Limitations

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

A rolling upgrade is not as disruptive as a regular upgrade, but you should bear in mind that it requires the applications to be moved between nodes and therefore does cause some minimal disruption in services. When an application is moved from one node to another, it must be stopped. Once the application is stopped, Cluster service moves all the resources the application uses, such as disks, Internet Protocol (IP) addresses or network names to another node, and restarts the application on another node. Any sessions between clients and the server application are cancelled during this process; database transactions are aborted and file handles are invalidated. Client applications can retry and eventually reconnect and recover once the server application is restarted on the second node. While the impact may be minimal, it should not be ignored.

The availability of a two-node cluster while one node is being upgraded is limited. Any failure of the second node while the other node is being upgraded will cause the cluster to fail.

During a rolling upgrade of a 2-node cluster, all resource groups are moved to one node. In a cluster where resources are distributed among all nodes in the cluster, this means that the node hosting all resources can run at maximum capacity while the other node is being upgraded. This can affect the application response time.

For a rolling upgrade of Windows 2000 Datacenter Server cluster with more than 2 nodes, a user will have different options to move the resources from the node that is upgrade to other nodes. Depending on the configuration and node capacity, you may want to move resources to a node that can handle the additional load from the node that is being upgraded. You can also distribute the resources from upgraded node to different nodes to reduce the performance impact. Chart out which resources will be moved to which node/nodes during each node upgrade before proceeding with rolling upgrade.

It is critical that you plan rolling upgrade of your cluster up front. You may have to plan differently if you decide to run mixed-version cluster for couple of days before upgrading the remaining downlevel nodes to Windows Server 2003. Please list out services and applications that you run on the cluster. Figure out what services or applications can be failed over (and failed back) to Windows Server 2003 from Windows 2000 operating system and vice versa. This information will be useful if you have to failover or move resources between nodes that are running different version of operating system. Check application documentation for the mixed-version cluster support requirements.

Cluster service guarantees that an up-level node can always join a cluster formed by a down-level node. It also guarantees that resources can fail over and fail back to and from a down-level node. However, it does not guarantee that applications can also support rolling upgrades of the operating system. Table 1 below summarizes the behavior of cluster-aware resources supported by Cluster service.

Table 1 Resources supported/not supported during rolling upgrades.

Resource	Note
File Share	Supported during rolling upgrades.
IP Address	Supported during rolling upgrades.
Network Name	Supported during rolling upgrades.
Physical Disk	Supported during rolling upgrades.
WINS	WINS is not supported during rolling upgrades. You must follow the below instructions during rolling upgrade for WINS resource. Confirm that your systems are running Windows 2000 and right Service packs if there is any. Move WINS resource to a single node by double clicking the Groups folder in Cluster Administrator's console tree. Click the group that contains the resource and then in the File menu, click Move Group. Upgrade the operating system on each of the nodes that is not hosting the WINS resource moved in the previous step. Move the WINS resource that you moved in the earlier steps from the node that has not been upgraded to one of the newly upgraded nodes. Notes: After the upgrade, the WINS resource can not failback to the Windows 2000 node. Following the procedure as described above will typically give you the highest availability of the resources that do not support rolling upgrades.
DHCP	DHCP is not supported during rolling upgrades. You must follow the below instructions during rolling upgrade for DHCP resource. Confirm that your systems are running Windows 2000 and right Service packs if there is any. Move DHCP resource to a single node by double clicking the Groups folder in Cluster Administrator's console tree. Click the group that contains the resource and then in the File menu, click Move Group. Upgrade the operating system on each of the nodes that is not hosting the DHCP resource moved in the previous step. Move the DHCP resource that you moved in the earlier steps from the node that has not been upgraded to one of the newly upgraded nodes. Notes: After the upgrade, the DHCP resource can not failback to the Windows 2000 node. Following the procedure as described above will typically give you the highest availability of the resources that do not support rolling upgrades.
Distributed Transaction Coordinator	Supported during rolling upgrades. However, be aware that you should not create or delete the MSDTC resource while you are operating as a mixed mode (mixed version) cluster. You should instead create the MSDTC resource before starting the upgrade on any node, or wait until the upgrade is complete on all nodes.
Internet Information Services	See section Rolling upgrade Windows 2000 Internet Information Services to Windows Server 2003.
NNTP Service	NNTP Service Instance is not supported in Windows Server 2003 Enterprise Edition, therefore you must remove any NNTP Service Instance resources prior to upgrading.
SMTP Service	SMTP Service is not supported in Windows Server 2003 Enterprise Edition, therefore you must remove any SMTP Service resources prior to upgrading. Note This refers only to the built-in clustering resource for Windows SMTP. SMTP resources based on the Exchange 2003 resource DLL (exres.dll) are not affected by this upgrade limitation and should not be removed.
Time Service	Time Service is not supported in Windows Server 2003 Enterprise Edition, therefore you must remove any Time Service resources prior to upgrading.
Local Quorum	Supported during rolling upgrade.
Message Queuing	Primary Enterprise Services, Primary Site Services, and Backup Site Services are not supported during rolling upgrades. All other Message Queuing Services configurations are supported during rolling upgrades. Take all of the MSMQ cluster resources offline. For each MSMQ resource, take the Network Name resource that depends on it offline also. Upgrade all of the nodes from Windows 2000 to Windows Server 2003 Enterprise Edition. Bring the Network Name resources back online. Ensure that the Distributed Transaction Coordinator (DTC) resource is online, then bring the MSMQ resources online.
Print Spooler	The only Print Spooler resources supported during a rolling upgrade are those on line printer remote (LPR) ports. For more information, refer to Print documentation on Windows Server 2003 Enterprise Edition CD or Windows Server 2003 Enterprise Edition resource kit.
Other resource types	See the product documentation supplied with the application or resource.

Before performing a rolling upgrade, identify the resources on your cluster that do not support rolling upgrades. This will help in determining which upgrade procedure you should use.

Internet Information Services Rolling upgrade

Windows Server 2003 provides a script that allows you to upgrade IIS. You can choose to either use the script or do the upgrade manually. In Windows Server 2003 operating system IIS is managed in a cluster using generic script resource.

Below are two methods by which you can upgrade a cluster that has IIS installed.

1. To upgrade from Windows 2000 on a cluster containing IIS using the provided script.

   1. If you do not already have a Distributed Transaction Coordinator (DTC) resource on the cluster that you are upgrading, create a DTC resource on this cluster.

   2. Upgrade or perform rolling upgrade (whichever is suitable for your needs) all nodes except the node containing the IIS instance resource from Windows 2000 to Windows Server 2003 Enterprise Edition.

   3. On an upgraded node, from command prompt navigate to the %systemroot%\system32\inetsrv directory and run

      iis_switch cluster name [group name]

      Value	Description
      Cluster name	Cluster name or virtual server name that is hosted on an upgraded node.
      Group name	By default the script will upgrade all IIS web and FTP resources in the cluster. A user has the option to specify a particular resource group also.

      Note

      The script will bring the group with the newly created Generic Script resource online. However the process of bringing resource online after upgrade will fail if all resources in the group were offline or were only partially online at the time of script run.

      The script will not upgrade IIS resources that are in the cluster group.

      Once the script completes, using IIS, start the web site on the upgraded node. At this stage IIS can only be hosted on a Server 2003 nodes as it uses generic script that does not exist in Windows 2000 server cluster. Upgrade the final node now.

2. To upgrade from Windows 2000 on a cluster containing IIS manually.

   1. If you do not already have a Distributed Transaction Coordinator (DTC) resource on the cluster that you are upgrading, create a DTC resource on this cluster.

   2. Upgrade or perform rolling upgrade (whichever is suitable for your needs) all nodes except the node containing the IIS instance resource from Windows 2000 to Windows Server 2003 Enterprise Edition. Bring the IIS instance resource offline on Windows 2000 node after noting the dependencies of the IIS instance resource. You should note resources that depend on the IIS resource and also note what resources IIS itself is dependent on.

   3. Delete the IIS resource after removing any dependencies on the IIS instance resource.

   4. Move the group to a Windows Server 2003 Enterprise Edition node and create a Generic Script resource.

      Note

      From your notes of Step c, recreate the dependencies of the Generic Script resource identical to those of the now deleted IIS resource. You should make everything that was dependent on the IIS resource dependent instead on the Generic Script resource. You should also make the Generic Script resource dependent on everything that IIS was dependent on. Make sure the upgraded resource is the owner of the Generic Script Resource for IIS.

   5. Bring the group containing the new Generic Script resource online.

   6. Using IIS, start the web site on the upgraded node.

   7. Upgrade the final node.

Application Considerations

As stated earlier, Cluster service does not guarantee that applications can support rolling upgrades. Applications can, however, support rolling upgrades provided that they do not:

• Store program files on the clustered disk.

• Change the resource DLL name or location.

• Delete application registry keys either in the system registry or in the cluster configuration database.

• Change application on-disk data structures.

An application that does any of the above will not support rolling upgrades.