Upgrading Cluster Nodes

Windows Server 2003 Cluster server is compatible with previous versions of Microsoft Cluster Service and can accommodate node operating system upgrades. Windows NT 4.0 clusters must be taken offline before upgrading to Windows Server 2003 clusters, whereas Windows 2000 clusters can be upgraded to Windows Server 2003 while online, utilizing the rolling upgrade method. Before a rolling upgrade can be performed, each resource in the cluster must be checked to see whether it can be upgraded during a rolling upgrade.

Note

Resources that do not allow rolling upgrades are IIS, FTP, DHCP, WINS, SMTP, and NNTP services, just to name a few. For detailed instruction on how to upgrade clusters containing these resources, refer to the Help and Support in the Windows Server 2003 operating system and search for "resource behavior during rolling upgrades" and "last node rolling upgrades."

Rolling Upgrades

A rolling upgrade allows a single cluster node to be taken offline for an operating system upgrade while the other nodes in the cluster function on the original OS version. On a standalone server, this is referred to as an inplace upgrade. When the upgraded node is back online with the new operating system, the Cluster server is already installed and configured. Cluster groups running on the other nodes can then be moved to the upgraded node, thus enabling administrators to upgrade the remaining nodes in the cluster.

Before attempting a rolling upgrade, the cluster administrator must research all the applications and resources in the cluster to ensure they can be supported during a rolling upgrade. If such an upgrade is not an option, the cluster nodes can be upgraded using the last node rolling upgrade method.

Last Node Rolling Upgrade

The last node rolling upgrade is a process created to upgrade clusters that contain resources that are unsupported during standard rolling upgrades. In this type of upgrade, the administrator moves all the groups containing resources that are unsupported in a standard rolling upgrade to a single cluster node. Then she upgrades all other nodes in the cluster. After all the other nodes are upgraded, she moves the groups with the unsupported resources to the upgraded nodes. Then the administrator performs an operating system upgrade on the last node and redistributes all the cluster groups as necessary.