Tài liệu Module 1: Introduction to Designing a Highly Available Web Infrastructure pdf

Contents Module 1: Introduction to Designing a Highly Available Web Infrastructure Overview Lesson: Identifying the Features of a Highly Available Web Infrastructure Lesson: Calculating System Availability 11 Lesson: Supporting a Highly Available Web Infrastructure 22 Information in this document, including URL and other Internet Web site references, is subject to change without notice Unless otherwise noted, the example companies, organizations, products, domain names, e-mail addresses, logos, people, places, and events depicted herein are fictitious, and no association with any real company, organization, product, domain name, e-mail address, logo, person, place or event is intended or should be inferred Complying with all applicable copyright laws is the responsibility of the user Without limiting the rights under copyright, no part of this document may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), or for any purpose, without the express written permission of Microsoft Corporation Microsoft may have patents, patent applications, trademarks, copyrights, or other intellectual property rights covering subject matter in this document Except as expressly provided in any written license agreement from Microsoft, the furnishing of this document does not give you any license to these patents, trademarks, copyrights, or other intellectual property  2001 Microsoft Corporation All rights reserved Microsoft, MS-DOS, Windows, Windows NT, Active Directory, BackOffice, FrontPage, Outlook, PowerPoint, Visio, Visual Studio, Win32, and Windows Media are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries The names of actual companies and products mentioned herein may be the trademarks of their respective owners Module 1: Introduction to Designing a Highly Available Web Infrastructure Instructor Notes Presentation: 135 minutes Practice: 15 minutes Discussion: 30 minutes This module provides the students with an overview of the features of a highly available Web infrastructure, how to calculate availability, and what processes they can use to support a highly available Web infrastructure As a Web infrastructure designer, the student will be required to position mission-critical applications and services in their highly available Web infrastructure and identify the requirements for each of these applications and services The student must ensure availability if an application or service fails by identifying the possible single points of failure in the infrastructure After completing this module, students will be able to: ! ! Calculate the availability of a Web infrastructure ! Required materials Identify the characteristics of a highly available Web infrastructure Analyze the solution architecture To teach this module, you need the following materials: ! ! Delivery Guide ! Preparation tasks Microsoft® PowerPoint® file 2088A_01.ppt Trainer Materials compact disc To prepare for this module: ! Read all of the materials for this module ! Complete the practice and discussion iii iv Module 1: Introduction to Designing a Highly Available Web Infrastructure How to Teach This Module You will notice a new instructional design and strategy for this module and the rest of the modules in this course The modules were designed by analyzing the job functions of a Web infrastructure designer, which then became the modules titles For each job function, the applicable tasks were then identified Each task is a lesson in the module At the end of each lesson (task), there is a guidelines page for the task that identifies the actions steps that the students must address to complete the task To further assist the student in applying what they have learned, there are best practices where appropriate for each topic on the guidelines page You may find it useful to tell the students that for each lesson the guidelines page is what they will work toward Each of the action steps on the guidelines page will have supporting content on the topic pages if this is required You may find that some of the action steps will not require additional information because it is assumed that the student already has the prerequisite knowledge for that step Ensure that the students understand that each lesson is a critical task in the design process and, at the end of the module; they will complete a lab that helps to tie all of the lessons (tasks) together This understanding will help the student to stay focused during instruction The instructional strategy for this course is to introduce the students to the concepts of a highly available Web infrastructure, how they assess the availability of their Web infrastructure, and the processes that they need to incorporate into their Web design Lesson: Identifying the Features of a Highly Available Web Infrastructure The overview page for this lesson introduces the characteristics of a highly available Web infrastructure It also provides a brief introduction to how the student can make the front-end and back-end systems more highly available Their ultimate goal is to identify and eliminate single points of failure The topic pages for this lesson and the appropriate instructional strategies are listed as follows: A highly available Web infrastructure This page provides a high level introduction to how the student can increase availability and where they should concentrate their efforts The content is self explanatory and does not require that you spend a lot of time on each subtopic The overall goal of the page is to identify the following features of a highly available Web infrastructure and how they can improve availability: ! Increasing availability ! Networking infrastructure ! Security mechanisms ! Management and operations Module 1: Introduction to Designing a Highly Available Web Infrastructure Load-balancing technologies This page provides an overview of load-balancing technologies The students should already be familiar with the concepts (prerequisite knowledge) and you not need to spend more time than it takes to read the slide and add a brief comment To prepare for this page, you should have taken Course 2087A, Implementing Microsoft® Windows® 2000 Clustering, or be familiar with: ! ! Hardware load balancing ! Clustering technologies Software load balancing Round robin DNS This page provides an overview of clustering technologies The students are expected to know this content You should have taken Course 2087A, Implementing Microsoft Windows 2000 Clustering, or be familiar with: ! ! Microsoft Cluster service ! Overview of Microsoft products Component load balancing Network Load Balancing You should be familiar with all of the Microsoft products that are part of a highly available Web infrastructure, including: ! ! Microsoft Windows 2000 Datacenter Server ! Microsoft Internet Information Services 5.0 ! Microsoft Internet Security and Acceleration Server ! Guidelines for identifying the components of a highly available Web infrastructure Microsoft Application Center 2000 Microsoft SQL Server™ 2000 The guidelines page provides the students with the actions steps that they must address before they can identify the features of a highly available Web infrastructure You should review the action steps with the students and ensure that they understand how these steps map to the task Lesson: Calculating System Availability The overview page for this lesson introduces the concept of calculating availability The students will need to understand how to calculate the mean time between failure, mean time to repair, and system availability The topic pages for this lesson and the appropriate instructional strategies are listed as follows A highly available system This page defines a highly available system in terms of a level of nines (availability class) The content on this page is self explanatory and is primarily prerequisite knowledge on: ! ! Single points of failure Service level agreements Availability classes Most of the content on this page is a review for the students Of special interest is a reference table that lists the recommended Microsoft clustering solution used to eliminate single points of failure • Common points of failure v vi Module 1: Introduction to Designing a Highly Available Web Infrastructure Hardware Reliability This page introduces the importance of predicting hardware reliability The slide graphic identifies the three phases of a hardware component’s life cycle You must understand and adequately explain the dynamics of the three phases of a hardware component’s life cycle • Mean time between failure Calculate mean time to repair This page provides formulas for calculating the mean time to repair (MTTR), or the length of time it would take to repair a failed component You need to explain the importance of MTTR so that the students will understand how they can apply this knowledge when they calculate system availability • Calculating MTTR Calculate system availability Students will learn how to calculate overall system availability After students have determined the mean time between failure and the mean time to repair, they can then determine system availability by using the formula provided Some examples are included that require only a brief explanation ! ! Guidelines for calculating system availability Calculating availability Calculate maximum availability The guidelines page provides the students with the action steps that they must address before they can calculate availability Each action step includes a single best practice that the student should consider Review the action steps with the students and ensure that they understand how these steps relate to the task Practice: Calculating Availability Students are required to read two scenarios and then use the formulas from the lesson to calculate availability They should be able to complete this exercise with very little guidance Lesson: Supporting a Highly Available Web Infrastructure The overview page for this lesson introduces students to the components of a highly available Web infrastructure, which include program design, hardware, delivery mechanisms, and sustaining engineering The topic pages for this lesson and the appropriate instructional strategies are listed as follows: Microsoft Operations Framework This page gives the students a high level overview of Microsoft Operations Framework (MOF) It identifies the three main sources of risks that the students must analyze and prioritize in their Web design Review each of the subtopics and highlight the bullet points for each ! People, process, and technology ! Process model ! Team model ! Technology component ! Risk analysis model Module 1: Introduction to Designing a Highly Available Web Infrastructure Application architecture fundamentals vii You can use the slide to provide a brief overview of the content The student should already be very familiar with the concepts presented on this page ! Development strategies ! Windows DNA ! Two-tier model ! Three-tier model ! N-tier model Infrastructure processes This page addresses the common causes for unplanned downtime and some best practices for maintaining high availability You need to encourage the student to develop an infrastructure process for ensuring that their Web infrastructure will always be highly available Change management process This is the only section that has a high level overview of the change management process Review the steps of the change management process that are outlined on the page You might want to ask the students what process they use in their organizations and how it compares to what is suggested here • Change management process Highly available solution documentation This page provides an overview of the types of documentation that are recommended as part of the design process Review the types of documentation, and if time permits, ask the students what types of documentation they are currently using and why Security policies and procedures This page provides an overview of the types of security policies and procedures that the student should consider while designing a highly available Web infrastructure ! ! Technology considerations Admitting personnel Admitting hardware This page provides a high level overview of the technology considerations and some best practices for each ! ! Software ! Facility considerations Hardware Testing This page provides a high level overview of facility considerations You can use the slide to discuss all of the major points Be sure to review the best practices with the students ! Facilities management ! Assessing single points of failure ! Maintaining physical security ! Best practices viii Module 1: Introduction to Designing a Highly Available Web Infrastructure Guidelines for calculating system availability The guidelines page provides the students with the actions steps that they must address before they can create a design that supports a highly available Web infrastructure Review the action steps with the students and ensure that they understand how these steps relate to the task Tell the students that these steps were not placed in any specific order They can reorder them as required to meet their particular design Emphasize to the students the importance of addressing all of these requirements Discussion Allow thirty minutes for the discussion at the end of this lesson Give the students approximately minutes to read the scenario, minutes to answer the five questions, and the remaining 20 minutes to discuss the answers as a class Divide the class into design teams of three or more people Try to learn who the more and less experienced students in the class are so that you can create evenly skilled teams Let the students know that each team will present and justify their answers to the rest of the class Module 1: Introduction to Designing a Highly Available Web Infrastructure Overview ! Identifying the Features of a Highly Available Web Infrastructure ! Calculating System Availability ! Supporting a Highly Available Web Infrastructure *****************************ILLEGAL FOR NON-TRAINER USE****************************** Introduction As the Web infrastructure designer, you will be required to position missioncritical applications and services in your highly available Web infrastructure and identify the requirements for each of these applications and services You must also identify the possible single points of failure in the infrastructure so that you can ensure availability if an application or service fails As you design your Web infrastructure solution, you need to consider the following questions: ! What are the specific requirements for your clustering solution? Determine whether you need to coordinate with other hosts or nodes in a cluster or provide data backup or content replication ! What are your software compatibility issues? Determine whether the clustering technology can support your Web applications or if the applications are stateless, or they maintain a client-side state ! What are your hardware compatibility issues? Determine whether the hardware components that you want to use are on the Hardware Compatibility List (HCL) ! What are the expected changes in size and performance requirements for your applications and services? Using business requirements, anticipate the projected growth for your Web infrastructure solution ! What is the impact of downtime to the organization? Determine the potential impact to the organization if the system cannot maintain a specific level of availability Impacts to the business can include a decline in customer satisfaction, loss of competitiveness, or increase in costs Module 1: Introduction to Designing a Highly Available Web Infrastructure Physical and logical networks While you are designing your network infrastructure, you use hardware data to document your infrastructure’s physical structure; you then use the physical structure to document the positioning of services and the configuration of the protocols that you will use in your network You also need to document the organization of your logical network, name and address resolution methods, and the positioning and configuration of services that you use This course teaches principles that are used to design a highly available Web infrastructure solution by using Microsoft applications, services, and technologies It also provides guidelines that you can use as you design your physical and logical networks The lesson practices and module labs allow you to apply what you have learned In addition, you can use the worksheet at the end of each module as a job aid Note Planning strategies for a cluster backup and recovery and for site disaster recovery are beyond the scope of this course Module objectives After completing this module, you will be able to: ! Identify the features and components of a highly available Web infrastructure ! Calculate the availability and reliability of a highly available Web infrastructure ! Identify the processes that are required to support a highly available Web infrastructure 28 Module 1: Introduction to Designing a Highly Available Web Infrastructure Change Management Process Iss ue Identify Issue Identify Issue Justification Justification Implement Implement Document Document Approval Approval Test Test *****************************ILLEGAL FOR NON-TRAINER USE****************************** Introduction The change management process ensures a stable Web solution environment no matter what changes are made Changes can include installing, deleting, and modifying services or applications, in addition to adding, reconfiguring, or removing hardware A proper change management process ensures that full justification is received for every change to the data center environment Change management process Change management operates at two levels: planned changes and emergencies With planned changes, usually one or more computers are changed, typically at a scheduled interval The following steps illustrate a change management process You can modify this process for both planned and emergency changes Identify the issue Identify the improvement or problem that needs to be addressed Provide justification for the change When changing an application or a service, you must not only justify the immediate change, but also any changes required to related applications or services For example, you have justification for moving messaging services into the data center But in deciding which messaging platform to use, other issues arise Planning for messaging with Exchange 2000 Server as part of your solution requires more than just the Exchange service Exchange 2000 Server also requires access to a domain controller, Simple Mail Transfer Protocol (SMTP) services, and Network News Transfer Protocol (NNTP) services So the justification for adding messaging on the Exchange platform must also include justification for the ancillary services that it requires Obtain approval for the change Obtain technical and budgetary approval of the change Test the change Implement the change on a test system to ensure stability and reliability Module 1: Introduction to Designing a Highly Available Web Infrastructure Document the change Change control has two aspects to it: getting consensus on when to make a change, and making sure everyone knows what changes have been made Implement the change Bring the change online and into production Note Because change and configuration management is outside the scope of this course, it is only covered briefly in this lesson 29 30 Module 1: Introduction to Designing a Highly Available Web Infrastructure High Availability Solution Documentation Technical History Technical History ! ! Process Descriptions Process Descriptions Original purpose ! Original configuration ! ! ! Change Log Change Log What When Why was Test What When Why was Test changed? changed? ititchanged? results changed? changed? changed? results ! Impacts Impacts Day-to-day operations Implementing a new process Changing a current process Management of processes Rollback procedure Who made Who Who made Who change? approved? change? approved? *****************************ILLEGAL FOR NON-TRAINER USE****************************** Introduction In your highly available Web solution, you must document all of the details of your Web design so that the implementation teams understand your decisions You must create documentation that explains the technical history, describes every process, and logs all of the changes that you have made as you fine tune your Web design A change log works best as an electronic document that users can reach from any management computer Often the best change log uses a plain text file to store the changes Module 1: Introduction to Designing a Highly Available Web Infrastructure Documentation types 31 The following table lists the types of documentation that you must create and describes each documentation type Type of documentation Description Technical history Original purpose of the Web infrastructure Original configuration of the Web infrastructure Process descriptions Defined day-to-day operations Implementing a new process Changing a current process Managing processes Change log Current state of everything in the Web infrastructure to provide a comparison with the technical history Change log for every server What was changed? When was it changed? Why was it changed? What are the test results? What impacts might be expected from the change? Who made the change? Who approved the change? Rollback procedures What triggers must occur for the rollback to be warranted? What impacts might be expected from the rollback? What tests will validate that the rollback is successful? 32 Module 1: Introduction to Designing a Highly Available Web Infrastructure Security Policies and Procedures To ensure a secure environment for your Web solution, you will create a process for: ! Admitting personnel " " Describe where they are permitted to go " ! Describe who can be granted access to the facility Describe what they are permitted to Admitting hardware " Anticipate the disruption to service " Determine hardware functionality *****************************ILLEGAL FOR NON-TRAINER USE****************************** Introduction You may be responsible for defining stringent policies and procedures to secure your servers, communications equipment, and n-tier environment You must have a process that governs how your organization implements and changes security In addition, you must define the process for admitting personnel, hardware, and software to the data center that contains your solution, whether that data center is on site or hosted by an ISP Admitting personnel You must implement a security management process that describes who can be granted access to your facility, the pattern of their movement after they are inside, and what they are allowed to To accomplish effective security management, you must understand all of the levels of required access When reviewing the security for your Web solution, review your methods for restricting access to remote administration of servers Make sure that only the individuals that you designate have remote access to your configuration information and administration tools Admitting hardware Before you can admit a piece of hardware into your highly available Web solution, you must have a process that determines what the disruption to service will be As part of this process, you must check hardware for functionality before you introduce it to the highly available solution environment Module 1: Introduction to Designing a Highly Available Web Infrastructure 33 Technology Considerations Hardware Hardware Software Software Testing Testing *****************************ILLEGAL FOR NON-TRAINER USE****************************** Introduction Technology considerations for your highly available Web solution include hardware, software, and testing components Hardware extends beyond the server to the networking infrastructure and other required hardware for special needs Hardware Adopt a standard server type that includes a standard network card, disk controller, graphics card, and other components Use this standard server type for all applications, even if it is more than needed for some applications The only parameters that you can modify are the amount of memory, number of CPUs, and the hard disk configurations Software You need to understand how each application runs and how it relates to the operating system and other applications that run on a server Select software that supports the high availability features that you require Not all software supports features such as redundancy, load balancing, or server clusters Testing Hardware and software components require thorough testing before installation and continuous monitoring after installation Testing concerns for the technical part of the data center include servers and storage, networking, and software qualifications Note Because testing is beyond the scope of this course, it will be covered briefly only in this lesson 34 Module 1: Introduction to Designing a Highly Available Web Infrastructure Facility Considerations Power Supply Power Supply Network Connectivity Network Connectivity Natural Disaster Natural Disaster • Redundant power supply • High quality hardware • Location • Uninterruptible power supplies • Redundant networking • Seismic racks • Multiple ISPs • Fire suppression • Diverse grids • Generators *****************************ILLEGAL FOR NON-TRAINER USE****************************** Introduction A highly available Web infrastructure could potentially consist of hundreds of servers with a complex infrastructure of communication products, including routers and switches You must examine your physical plant to make sure that you have eliminated any single points of failure from your facilities design Areas that must be covered are the physical manageability of the facility, physical availability, and physical security for the Web infrastructure Facilities management When you plan a manageable facility, you must address several factors, including temperature, humidity, dust, and contamination If you are designing a data center, then you must consider the whole environment that supports your solution If you are using third-party hosting, then you must assess the environmental availability guarantees that are provided by the vendor for your solution Assessing single points of failure You must analyze your facility for every possible kind of failure so that you can eliminate any single point of failure As part of a risk analysis, it is recommended that you consider electricity, network connectivity, and natural disasters as possible failure points In addition, plan for power outages and identify the resources that are most critical to the operation of the solution Maintaining physical security To maintain security in your facility, you must partition areas to reflect the security needs of those spaces You can establish partitions through access levels, locks, smart cards, biometric devices, and other security devices Module 1: Introduction to Designing a Highly Available Web Infrastructure Best practices 35 The following table lists several physical plant considerations and best practices for managing your facility Physical considerations Best practices Climate control Ensure that computer cooling fans are functioning properly; failure of these fans could cause the processor or processors, hard drives, or controller cards to overheat and fail When adding servers to a computer room, make sure that you not exceed the cooling capacity of the room Computers are rated for cooling at about 70º Fahrenheit Keep the humidity low enough to prevent condensation, but not so low that it creates problems with static electricity In a dry climate, you may need to use static electricity suppression False floors and ceilings allow for controlled air to be circulated throughout every area of the facility Protection from dust and contamination Use air scrubbers or other filtering systems Power supply Use a redundant uninterruptible power supply Maintain a clean room Avoid contamination by using airlocks on the doors or by requiring that special attire be worn in the room Use double or triple redundant generators rated to supply enough electricity to power the entire facility Network connectivity Set up easily accessible pathways for redundant sets of cables If you use multiple network connections, try to route the cables feeding the cabinets from different points Use redundant Internet connectivity The best situation is two separate, diverse connections Natural disaster Locate your facility away from fault lines, flood plains, and other areas where natural disasters are known to occur Use seismic racks to insulate servers from shaking Use a redundant fire suppression system that does not damage the equipment 36 Module 1: Introduction to Designing a Highly Available Web Infrastructure Overview of Microsoft Products ! Application Center 2000 ! Windows 2000 Datacenter Server ! Internet Information Services 5.0 ! Internet Security and Acceleration Server ! SQL Server 2000 *****************************ILLEGAL FOR NON-TRAINER USE****************************** Introduction Microsoft products, such as Application Center 2000, Windows 2000 Datacenter Server, Microsoft Internet Information Services (IIS) 5.0, Internet Security and Acceleration (ISA) Server, and SQL Server 2000, can increase performance, reliability, and availability for your Web infrastructure Application Center 2000 Application Center 2000 is designed so that any server can be taken offline without affecting the availability of applications; therefore, there is no single point of failure Because of this functionality, applications can have the necessary mission-critical availability by using off-the-shelf hardware Application Center 2000: ! ! Actively monitors performance and health Provides tools that monitor the cluster and its servers ! Windows 2000 Datacenter Server Insures availability Allows your Web site to withstand software and hardware failures at any point in the system without disrupting application service Automates event responses Monitors server and application health and can take action in response to particular events and conditions Windows 2000 Datacenter Server provides new features that dramatically increase system availability for your critical business solutions With Plug and Play compatibility, you reduce planned system restarts by more than 90 percent The system also gives you clustering, advanced fault tolerance, and file system recoverability features Network Load Balancing clusters provide high scalability and availability for TCP/IP-based services and applications by combining up to 32 servers that run Windows 2000 Advanced Server or Windows 2000 Datacenter Server into a single cluster Module 1: Introduction to Designing a Highly Available Web Infrastructure 37 Server clusters provide high availability for resources and applications by clustering multiple servers running Windows 2000 Datacenter Server If one of the nodes in the cluster is unavailable because of failure or maintenance, another node immediately begins providing service (a process known as failover) Internet Information Services IIS 5.0 introduces several new features to help Web administrators and ISPs create scalable Web applications, Web sites, and Web clusters Advancements in IIS 5.0 Web publishing, security, administration, and applications work together to increase performance and reliability while lowering the cost of ownership and improving the Web application environment Internet Security and Acceleration Server ISA Server secures your network, which allows you to implement your business security policy by configuring a broad set of rules that specify which sites, protocols, and content can pass through the computer running ISA Server ISA Server monitors requests and responses between the Internet and internal client computers, and it controls who can access which computers on the corporate network ISA Server also controls which computers on the Internet can be accessed by internal clients You can deploy ISA Server as a dedicated firewall that acts as the secure gateway to the Internet for internal clients By setting the access policies, administrators can prevent unauthorized access and malicious content from entering the network, and they can restrict outbound traffic SQL Server 2000 SQL Server 2000 can maintain the extremely high levels of availability that large Web sites and enterprise systems require SQL Server 2000 has improved support for Microsoft Windows NT® and Microsoft Windows 2000 failover clustering Support for setting up failover clustering is now implemented as a Setup option that is much easier to use than earlier versions of SQL Server SQL Server 2000 also supports up to four nodes in a failover cluster 38 Module 1: Introduction to Designing a Highly Available Web Infrastructure Guidelines for Supporting a Highly Available Web Infrastructure ! Identify the design strategies for the Web solution architecture that will meet your business requirements ! Identify the infrastructure and change management processes required to implement and support your solution ! Identify the appropriate Microsoft products and technologies based on an n-tier architecture ! Document the architectural decisions for the implementation teams ! Document the security policies and procedures required to protect and sustain your solution ! Identify the system hardware standards, software standards, and testing regimes that are required to support your solution ! Identify the facilities required to adequately support your solution *****************************ILLEGAL FOR NON-TRAINER USE****************************** Introduction A highly available Web Infrastructure design must include all aspects of the solution, including the facilities and support processes that are required to maintain the operation within design limits For small solutions, all aspects of the design may be handled by a single designer; however, for a large complex Web infrastructure, the design processes may be executed by a team of designers with skills in appropriate areas, such as facilities design Design guidelines Before you can design a highly available Web solution, you must analyze your business requirements and determine the following design guidelines: ! Identify the design strategies for the Web solution architecture that will meet your business requirements ! Identify the Web infrastructure and change management processes required to implement and support your solution ! Identify the appropriate Microsoft products and technologies based on n-tier architecture ! Document the architectural decisions for the implementation teams ! Document the security policies and procedures required to protect and sustain your Web infrastructure ! Identify the system hardware standards, software standards, and testing regimes that are required to support your Web infrastructure ! Identify the facilities that are required to adequately support your Web infrastructure Module 1: Introduction to Designing a Highly Available Web Infrastructure 39 Discussion ! Government portal scenario ! Technology component ! Security requirements ! Anticipated site usage ! Customer authentication ! Updating and viewing customer data ! Government employee access ! Data center location ! Hardware requirements ! Questions *****************************ILLEGAL FOR NON-TRAINER USE****************************** Introduction The following scenario summarizes a meeting that you had with a new client who wants you to design their Web infrastructure You will use this summary to reevaluate their business requirements and develop your design process Read through the scenario and then answer the questions that follow the scenario Be prepared to discuss your answers with the class Government portal scenario Your new client is a government that is planning to implement an Internet-based portal to create one-stop, personalized access for Web site customers who want to access government services online Your client wants to call their new portal “Government Portal.” Technology component The Government Portal project must integrate with many existing systems that currently provide stand-alone services New services will be added, for example, an online store that allows clients to purchase books and merchandise from government-funded universities The online store application includes shopping cart and credit card purchase functionality The default home page will be an informational page available for anonymous user access, with no log in required Web site users will log on with a unique account and associated password to gain access to their personalized portal home page Security requirements The Government portal will access government information that is stored in legacy data stores These legacy systems have limited built-in security The security of both clients’ personal information and government information is of critical importance Therefore, data stores for both the portal and legacy systems integrated with the portal must be protected from compromise by the portal solution Anticipated site usage The Government portal must be accessible 24 hours a day, seven days a week for customers and Government employees The Web site must also be available during disaster events, including long-term power loss 40 Module 1: Introduction to Designing a Highly Available Web Infrastructure The population of the area served by the government is 10 million The Government anticipates that 30 percent of the population will sign up for a user account on the Web site, and 20 percent will use the Government Portal on a regular basis The Web site will also be accessed by 30,000 Government employees Of these employees, 2,000 will use the system continuously from the government-wide intranet to access information that is required to answer client queries Customer authentication Web site customers will be able to browse anonymous areas of the Web site to view services and products, and they will be identified by a user name and password when they authenticate on the Government portal They will access a personalized home page where they can configure some of the information displayed on the page When authenticated on the Web site they can: ! Make purchases at the Government University online store ! Pay Government tax bills ! Pay for vehicle registration and title ! Access pay-per-view data, such as title searches prior to purchasing a home ! Use enrolled services, such as a library search at the Government University Updating and viewing customer data From their home page, users will be able to update some of their personal information and access services, such as enrolling for unemployment benefits and registering motor vehicles Some of the customer’s personal information will be read-only access, and only authorized Government employees will be permitted to update this information Government employee access Government employees will log on to the portal by using smart cards, which means that to access the Government portal, they must use Government-provided portable computers or office computers that have a smart card reader installed Government employees will be able to gain access to secure data that is required for their job functions, and they will be able to complete numerous human resources forms, such as vacation or benefits documentation Government Emergency services employees will use the Government portal to update traffic and weather condition advisory information from various places around the region During emergency situations that encompass large regions, such as floods or storms, the Government portal will be a primary communication tool for field personnel Data center location The Government has one main data center in the capitol and three smaller data centers in different cities The main data center has an OC3 connection to the Internet that is provided by a telecommunications provider The smaller data centers have dedicated leased T1 lines to the main data center and they access the Internet through the Internet connection in the main data center Hardware requirements A small-scale pilot project was built for the development of the applications and testing of performance and throughput requirements The hardware for the pilot was based on a selected set of computer and communication products, which can be used in quantity to build the final solution Module 1: Introduction to Designing a Highly Available Web Infrastructure Questions 41 Does this organization require a Web site that is highly available? Why? The organization in this scenario will require that you design a highly available Web infrastructure for the following reasons: The Government’s business requirements dictate that the site be available 24 hours a day, seven days a week for their government clients The site must be available for emergency services personnel Government employees need the Web site to perform some of their daily tasks Is n-tier a good solution for this scenario? Based on the requirement to access legacy data stores and a local database, n-tier would be a good solution because COM+ applications in the business logic tier can access disparate stores with flexible authentication What features would you require in your architecture to include disaster recovery? Because the Government has a main data center in the capitol city and three smaller data centers in other cities, you could consider positioning resources in multiple data centers For this solution to be viable, the bandwidth of the communications channels between the sites should be increased In addition, you may want to consider connections to the Internet from multiple data centers What level of availability you think this solution requires? The students’ answers on availability will vary, but they should consider which areas of the site need to meet the highest availability Most of the services on this site are not critical and therefore not require continuous availability The customers would probably accept site unavailability without complaint for these services However, services for emergency personnel could be considered critical services, and therefore these services may require high availability What information must you acquire to make a prediction of achievable availability levels? You would need to document the reliability figures for current resources or acquire MTBF for the resources from the hardware manufacturers and suppliers Availability for resources such as the Internet connection may be available from the telecommunications supplier or they have supporting reliability data THIS PAGE INTENTIONALLY LEFT BLANK ... a highly available Web infrastructure ! Identify the processes that are required to support a highly available Web infrastructure Module 1: Introduction to Designing a Highly Available Web Infrastructure. .. Designing a Highly Available Web Infrastructure Availability A Highly Available System 9 9 Managed Managed Well-Managed Nodes Well-Managed Nodes Masks Some Hardware Failures Well-Managed Packs and... that you can use when designing a highly available Web infrastructure ! Identify the features of a highly available Web infrastructure 4 Module 1: Introduction to Designing a Highly Available