The High Availability (HA) feature of the LoadMaster guarantees the availability of your server farm. HA is achieved by a hot-standby/failover mechanism. Two identical LoadMaster units are integrated into the network as a HA pair. One machine serves as the active LoadMaster and the second one remains in a standby, idle state - always prepared to take over the activities from the active server. This pair appears as a single logical unit to the internet side and to the server farm side connections.

With a HA pair, each network interface has an individual IP address and one shared IP address which is shared with the partner unit. The shared IP address is identical for both LoadMaster appliances, though it is associated with only the active LoadMaster at any given time.
Note: A shared IP address must be added to all production interfaces.
Note: HA in the LoadMaster for cloud products works differently to that of a regular LoadMaster. For more information and instructions on how to configure HA on the LoadMaster for cloud products, refer to the relevant document in the Cloud LoadMaster Installation Guides.

You must have three IP addresses available for HA configuration purposes. These are required for the:

  • Active unit
  • Standby unit
  • Shared interface
Unit 1 Unit 2
Interface address 192.168.15.110 192.168.15.111
Partner address 192.168.15.111 192.168.15.110
Shared IP address 192.168.15.112 192.168.15.112

For a one-armed configuration, only one interface is configured. Two individual Virtual IP (VIP) addresses are set on each LoadMaster unit as their physical IP address; one address for HA-1 and the other for HA-2. The third IP address is set for the shared IP address which is for the Web User Interface (WUI) management page and routing. Additional addresses are needed if there is a need to set up the HA pair as a two-arm configuration and configure more interfaces. Each additional interface configured requires three free IP addresses per interface.

Document Purpose

This document describes the HA feature in the LoadMaster and provides step-by-step instructions on how to configure HA (active/standby).

Note: If you want to have multiple units in an active/active configuration, review the LoadMaster Clustering Feature Description.