A/B testing with split_clients in Nginx - Mini Project: Build & Apply

A/B Testing with split_clients in Nginx

📖 Scenario: You are working as a web server administrator. Your website wants to test two different versions of a landing page to see which one users like better. This is called A/B testing.You will use Nginx's split_clients module to send 50% of visitors to version A and 50% to version B.

🎯 Goal: Build an Nginx configuration that uses split_clients to assign visitors to either variant_a or variant_b evenly based on their IP address.This will help the website show different content to different users for testing.

📋 What You'll Learn

Create a variable called $variant using split_clients

Split traffic 50% to variant_a and 50% to variant_b

Use $remote_addr as the key for splitting

Add a server block listening on port 8080

Return the assigned variant in the response body

💡 Why This Matters

🌍 Real World

Websites often want to test different versions of pages to improve user experience. Using Nginx's split_clients lets you do this easily at the server level.

💼 Career

DevOps engineers and site reliability engineers use Nginx configurations like this to manage traffic and run experiments without changing application code.

1

Create basic Nginx server block

Create an Nginx server block that listens on port 8080 and returns the text "Hello from Nginx" for any request.

Nginx

server {
    listen 8080;
    location / {
        # Your code here
    }
}

Need a hint?

Use return 200 "Hello from Nginx"; inside the location / block.

2

Add split_clients block to define $variant

Add a split_clients block inside the server block that creates a variable called $variant. Use $remote_addr as the key. Split traffic 50% to variant_a and 50% to variant_b.

Nginx

server {
    listen 8080;

    # Your code here

    location / {
        return 200 "Hello from Nginx";
    }
}

Need a hint?

Use split_clients "$remote_addr" $variant { 50% variant_a; * variant_b; } inside the server block.

3

Modify location block to return the variant

Change the location / block to return the text "User assigned to: $variant" using the return directive.

Nginx

server {
    listen 8080;

    split_clients "$remote_addr" $variant {
        50% variant_a;
        *    variant_b;
    }

    location / {
        # Your code here
    }
}

Need a hint?

Use return 200 "User assigned to: $variant"; inside the location / block.

4

Test the configuration output

Run the Nginx server and send a request to http://localhost:8080/. The response should be either User assigned to: variant_a or User assigned to: variant_b depending on your IP.

Nginx

# Run the server and test the output
# Your code here

Need a hint?

Use curl http://localhost:8080/ to test the response.