Upgrading an Existing Network Load Balancing Cluster

Applies To: Windows Server 2008, Windows Server 2008 R2 with SP1, Windows Server 2012

You can upgrade an existing Network Load Balancing (NLB) cluster to Windows Server 2008, Windows Server 2008 R2, or Windows Server 2012 by taking the entire cluster offline and upgrading all the hosts, or you can leave the NLB cluster online and perform a rolling upgrade. A rolling upgrade entails taking individual cluster hosts offline one at a time, upgrading each host, and returning the host to the cluster. You continue upgrading individual cluster hosts until the entire cluster is upgraded. A rolling upgrade allows the cluster to continue running during the upgrade.


The NLB functionality in Windows Server 2012 is generally the same as in Windows Server 2008 R2. However, some task details are changed in Windows Server 2012. For information on new ways to do tasks, see Common Management Tasks and Navigation.

The decision to use rolling upgrades is based on the applications and services running on your existing cluster. If the applications and services support rolling upgrades, then perform a rolling upgrade on the existing cluster. Otherwise, perform the upgrade process recommended for the applications and services running on the cluster.

This section covers the following areas:

Preparing to upgrade the Network Load Balancing cluster

Upgrading the Network Load Balancing cluster