A/B testing with split_clients in Nginx - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the split_clients directive in nginx?

The split_clients directive is used to divide incoming traffic into different groups or buckets for A/B testing or traffic splitting based on a variable like client IP or cookie.

beginner

How does split_clients assign users to different groups?

It uses a hashing function on a variable (like $remote_addr) to consistently assign users to groups with specified percentages, ensuring the same user sees the same variant.

intermediate

Write a simple split_clients example that splits traffic 50/50 between two groups named variant_a and variant_b.

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

intermediate

Why is it important that split_clients uses a consistent hashing method?

Consistency ensures that the same user is always assigned to the same group, which avoids confusion and maintains a stable user experience during A/B testing.

intermediate

Can split_clients be used with any variable? Give an example.

Yes, it can use any variable like $cookie_user, $remote_addr, or $request_uri. For example, splitting by cookie: <br>split_clients "$cookie_user" $group {<br> 30% "test";<br> * "control";<br>}

What does the split_clients directive in nginx primarily do?

A Splits traffic into groups for testing

B Blocks unwanted IP addresses

C Caches static files

D Redirects users to HTTPS

split_clients is used to divide traffic into groups for A/B testing or traffic splitting.

Which variable is commonly used with split_clients to assign users consistently?

A $http_user_agent

B $remote_addr

C $request_method

D $server_name

$remote_addr (client IP) is commonly used to consistently assign users to groups.

In split_clients "$remote_addr" $group { 50% "A"; * "B"; }, what does the asterisk (*) mean?

A Multiply percentage by 2

B End of configuration

C Default catch-all group

D Ignore this group

The asterisk (*) is the default catch-all for remaining traffic not matched by previous percentages.

Why is consistent user assignment important in A/B testing with split_clients?

A To keep user experience stable

B To speed up server response

C To reduce bandwidth usage

D To encrypt user data

Consistent assignment ensures users see the same variant, keeping their experience stable.

Can split_clients split traffic based on cookies?

A No, only server variables

B No, only IP addresses

C No, only request headers

D Yes, it can use cookie variables

split_clients can use any variable, including cookies, for splitting traffic.

Explain how nginx's split_clients directive helps in A/B testing and why consistent user assignment matters.

Think about how you would divide visitors into groups and keep them seeing the same version.

Describe a simple nginx configuration using split_clients to split traffic 70% to group A and 30% to group B.

Remember to use the asterisk (*) for the remaining percentage.