Apache Module mod_proxy_hcheck

Available Languages: en

Description:	Dynamic health check of Balancer members (workers) for `mod_proxy`
Status:	Extension
Module Identifier:	proxy_hcheck_module
Source File:	mod_proxy_hcheck.c
Compatibility:	Available in Apache 2.5.0 and later

Summary

This module provides for dynamic health checking of balancer members (workers). This can be enabled on a worker-by-worker basis. The health check is done independently of the actual reverse proxy requests.

This module requires the service of mod_watchdog.

Parameters

The health check mechanism is enabled via the use of additional BalancerMember parameters, which are configured in the standard way via ProxyPass:

Parameter Default Description

hcmethod

None

No dynamic health check performed. Choices are:

Method	Description
None	No dynamic health checking done
TCP	Check that a socket to the backend can be created: e.g. "are you up"
OPTIONS	Send an `HTTP OPTIONS` request to the backend
HEAD	Send an `HTTP HEAD` request to the backend
GET	Send an `HTTP GET` request to the backend
CPING	AJP only Do `CPING/CPONG` check
PROVIDER	Name of `provider` to be used to check health

hcpasses 1 Number of successful health check tests before worker is re-enabled

hcfails 1 Number of failed health check tests before worker is disabled

hcinterval 30 Period of health checks in seconds (e.g. performed every 30 seconds)

hcuri Additional URI to be appended to the worker URL for the health check.

hctemplate Name of template, created via ProxyHCTemplate to use for setting health check parameters for this worker

Directives

ProxyHCTemplate

ProxyHCTemplate Directive

Description:	Creates a named template for setting various health check parameters
Syntax:	`ProxyHCTemplate name parameter=setting <...>`
Context:	server config, virtual host
Status:	Extension
Module:	mod_proxy_hcheck

The ProxyHCTemplate directive allows for creating a named set (template) of health check parameters that can then be assigned to balancer members via the hctemplate parameter

ProxyHCTemplate

ProxyHCTemplate tcp5 hcmethod=tcp hcinterval=5
ProxyPass "/apps"     "http://backend.example.com/" hctemplate=tcp5