To obtain a basic understanding of Application Center, you may first want to review the AC Pre-Flight Checklist (AC_PreFlightCheck.doc). This document is located in the Support folder on the Application Center CD-ROM. Additionally, you can download the checklist. To download the checklist, visit the following Microsoft Web site:

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This article includes important information about the following topics:

•	Installation
•	Microsoft SQL Server Desktop Engine
•	Cluster configuration and networking
•	Request forwarding
•	Network Load Balancing
•	Replication
•	Component Load Balancing
•	Health Monitor
•	Application Center 2000 Resource Kit
•	DebugView instructions

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Installation

The Application Center server component and the Application Center client are supported on Microsoft Windows 2000 Server Service Pack 4 (SP4), on Windows Server 2003, on Windows Server 2003 Service Pack 1 (SP1), and on Windows Server 2003 R2. Application Center is not supported on 64-bit operating systems. The Application Center client is also supported on Windows 2000 and on Windows XP Professional.

For more information about supported configurations for Application Center, visit the following Microsoft Web site: Application Center 2000 Service Pack 2 (SP2) is an integrated build of the full product. To download Application Center 2000 SP2, visit the following Microsoft Web site:To install Application Center 2000 SP2, you must have a valid license and a valid product ID (PID) key or CD key for Application Center 2000. If the key is lost, you must obtain a replacement key from the vendor who sold you the product.

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Internet Information Services (IIS) must be installed on the computer before you can install Application Center. You can install Application Center by running the Setup.exe file or by running the Setup.hta file. We recommend that you run the Setup.hta file to install Application Center. The Setup.hta file checks for prerequisites and creates a setup log in the Winnt folder or in the Windows folder. This log file is named Ac_setup.log.

If an installation issue occurs, and the reason for the issue is not clear from the error message, check the Ac_setup.log file for more information. To do this, follow these steps:

1.	In a text editor such as Notepad, open the Ac_setup.log file.
2.	Search for the first instance of "return value 3." This entry indicates where the installation failed.
3.	Review the lines just before "return value 3" to determine the process that caused the installation to fail.

For more information about common installation issues, click the following article number to view the article in the Microsoft Knowledge Base:

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Microsoft SQL Server Desktop Engine

An installation issue may occur while Application Center is installing Microsoft SQL Server Desktop Engine (MSDE). MSDE is installed as part of the "Event and Performance logging" component installation process. The Ac_setup.log file may show a failure in the InstallSQLAgentSecurity process.

The MSDE installation process checks for certificates that are installed on the server. Some installed certificates can cause Application Center MSDE connection issues and installation issues. Typically, these issues occur on Windows Server 2003. However, these issues may occur on other operating systems.

To resolve these installation issues, set the following registry value for the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSAC\MSSQLServer\SuperSocketNetLib registry key: This registry value makes the MSDE installation process ignore the certificate check.

For more information about how to resolve MSDE connection issues and installation issues, click the following article number to view the article in the Microsoft Knowledge Base: When you install the "Event and Performance logging" component of Application Center, the Setup process installs a named instance of Microsoft SQL Server 2000 Service Pack 3a (SP3a). This named instance includes MSDE. Additionally, the Setup process always installs this named instance on the system drive. Current security updates are still available for SQL Server 2000 SP3a. You can apply the current security updates to this named instance. However, you cannot upgrade this named instance to SQL Server 2000 SP4. Additionally, we do not support using Application Center with other instances of SQL Server.

If you are installing Application Center on a computer that is running Windows Server 2003 SP1, you must apply the hotfix that is described in Microsoft Knowledge Base article 891330 on all servers. After you apply the hotfix, you must restart the servers. For more information, click the following article number to view the article in the Microsoft Knowledge Base: The "Event and Performance logging" component lets you view performance counters or events for the whole cluster or for individual member servers. You can find similar information in the Event logs and in Performance Monitor. All the servers in a cluster must have the "Event and Performance logging" component enabled, or they all must have it disabled. When the "Event and Performance logging" component is enabled, the component does not affect Application Center replication functionality. However, some users may not use this component. Other users may not want to keep up with SQL Server security updates. Therefore, these users may choose not to install SQL Server 2000 SP3a.

Note If you uninstall and then reinstall the "Event and Performance logging" component, you must first remove the member server from the cluster.

MSDE has a size limit of 2 gigabytes (GB). If the ACLog database is close to this limit, you may want to reduce the size of the ACLog database. The SQLAgent service maintains the ACLog database. Therefore, you must make sure that the SQLAgent service is always running. For more information, click the following article number to view the article in the Microsoft Knowledge Base: Application Center uses the AC Perflog Consumer COM+ application to connect to MSDE. This application enumerates all performance counters on the servers. To re-create the AC Perflog Consumer COM+ application, type the following commands at a command prompt. Press ENTER after each command. If you receive the error message that is mentioned in the following Microsoft Knowledge Base article, you can safely ignore it: You can resolve some other MSDE issues by disabling and then re-enabling Performance Counter logging. Performance Counter logging is located in the properties of the Events node. You can also try to resolve these issues by restarting the MSSQL$MSAC service and the SQLAgent$MSAC service.

You can find information about how to troubleshoot other installation issues by searching the Microsoft Knowledge Base. Search for both the name of the process that failed and the phrase "Application Center."

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Cluster configuration and networking

Application Center supports up to 12 member servers in one cluster. The first computer in a cluster is the controller. All servers in a cluster must be in the same domain or in the same workgroup. Additionally, we recommend that all servers in a cluster be on the same subnet. All servers in a cluster must be running the same operating system, service pack, hotfixes, and versions of the Microsoft .NET Framework. All servers must also have the same file structure. For example, if Windows, IIS, or Application Center is installed on drive C on one server, the same product must be installed on drive C on all the other servers in the cluster.

There are three types of clusters:

•	Web cluster: A Web cluster is a farm of Web servers that are running IIS. Additionally, these Web servers can be accessed by intranet clients or by Internet clients.
•	Routing cluster: A routing cluster is used to route requests from DCOM clients or from a Web cluster to a COM+ cluster.
•	COM+ cluster: A COM+ cluster uses Component Load Balancing to create instances of COM+ applications across the computers in the COM+ cluster. A COM+ cluster is also known as a Component Load Balancing Web farm.

Before you create a cluster, you must configure your IP address settings. Typically, the back-end network adapter has one dedicated IP address and one gateway. We do not recommend that you use crossover cables on the back-end network adapter. When a server becomes part of a cluster, Application Center will modify the Hosts file on the server. Application Center does this to make sure that the NetBIOS name of the server always resolves to the IP address of the back-end network adapter. For more information, click the following article number to view the article in the Microsoft Knowledge Base: The front-end, or load-balanced, network adapter has one dedicated IP address and at least one other IP address. The other IP address is listed under Advanced TCP/IP Properties. The IP address that is listed under Advanced TCP/IP Properties is the first virtual IP address. You do not have to add this virtual IP address on the member servers before you add the member servers to the cluster. Application Center automatically adds the virtual IP address when you add a member server to the cluster. All front-end network adapters must be connected to the same switch.

For more information, click the following article number to view the article in the Microsoft Knowledge Base: Note The Application Center cluster service does not start until you have created a cluster. Typically, you do not have to manually control the Application Center services. When you create a cluster, the Application Center services start and stop as required.

At some point, you may have to remove a member server from the cluster. After you remove the member server, we recommend that you open a Command Prompt window on the member server, and then run the ac cluster /clean command. This command removes any cluster settings that may remain on the member server.

You may receive error messages that resemble the following when you try to add a server to the cluster: In this case, run the ac cluster /clean command on the member that you are trying to add or to designate as the cluster controller.

If the cluster controller is down, and you have to designate a member server as the controller, you can run the ac cluster /setcontroller /force command on the member server that you want to make the cluster controller. If you want to change the dedicated IP address of any network adapters in the cluster, you must first remove the member server from the cluster.

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Request Forwarding

The Request Forwarding feature lets a client connect to a server by using a cookie. This behavior prevents any loss of session state. We do not recommend that you use the Request Forwarding feature on Windows Server 2003. The ISAPI extension for the Request Forwarding feature is RfFiltExt (RfFilExt.dll).

For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base:

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Network Load Balancing

The Network Load Balancing (NLB) component is included with Windows 2000 Advanced Server and with all version of Windows Server 2003. If you are running Windows 2000 Server, Application Center will enable the Network Load Balancing component. Application Center will configure the Network Load Balancing settings automatically when you create the cluster. If the Network Load Balancing component is already configured, you can use the existing settings. If you experience any issues when you use the existing settings, you may want to let Application Center configure the Network Load Balancing settings again.

The Network Load Balancing component must be installed on your front-end network adapter before you create a cluster. However, you may not have to enable the Network Load Balancing component. If the Network Load Balancing component is not installed on the front-end network adapter, you may receive the error message that is mentioned in the following Microsoft Knowledge Base article: When you create a cluster, you have the following load balancing options:

•	Network Load Balancing: Requires two network adapters for each server
•	Other Load Balancing: Uses hardware load balancers For more information, click the following article number to view the article in the Microsoft Knowledge Base: 315517 (http://kbalertz.com/Feedback.aspx?kbNumber=315517/) How to manage Internet Information Services Web IP bindings by using third-party load balancing devices
•	None: Used for staging servers or for staging clusters on which you do not want Application Center to replicate the IIS IP bindings

The Application Center GUI shows the load balancing status of each member server in the cluster. To best troubleshoot Network Load Balancing issues, run the WLBS display command at a command prompt. When all hosts in a cluster are converged, all servers are online and are serving content. For more information, click the following article number to view the article in the Microsoft Knowledge Base: A working Network Load Balancing cluster has the following WLBS output:

WLBS Cluster Control Utility V2.4. (c)
		  1997-2003 Microsoft Corporation Host 1 converged as DEFAULT with the following
		  host(s) as part of the cluster: 1, 2

If you run the WLBS display command, and the output says that the host is stopped, you can run the WLBS start command to start the host. If the host is always converging, you may want to update the network adapter drivers.

If you must add more virtual IP addresses, you can locate the properties of the cluster name, and then add the virtual IP addresses.

Network Load Balancing is not supported on Layer 3 switches. If you have issues with Network Load Balancing, verify the switch type. To resolve or to avoid switch issues, we recommend that you plug all front-end network adapters into a hub, and then plug the hub into the switch. For more information about other Network Load Balancing issues and switches, click the following article number to view the article in the Microsoft Knowledge Base:

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Replication

The main function of Application Center is replication. You can use Application Center to create content and to change IIS settings on the controller. Then you can replicate the changes automatically or manually to other member servers in the cluster.

An Application Center application is defined as a collection of resources. Typically, resources include one or more of the following:

•	Web sites
•	Virtual directories
•	File system paths
•	Registry keys
•	DSNs
•	.NET Framework assemblies
•	COM+ applications

When you install Application Center, Application Center creates an application for each Web site. This is the default behavior. Additionally, Application Center creates an All Sites application. The All Sites application contains the applications that Application Center creates for each Web site.

When you synchronize a cluster, you are replicating all the resources that are defined in your applications. Application Center can automatically synchronize all resources except COM+ applications. You must deploy COM+ applications because you must use Microsoft Windows Installer to install them. Additionally, you must restart IIS services and related COM+ processes on the computers to which you have deployed the COM+ applications. Other resources that Application Center can replicate automatically are as follows:

•	Site bindings, except when no load balancing is enabled
•	Certificates
•	Application mapping DLLs
•	ISAPI filters

If you are replicating access control lists (ACLs), use the guidelines that are described in the following Microsoft Knowledge Base article: If you are deploying without permissions, and the permissions are changed during deployment, apply the hotfix that is described in the following Microsoft Knowledge Base article: When you enable automatic updates in the cluster properties, Application Center keeps the cluster synchronized almost in real time. Application Center does this based on change notifications. This behavior is not always guaranteed because files may be in use. Additionally, the USN journal may be overwritten in environments in which many changes occur at the same time. By default, the periodic full synchronization runs every 60 minutes. This full synchronization replicates anything that the automatic updates may not have replicated.

If your configuration is not supported, based on the number of member servers and on content size, you may experience issues when Application Center performs automatic updates. You may be able to resolve these issues by restarting the synchronization service.

If nothing is being replicated or deployed, make sure that the Include this member in synchronizations option is selected in the properties of each member server.

You may also want to verify the permissions. For more information about which permissions to verify, click the following article number to view the article in the Microsoft Knowledge Base: If you run the IIS application pool under a domain account, you may experience problems when you run the Web site application. These problems may occur because permissions in the IIS metabase have been changed. For more information about how to resolve these problems, click the following article number to view the article in the Microsoft Knowledge Base: If other methods have not resolved the issues that you are experiencing, run DebugView at the same time on both the source server and the destination servers, and reproduce the issue. For more information about DebugView, see the "" section. When you are reproducing an issue such as a deployment failure that occurs between two servers, the easiest way to reproduce the issue is to deploy a folder that contains only one file.

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Component Load Balancing

If you have a cluster of Web servers that call many COM+ objects into memory, you can set up a separate COM+ cluster to create instances of those COM+ objects. This method helps prevent overloading of the actual Web servers. This COM+ cluster does not actually perform any Web site synchronization because only COM+ applications are deployed on this COM+ cluster.

On the Web cluster or on a routing cluster, you will list the names of the servers in the COM+ cluster. If you change this list, you must restart the Cluster service and the COM+ Component Load Balancing service on the Web cluster.

You will install COM+ applications on both the Web cluster and the COM+ cluster. These installations are identical, except that the Supports dynamic load balancing option is selected at the component level on the Web cluster. This configuration makes the Web cluster send the request to the Component Load Balancing servers for processing. If you change the setting of the Supports dynamic load balancing option, or if you change the routing list, you must restart the Cluster service and the COM+ Component Load Balancing service on the Web cluster.

If you experience issues when you deploy COM+ applications to the COM+ cluster, first try to export the COM+ application to a Windows Installer (.msi) file. Then, manually install the COM+ application on the COM+ cluster. Application Center typically uses Windows Installer files to deploy applications. If this method fails, the deployment will also fail.

You must have DCOM connectivity between the Web cluster and the COM+ cluster. If the DTCPing tool fails between the computers, troubleshoot the DCOM connectivity issue.

You can also run the ac cluster /listmembers command to verify that all the COM+ servers are online.

For information, and for sample components to test Component Load Balancing, see the Application Center Pre-flight Checklist. This checklist is located in the Support folder of the Application Center CD. For more information, visit the following Microsoft TechNet Web sites:

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Health Monitor

The Health Monitor tool is installed automatically when you install Application Center. You cannot separately install Health Monitor. However, if you want to remove Health Monitor, you must separately remove the tool. You can use Health Monitor to monitor for specific events, such as event log IDs, WMI events, and IIS response codes. If an event that you want to monitor occurs, Health Monitor performs the action that you specify for that event. For example, Health Monitor will run a script, create a batch file, send an e-mail message, bring a server online, or take a server offline. When you create a synchronized monitor, Application Center replicates the monitor to the other member servers in the cluster.

For Health Monitor, the most common installation issue occurs on computers that are running Windows Server 2003. If the installation process for Health Monitor fails, log on locally to the server, and then try to run the installation process again.

For more information about Health Monitor, visit the following Microsoft Web site:

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Resource Kit

The Microsoft Application Center 2000 Resource Kit is available in two formats. To view the Resource Kit online, visit the following Microsoft TechNet Web site:To download the Resource Kit in Microsoft Reader format, visit the following Microsoft Web site:

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DebugView instructions

DebugView is a Win32 application. You can use DebugView to capture a debug log during any Application Center process failure. This log is helpful when you contact Microsoft Application Center Support for help. For more information, and to obtain DebugView, visit the following Microsoft TechNet Web site:Note To troubleshoot deployment issues or synchronization issues, you must run DebugView on both the source servers and the destination servers at the same time.

To perform tracing by using DebugView, follow these steps:

1.	Turn on tracing in the registry. To do this, run the Traceoutput.reg file. This file is located in the Support folder on the Application Center 2000 CD. To obtain the most detailed output, set the DWORD value of the Level entry to 00000003. However, this setting affects performance the most. Therefore, if you want to continue tracing for an extended period, you may want to use level 2 (00000002) or level 1 (00000001) instead. Level 2 traces only errors and warnings. Level 1 traces only errors. You can set these values by running the Traceoutput.reg file. Or, you can follow these steps to set the values: a. In a text editor such as Notepad, paste the following text in a new file. [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\ACS] "AlwaysODS"=dword:00000001 "Level"=dword:00000003 "ControlFlags"=dword:00ffffff "Active"=dword:00000001 b. Save the file as TraceOutput.reg. c. Run the file that you created in step b.
2.	Stop and then restart all Application Center services including the COM+ Component Load Balancing service. The easiest way to do this is to restart the server. Or, you can manually restart each service.
3.	Start DebugView to capture the debug output. To do this, run the Debugview.exe file that you downloaded previously. Use DebugView to capture debug output: • When you run DebugView, it will immediately start capturing debug output. • On the Capture menu, make sure that Capture Win32 and Capture Global Win32 are selected.
4.	While DebugView is capturing the debug output, reproduce the issue that you are experiencing in Application Center. After all activity that is related to the issue has stopped, go to step 5.
5.	Stop capturing the debug output. To do this, follow these steps in DebugView: a. On the Capture menu, click to remove the check mark next to Capture Events. b. On the File menu, click Save As to save the output log.
6.	Send the output file to Microsoft Customer Support Services. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft Web site: http://support.microsoft.com/contactus/?ws=support (http://support.microsoft.com/contactus/?ws=support) Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

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