Configuring the request limiting

Configuring the request limiting

The ngx_http_limit_req_module module limits the request processing rate per a defined key. The module directives include the mandatory limit_req_zone and limit_req directives and an optional limit_req_status directive.

The limit_req_zone directive defines the parameters for the rate limiting.

Syntax

limit_req_zone key zone=name:size rate=rate [sync];

Default

Context

HTTP

NGINX configuration sample

limit_req_zone $binary_remote_addr zone=global_limit_zone1:10m rate=1r/s ;
limit_req_zone $ip_limit_action zone=global_limit_zone2:10m rate=2r/s ;

The limit_req directive enables rate limiting within the context where it appears.

Syntax

limit_req zone=name [burst=number] [nodelay | delay=number];

Default

Context

HTTP, server, location

NGINX configuration sample

limit_req zone=global_limit_zone1 burst=2 ;
limit_req zone=global_limit_zone2 burst=4 nodelay ;

The limit_req_status directive sets the status code to return in response to rejected requests.

Syntax

limit_req_status code;

Default

limit_req_status 503;

Context

http, server, location that corresponds to the nginx:server and nginx:server:site definitions of a pillar.

NGINX configuration sample

limit_req_status 429;

Example of a Salt pillar for limit_req_zone and limit_req:

nginx:
server:
  limit_req_module:
    limit_req_zone:
      global_limit_zone1:
        key: binary_remote_addr
        size: 10m
        rate: '1r/s'
      global_limit_zone2:
        key: ip_limit_action
        size: 10m
        rate: '2r/s'
    limit_req_status: 429
    limit_req:
      global_limit_zone1:
        burst: 2
        enabled: true
      global_limit_zone2:
        burst: 4
        enabled: true
        nodelay: true

In the configuration example above, the states are kept in a 10 megabyte global_limit_zone1 and global_limit_zone2 zones. An average request processing rate cannot exceed 1 request per second for global_limit_zone1 and 2 requests per second for global_limit_zone2.

The $binary_remote_addr, a client’s IP address, serves as a key for the global_limit_zone1 zone. And the mapped $ip_limit_action variable is a key for the global_limit_zone2 zone.

To apply the request limiting to a particular site, define the limit_req on a site level. For example:

nginx:
  server:
    site:
      nginx_proxy_openstack_api_keystone:
        limit_req_module:
          limit_req:
            global_limit_zone:
              burst: 5
              nodelay: true
              enabled: true