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Element health checks, Introduction, Configuring element-action expressions – Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) User Manual

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Brocade Virtual ADX Server Load Balancing Guide

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Element health checks

4

Element health checks

Introduction

The Brocade Virtual ADX allows the creation of a health check that is customized for a given
application server. Such definition is also known as element health check. You can specify the
health check frequency, the number of retrials, and the number of other parameters for server
health check.

Configuring element-action expressions

An element-action expression contains the IP address, protocol (TCP or UDP), and application port
number for an application on an individual real server. If the Brocade Virtual ADX allows you to
customize Layer 7 information for the application, then the element-action expression also can
contain the customized Layer 7 information.

You can also change the following parameters for an application port when configuring an
element-action expression:

Health check type – For application types that are well-known to the Brocade Virtual ADX, you
can specify whether you want to use the Layer 4 health check or the Layer 7 health check for
the port. By default, the Brocade Virtual ADX uses the Layer 7 health check if the port one of
the types that are well known to the Brocade Virtual ADX.

Health check interval – By default, the Brocade Virtual ADX performs the health checks every 5
seconds. You can change the interval to a value from 2 through 120 seconds.

Health retries – By default, if a reply to a health check is not received, the Brocade Virtual ADX
will attempt the health check two more times before concluding that the application has failed
the health check. You can change the number of retries to a value from 1 through 5 retries.

Health check state – By default, the health check is enabled as soon as you configure it. You
can disable or re-enable the health check from within the element-action expression for the
check.

Specifying the IP address and application port parameters

To configure an element-action expression, enter commands such as the following. The commands
in these examples specify the IPv4 or IPv6 address of the real server and the application port on
the server.

Example for IPv4

Virtual ADX(config)#healthck check1 tcp

Virtual ADX(config-hc-check1)#dest-ip 10.10.10.50

Virtual ADX(config-hc-check1)#port http

Example for IPv6

Virtual ADX(config)#healthck check-v6 tcp

Virtual ADX(config-hc-check-v6)#dest-ip 2001:db8:2000::1

Virtual ADX(config-hc-check-v6)#port http