes requests. Below, I'll explain its structure and key directives.

Location: - /etc/nginx/nginx.conf

To edit the configuration file:

sudo cat /etc/nginx/nginx.conf

After making changes, reload Nginx:

sudo systemctl reload nginx

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2. Nginx Configuration Structure

A basic nginx.conf looks like this:

user www-data;
worker_processes auto;

events{

}

http{
    server{
        location / {

        }
    }
}

mail{

}

user  www-data;
worker_processes  auto;

events {
    worker_connections  1024;
}

http {
    include       mime.types;
    default_type  application/octet-stream;

    sendfile        on;
    keepalive_timeout  65;

    server {
        listen       80;
        server_name  example.com;

        location / {
            root   /var/www/html;
            index  index.html index.htm;
        }

        error_page  404 /404.html;
        location = /404.html {
            root /var/www/html;
        }
    }
}

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3. Breakdown of Configuration Sections

1️⃣ Global Settings

These are at the top level of nginx.conf and apply to the whole server.

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2️⃣ events {} Block

This section handles connection-related settings.

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3️⃣ http {} Block

This section manages HTTP-related settings, including MIME types, logging, and request handling. Http block can have single or multiple server block.

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4️⃣ server {} Block

Each server {} block defines a virtual host (website) in Nginx.

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5️⃣ location {} Blocks

These define request-handling rules.

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4. Advanced Configurations

🔹 Reverse Proxy Example

If you have an app running on port 3000, you can set up a reverse proxy:

server {
    listen 80;
    server_name example.com;

    location / {
        proxy_pass http://localhost:3000;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }
}

Now, requests to http://example.com will be forwarded to http://localhost:3000.

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🔹 Load Balancing Example

If you have multiple backend servers, you can distribute requests:

upstream backend_servers {
    server backend1.example.com;
    server backend2.example.com;
}

server {
    listen 80;
    server_name example.com;

    location / {
        proxy_pass http://backend_servers;
    }
}

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5. Managing Nginx

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https://youtu.be/NwijBVfiK_o