Module 12: Microsoft Windows 2000 Clustering

Overview Application of Clustering Technology Testing Tools

Many clustering solutions will support multitiered application architecture, which requires improvement of availability and scalability in each of the tiers. You must decide which clustering technology will provide the best benefit within each tier. Microsoft® Cluster service and Network Load Balancing (NLB) technologies permit significant improvements of scalability and availability for applications and services. Application environments that are developed by using the Microsoft Windows® DNA and.NET strategies rely on these technologies. Enterprise developers utilizing the n -tier computing model of Microsoft’s Windows DNA strategy are able to reduce their deployment and maintenance costs.

Microsoft’s current.NET Enterprise Servers are built on and extend the Windows DNA foundation and make it possible for companies to create scalable Web-based solutions. You can leverage these Web-based solutions to create the next generation of applications, which are based on the.NET strategies. After completing this module, you will be able to: Describe technologies or scenarios where you can use clustering solutions to improve availability, scalability, and reliability. Identify the tools that are used to test client to Internet Information Services (IIS) 5.0 performance.

Which Clustering Technology Should You Use for Your Application? ClusterServiceClusterService Networking Load Balancing BalancingBenefitsBenefits Application of Clustering Technology Web Server Farm Terminal Services File/Print Servers File/Print Servers Database/ Messaging Quickly expand your capacity Minimize site downtime Quickly expand your capacity Minimize site downtime Quickly expand your capacity Minimize effects of server failures Quickly expand your capacity Minimize effects of server failures Minimize service downtime Ensure data consistency after failover Minimize service downtime Ensure data consistency after failover Minimize application downtime Ensure data consistency after failover Minimize application downtime Ensure data consistency after failover E-Commerce Sites E-Commerce Sites Quickly expand your capacity Minimize effects of server/app. downtime Quickly expand your capacity Minimize effects of server/app. downtime ScenarioScenario TechnologyTechnology      

Depending on the applications and services that are being provided, you can use Network Load Balancing or Microsoft Cluster service to improve availability, scalability, and reliability. Cluster service configurations can provide higher performance but typically are only used to increase availability by providing failover support for applications and services. You can configure Network Load Balancing to provide improvements in performance and availability.

 Web Server Farms In a Web farm, you use Network Load Balancing with two or more servers to host the same site. Network Load Balancing becomes necessary when a single server: Cannot provide adequate performance and you must employ a scale out strategy to service a larger number of users. Cannot provide the required availability and requires a failover or a redundancy strategy. A single high availability Web site can use Cluster service to improve availability, but Cluster service will not provide scale out support, only scale up support. You will typically not use Cluster service where you require performance improvements and fault tolerance.

 Terminal Services When providing Terminal Services for a large number of clients, you can use Network Load Balancing to simplify client connections. You can use Network Load Balancing to distribute a large number of clients running Terminal Services among a group of servers running Terminal Services. Multiple servers become necessary when a single server: Cannot provide the required level of client performance. Cannot support the required number of client connections and multiple servers will complicate client configurations (Connection Manager Profiles). Cannot provide the required level of availability or fault tolerance.

 File and Print Servers When using the Microsoft network commands (such as net use) or when mapping in remote shares, you can access clustered servers as a whole by using a single network basic input/output system (NetBIOS) computer name. Clustering service clusters become necessary when a single server: Cannot provide the required level of availability. Cannot ensure data consistency after a failure occurs.

 Database and Messaging Servers When using single point of access applications, such as Microsoft SQL Server™ and Microsoft Exchange Server, you can use Clustering service to provide failover support. These applications can tolerate a failed application or computer providing that data consistency can be ensured for the data store. Cluster service clusters become necessary when a single server: Cannot provide the required level of availability. Cannot ensure data consistency after a failure occurs.

 E-Commerce Sites In an e-commerce environment, you can design solutions with a Business-to-Business (B2B) or Business-to-Consumer (B2C) focus. In either solution, the design will typically be based on an n -tier architecture by using Web-based client application services, and component-based business logic and data services, including databases. E-commerce solutions are likely to include Network Load Balancing and Microsoft Cluster service within the design. Component Load Balancing may be included in solutions requiring extensive business logic. E-commerce solutions are typically based on several computers, with Web services using Network Load Balancing for high availability, fault tolerance, and scalability. Cluster service provides failover support for single point of access applications, such as SQL Server.

Testing Tools Web Capacity Analysis Tool Web Application Stress Tool

The following tools are available to test client to IIS 5.0 performance. The tools simulate the activity of a large number of clients by asynchronously accessing a Web site consisting of Hypertext Markup Language (HTML) or Active Server Pages (ASP)-based pages.

 Web Capacity Analysis Tool The Microsoft Web Capacity Analysis Tool (WCAT) runs simulated workloads on client-server configurations. Using WCAT, you can test how your Internet Information Services and network configuration respond to a variety of different client requests for content, data, or HTML pages. You can use the results of these tests to determine the optimal server and network configuration for your computer. WCAT is specially designed to evaluate how Internet servers running Microsoft Windows 2000 (or Microsoft Windows NT®) and Internet Information Services respond to various client workload simulations.

The WCAT provides the following features: Prepared, ready-to-run workload simulations to test the most common aspects of server performance. Prepared workload simulations to test the response of your server to Active Server Pages (ASP). Prepared workload simulations to test the response of your server to Secure Sockets Layer (SSL) version 2.0, version 3.0 and Private Communication Technology (PCT) version 1.0 encryption. Prepared workload simulations to test the response of your Hypertext Transfer Protocol (HTTP) service to HTTP Keep-Alives. The ability to create and run your own client-server workload simulations. The ability to use cookies, a technology that some Web sites support. Cookies are a means by which, under the HTTP protocol, a server or script can maintain state information on the client workstation. The ability to test servers that are connected to more than one network.

 Web Application Stress Tool The Microsoft Web Application Stress tool is designed to realistically simulate multiple browsers that are requesting pages from a Web site. You can use this tool to gather performance and stability information about your Web application. This tool simulates a large number of requests with a relatively small number of client machines. The goal is to create an environment that is as close to production as possible so that you can find and eliminate problems in the Web application prior to deployment.

Discussion: Implementing Clustering Technologies Single subnet No routers No Internet access ethernet Web Host 1 Web Host 1 SQL Server Database Web Host 2 Web Host 2 Web Host 3 Web Host 3 Web Host 6 Web Host 6 Network Load Balancing Component Load Balancing Network Load Balancing Component Load Balancing 2-node Cluster Service Clients

Using a site that will benefit from the use of both Network Load Balancing and Microsoft Cluster service, you will complete a lab that is designed to demonstrate your understanding of how you can implement these clustering technologies in a real world scenario. The lab scenario addresses the needs of a small engineering firm that has implemented Microsoft Windows 2000 Advanced Server. The current system configuration is one computer running IIS 5.0 and a second computer with a database running SQL Server. The computer running IIS 5.0 hosts the Web site and the SQL Server database stores the client state information and the Web site query data.

The engineering firm has implemented the Web site application as follows: Available to clients on an intranet, but not on the Internet Provides engineering information with many large.gif files as drawings The parts data for each drawing is stored in the database Users make no modifications to the drawings New drawings are released and copied over to the Web site from an engineering workstation as they are created Client configuration is a single subnet and all clients have been issued static Internet Protocol (IP) addresses Simple hubs service the whole subnet

 Current Web Site Problems With a single Web server, the client response times have been unacceptable. In a recent computer failure, the Web site was unavailable for 20 hours. In the last few days a memory fault caused SQL Server to stop responding causing an eight-hour server downtime. The Information Technology (IT) manager, fearing for his job, wants to ensure that the site will be fault tolerant, and is willing to spend some money to rectify the situation. He hires you to fix the problem.

You have completed an analysis of the system and you have decided that you can fix the problem by deploying Network Load Balancing on the front-end, which is supporting six identical Web sites. You will replace the database computer running SQL Server with two computers, with a shared external small computer system interface (SCSI) disk array, and configure it with Microsoft Cluster service to provide failover capability for the SQL Server database. The IT manager wants a demonstration of the technology that will be used to provide the solution. You have decided to demonstrate the use of Network Load Balancing and Cluster service by using the Northwind database that is supplied with Microsoft SQL Server. The sample database provides a Web site for accessing the data that is stored in SQL Server, and you will use this Web site to demonstrate the fault tolerance of Network Load Balancing and failover capability of Cluster service.

The supplier configured the Cluster service cluster for you and has copied the database to the cluster. You have six client computers that are available for testing and the six computers for the Network Load Balancing cluster are almost configured.

You need to do the following: Configure two NLB clusters. Copy the new Web site onto each cluster host. Install a performance tool and try to test the Web site. Run the test software and acquire the test results. Discuss the test results with your IT manager. Demonstrate the new fault tolerance of the site by removing and adding servers to the Network Load Balancing cluster. Demonstrate the failover of SQL Server on the server cluster.

Lab A: Implementing an N-Tiered Clustering Solution

In this lab you will work with other students to build the classroom computers into an n-tiered site based on Windows 2000 Network Load Balancing and Cluster service technology. The site will consist of two NLB clusters providing the Web pages, and a two-node server cluster with SQL Server that will be accessed to provide data for the Web pages. Students and instructor will work together to test the fault tolerance and scalability of the classroom configuration.

 Objectives After completing this lab, you will be able to: Implement an n-Tiered site by using both NLB and Cluster service technology. Implement round robin DNS to improve scalability. Demonstrate and explain the fault tolerance capability of the tiers.

Scenario In this lab you will work with other students to build an n-tiered site with your student computer configured as a member of a Network Load Balancing cluster. You will install a sample Web site that is based on ASP pages that will be configured to request data from a 2-node server cluster running SQL Server with a sample database installed. The class will work as two groups to create two NLB clusters. When the NLB clusters are completed the instructor will demonstrate the addition of multiple records to a DNS server allowing the two NLB clusters to be configured as round robin DNS. The instructor will work with the students to test the classroom configuration and demonstrate the fault tolerance of both the NLB clusters and the SQL Server running on Cluster service.

Exercise 1: Configuring the NLB Cluster Ensure that all students have completed the configuration of NLB before allowing them to continue with the installation of the Web site files. If you have implemented any changes in the sample site or the SQL Server configuration, ensure that you advise the students of the names and accounts to use when configuring database access. To artificially limit the capabilities of the NLB cluster, the students can be told to throttle the Web site by using the IIS administrator.

When creating a script by using the Web Application Stress tool, demonstrate to the students the creation of the script by browsing the student Web site. When the script is completed, you must enter the URL or IP address in the Web Application Stress tool user interface to exercise the script against the Web site. For the demonstration of the Web Application Stress tool, select students from each cluster to disconnect their computers from the network. The Web Application Stress tool will pause in the script when addressing the missing student computers, but will then recover and the load will be redistributed among the remaining cluster members.

In this exercise, you will: Work with other students in your group to configure half of the student computers as a Network Load Balancing cluster. Verify that the Network Load Balancing cluster is operating correctly. Install a sample Web site. Configure IIS to use the cluster IP address.

Scenario Using the information that is provided in the worksheet and reference table that describe the implementation details of the Network Load Balancing cluster, re­ configure your student computer to join a Network Load Balancing cluster. Students will split into two groups, even numbered student IDs in one group and odd numbered student IDs in the other.

 To configure your computer to join the new cluster 1. Disable the network adapter that will be used for Network Load Balancing to prevent IP address conflicts with other students during configuration. 2. Use the worksheet information and Reference Table to configure the Network Load Balancing driver and Transmission Control Protocol/Internet Protocol (TCP/IP) properties. 3. Enable the network adapter. 4. Confirm the correct configuration of the computer by using Wlbs.exe. 5. Cooperate with other students in your group to ensure that all of the member servers are correctly configured and the cluster converges. 6. When all of the cluster members are converged, advise your instructor. The instructor will advise you when to complete the next procedure.

 To install the sample Web site and configure IIS to use the cluster IP address 1. Connect to \\London\Public and double-click unzip_ado.exe to install the Web site on your local cluster member computer. Install the Web files in c:\Inetpub\Wwwroot to add the Web site as a sub web in the default Web site. 2. Modify the file c:\Inetpub\Wwwroot\Web\Global.asa to access SQL Server running on Cluster service. Change the string, which defines the server to SQLserver in the definition for Provstr. Note: The instructor may use a different name for SQLserver. If the instructor provides alternative names, use them.

3. Using the IIS Microsoft Management Console (MMC), add a new virtual directory to the default Web site by using C:\Inetpub\Wwwroot\Web named Northwind. 4. Using the IIS MMC, configure IIS to use the cluster IP address. 5. Use Internet Explore to verify that you can access //ClusterIP/Northwind/ Browse the sample Web pages and ensure that access to the SQL Server database is successful; you can verify this information by ensuring that record set data is returned when querying for product data. 6. When you have completed the verification of the Web site, advise your instructor.

 To follow along with the instructor demonstration of the Web Application Stress tool by accessing the second class NLB clusters 1. Start the Web Application Stress tool and create a script by using the manual icon to access each of the Web clusters. 2. Students can start the Task Manager on each member of the cluster that is being tested. 3. Start the test script on one cluster by using the IP address of the cluster, and show the Task Manager view of the SQL Server node that is active. 4. Manually fail over SQL Server to the second node. While this is occurring, discuss the traffic patterns for the stress tool. 5. When the failover of SQL Server is complete, stop the script and show the errors that occurred during failover. 6. Demonstrate the failover process again by using the second class cluster.

7. Demonstrate entering two records in the DNS server for the classroom, both with the same Uniform Resource Locator (URL), and using both the classroom cluster IP addresses. For example, the following records could be used: a. Cluster.nwtraders.msft Host b. Cluster.nwtraders.msft Host Create a script to access the URL that is used for the class cluster. 9. Run the script by using the class URL and discuss the load balancing occurring in the student computers. Note: The Web Application Stress tool will access the DNS server every time a client accesses the Web site; the Web Application Stress tool will allow the traffic to be evenly distributed across all of the student computers. 10. Note the load on your Network Load Balancing computer. Note: Your instructor will select who will disconnect their computers from the cluster to observe the redistribution of the network load.

Review Application of Clustering Technology Testing Tools