Configuring the connection limiting

Configuring the connection limiting

The ngx_http_limit_conn_module module limits the number of connections per defined key. The main directives include limit_conn_zone and limit_conn.

The limit_conn_zone directive sets parameters for a shared memory zone that keeps states for various keys. A state is the current number of connections. The key value can contain text, variables, and their combination. The requests with an empty key value are not accounted.

Syntax

limit_conn_zone key zone=name:size;

Default

Context

HTTP

NGINX configuration sample

limit_conn_zone $binary_remote_addr zone=global_limit_conn_zone:20m;
limit_conn_zone $binary_remote_addr zone=openstack_web_conn_zone:10m;

The limit_conn directive sets the shared memory zone and the maximum allowed number of connections for a given key value. When this limit is exceeded, the server returns the error in reply to a request.

Syntax

limit_conn zone number;

Default

Context

HTTP, server, location

NGINX configuration sample

limit_conn global_limit_conn_zone 100;
limit_conn_status 429;

Example of a Salt pillar with limit_conn_zone and limit_conn:

nginx:
  server:
    limit_conn_module:
      limit_conn_zone:
        global_limit_conn_zone:
          key: 'binary_remote_addr'
          size: 20m
          enabled: true
        api_keystone_conn_zone:
          key: 'binary_remote_addr'
          size: 10m
          enabled: true
      limit_conn:
        global_limit_conn_zone:
          connections: 100
          enabled: true
      limit_conn_status: 429

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

nginx:
  server:
    site:
      nginx_proxy_openstack_api_keystone:
        limit_conn_module:
          limit_conn_status: 429
          limit_conn:
            api_keystone_conn_zone:
              connections: 50
              enabled: true