Configuring for high availability and collocation when using Load Balancer on Microsoft Windows operating systems

Resolving The Problem

When you use collocation with high availability, you need an additional IP address, which is a sort of dummy IP address, that can be added to the loopback adapter on the Windows operating system. You need to install the loopback adapter on both the primary and backup machines. Follow the steps that are outlined in the Load Balancer Administration Guide for installing the loopback device on Windows systems.

When using high availability, you do not need to alias to and from the loopback device in the go scripts unless you have a collocated server for that machine. If you are using a configuration that has a collocated server on one Load Balancer machine but not on the other machine, you only need to alias to and from the loopback device on the Load Balancer machine that has the collocated server.

When the steps tell you to add the cluster IP address to the loopback, you must add a dummy IP address; not the cluster address. The reason for this change is that the high availability go scripts for Windows systems need to delete and add the cluster address to the loopback device, which depends upon whether the Load Balancer system is in an active or standby mode.

Windows operating systems do not allow scripts to remove the last configured IP address from the loopback device because the loopback device does not function in DHCP mode. The dummy address allows Load Balancer to remove its cluster address at any time. The dummy IP address is not used for any type of traffic and can be used on both the active and standby systems.

Update and move the Load Balancer go scripts on both the active and standby systems and then start Dispatcher. The cluster address is added and removed from both the network interface and the loopback device at the appropriate times.