Split Clients#
The module emits variables for A/B testing, canary releases, or other scenarios that require routing a percentage of clients to one server or configuration while directing the rest elsewhere.
Configuration Example#
http {
split_clients "${remote_addr}AAA" $variant {
0.5% .one;
2.0% .two;
* "";
}
server {
location / {
index index${variant}.html;
Directives#
split_clients#
Creates a $variable by hashing the string; the variables in string are substituted, the result is hashed, then the hash is mapped to the $variable’s string value.
The hash function uses
MurmurHash2
(32-bit),
and its entire value range
(0 to 4294967295)
is mapped to buckets in order of appearance;
the percentages determine the size of the buckets.
A wildcard (*
) may occur last;
hashes that fall outside other buckets are mapped to its assigned value.
An example:
split_clients "${remote_addr}AAA" $variant {
0.5% .one;
2.0% .two;
* "";
}
Here, the hashed values of the interpolated $remote_addrAAA
string
are distributed as follows:
values 0 to 21474835 (a sample of 0.5%) yield
.one
values 21474836 to 107374180 (a sample of 2%) yield
.two
values 107374181 to 4294967295 (all other values) yield
""
(an empty string)