ngx_http_healthcheck_module

This module is not distributed with the Nginx source. Installation instructions are below. You can get the module here

Healthcheck plugin for nginx. It polls backends and if they respond with HTTP 200 + an optional request body, they are marked good. Otherwise, they are marked bad.

Note this also gives you access to a health status page that lets you see how well your healthcheck are doing.

The docs on this wiki can get out of date. For the authoritative information, please see the README file inside the plugin's git repository.

Directives

healthcheck_enabled

syntax healthcheck_enabled

context upstream

Enables health checking of an upstream

healthcheck_delay

syntax healthcheck_delay

default 10000

context upstream

Delay in msec between healthchecks for a single peer.

healthcheck_timeout

syntax healthcheck_timeout

default 2000

context upstream

How long in msec a healthcheck is allowed to take place

healthcheck_failcount

syntax healthcheck_failcount

default 2

context upstream

Number of healthchecks good or bad in a row it takes to switch from down to up and back. Good to prevent flapping

healthcheck_send

syntax healthcheck_send

default <empty>

context upstream

Required directive. What to send for the healthcheck. Each argument is appended by \r\n and the entire thing is suffixed with another \r\n. For example:

  healthcheck_send 'GET /health HTTP/1.0'
   'Host: www.yourhost.com';

Note that you probably want to end your health check with some directive that closes the connection, like Connection: close.

healthcheck_expected

syntax healthcheck_expected

default <UNSET>

context upstream

What to expect in the HTTP BODY, (meaning not the headers), in a correct response. If unset, just a HTTP 200 status code is required for a peer

healthcheck_buffer

syntax healthcheck_buffer

default 1000

context upstream

How big a buffer to use for the health check. Remember to include headers PLUS body, not just body.

healthcheck_status

syntax healthcheck_status

context upstream

When inside a /location block, replaced the HTTP body with backend health status. Use similarly to the stub_status module.

Installation

This module is not distributed with the Nginx source. You can download the module from here. Read the installation instructions inside the README file.

Bugs

Please report bugs to here