Replication and Clustering in IIS

Internet Information Server is designed to be be easily and effectively integrated with clustering applications such as Microsoft® Cluster Server. Also, IIS provides a commandline utility for replicating the IIS metabase from one server node to others. This section explains how to use the utility and introduces some of the features a few of the applications available for replication and clustering needs.

Software that Provides Clustering and Replication

You can replicate content and / or configuration settings for Web or FTP servers by either of the following:

Microsoft Cluster Server (MSCS) is the clustering solution for computers running Windows NT Server. MSCS version 1.0 supports clusters of two specially linked servers running Windows NT Server. If one server in a cluster fails or is taken offline, the other server takes over the failed server's operations. If you wish to use IIS with MSCS, first install Windows NT Server 4.0 Enterprise. Then install Microsoft Cluster Server 1.0. Finally, install IIS 4.0 as described below.
The Microsoft Content Replication System (CRS), part of Microsoft Site Server. CRS makes it easy to replicate content across multiple Web and FTP servers.
An IIS utility called Iissync.exe, which replicates IIS configuration settings, so that you can easily maintain servers with exactly the same settings. Such replication is necessary for servers that are to work together in load balancing or clustering scenarios.

To replicate configuration settings from one Web or FTP server to another:

On the source (master) server, at the command prompt, navigate to the utility's folder, %SystemRoot%\system32\inetsrv.
Next replicate the configuration settings by typing: iissync destination, where destination is the computer name of the server on which you want to replicate configuration settings.
To replicate configuration settings from the master computer to several other computers simultaneously, simply list the names, separated by spaces, after the Iissync command. For example iissync clusternode_2 clusternode_3 ... etc.

Important SSL (Secured Sockets Layer) keys will be replicated by the Iissync.exe utility. This include the default key. Because such keys may be specific to a server (keys contain the host name of the local HTTP server) administrators should manually back up SSL keys before replication because replication may overwrite them. For instruction about how you can backup these keys see Creating and Managing Server Key Pairs.

Note If the destination server already contains an IP address bound with a host name and port, that IP address is not changed when the configuration is copied.

Note Clusters must already exist for this utility to function. If the computer name used is incorrect, an error is returned and replication does not take place.

Clustering Web or FTP Servers

When setting up clustering for Web or FTP servers, there are two resources you must specify as clustered resources: the IIS Web or FTP site and an IP address, on which the IIS Web or FTP site depends. The following procedure describes the steps to take when setting up clustering with IIS. For more detailed information see the documentation for Cluster Server.

To add an IIS resource using the Cluster Administrator

In the Cluster Administrator, select the group into which you want to add the new resource. This is typically the Cluster Group for the first IIS resource.
On the File menu select New and then Resource. In the dialog box, enter the name and description for the new resource and select the resource type IIS Server Instance from the drop-down list box. Click Next.
From the selection field, select the nodes in the cluster on which you want the resource to be available. By default all the available nodes are selected. Click Next.
Select a dependency for the new resource from the left hand pane. This will typically be the Cluster IP Address. You can select multiple dependencies. Click Add to select these dependencies. Click Next.
Select either FTP or WWW. Select a server from the drop-down list. Click OK.

To set up clustering on two Web or FTP servers

Install Microsoft Cluster Server on both servers.
Install IIS on both servers.
Use the Cluster Service Administration user interface to create a second IP address resource on node A in a new group (Group 2).

Note Multiple IP addresses will be managed by the cluster. Each node can host multiple IP addresses at the same time, and each one can be failed-over independently. If only a single Web or FTP site is being clustered, you can set its IP address to "Unassigned". However, if multiple sites are being clustered, then you must explicitly assign an IP address to each clustered site.

Use Internet Service Manager to create and assign the second Web site to the second IP address by opening the property sheets for the Web site and entering the IP address.
Make sure that all anonymous user names and passwords used in the Web site configurations are usable on all nodes of the cluster. All virtual root paths should either point to a shared drive (that is, a UNC or cluster hard disk) or to identical local disks (that is, the same drive letters and directory structures on all nodes in cluster).
Add all Web Sites as cluster nodes using Cluster Service Administration user interface. The first Web Site should be created in the Cluster Group and made dependent on IP1 (cluster IP address); the second Web Site should be created in Group 2 and made dependent on IP2.
Manually backup SSL keys, because replication will overwrite them with the ones that are installed on the source system (node A).
Delete all non-cluster Web sites on target node (B) by using Internet Service Manager. This is to ensure that replications will correctly create cluster configuration on the target (node B), because replication does not overwrite an existing server IP address assignment.
Replicate the configuration settings from node A to node B by using the Iissync.exe utility. You can now move Web sites from one node to another by using the Move Group command of the Cluster Service Administration user interface.

Important You can start and stop Web and FTP sites on a non-clustered computer using Internet Service Manager. However, use the Cluster Server administration user interface to start and stop Web or FTP sites on a clustered computer. You can still use Internet Service Manager to set Web or FTP site properties.