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DESY WindowsNT Web-Services. Henner Bartels DESY WindowsNT Group. Abstract. I will present the DESY WindowsNT solution for providing web services to our NT community.
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DESY WindowsNT Web-Services Henner Bartels DESY WindowsNT Group SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Abstract • I will present the DESY WindowsNT solution for providing web services to our NT community. • As an example for web-based computing an intranet application scenario displaying our NT domain management tools will be reviewed. SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Topics of Discussion • Motivations for implementing NT-based web-services • Implementation of our IIS-cluster • Application design considerations • NT domain management scenario SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Motivations for Implementing NT-based Web-services • Demands of the WindowsNT group • Requests of DESY groups • End-user support SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Demands of the WindowsNT Group • Increasing demands for web-based, cross-platform capable computing • NT domain administration • MS BackOffice family relies on services provided by IIS • Exchange, Office, WebDAV • MTS, MSMQ • Simplified global collaboration and data exchange SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Requests of DESY Groups • Complex web sites needed without having to setup a dedicated web server • None or minimal management overhead desired • Server-side scripting (e.g. CGI, ASP) • Access to other domain resources • Secured and closed forums SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Group Webs • Group web spaces appear as sub-directories in the WindowsNT web • Full server-side scripting support including Perl, VBScript and others • Domain resources can be accessed using ActiveX, ADO, ADSI and MTS • No management overhead • No support for https (using NT ACLs) SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
End-User Support • Personal web pages(e.g. www.desy.de/~hbartels) • Available to users with Unix accounts • No solution for non-Unix users or those preferring to create content on NT without the hassle of file-transfer SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Personal WebPages • Now fully supported(e.g. desyntwww.desy.de/~hbartels) • Web content located in the user home directory • No server-side scripting (security!) • No support for https (using NT ACLs) • A platform-independent solution is still pending SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Implementation of Our IIS-cluster • Key requirements • Server configuration • Cluster setup • Data flow • Manageability • Drawbacks SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Key Requirements • Scalable and robust solution • Simple to manage • Highly integrated with MS BackOffice • Security using SSL, NTFS • Content stored where user and group data are located • Server-side scripting using WSH SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Server Configuration • Compatible industry PC equipped with: • Pentium II running at 350 MHz • 256 MB RAM • 2 IDE Disks (mirrored, < 1 GB used) • 2 NICs (1 onboard / 1 PCI card) • NT Enterprise Server, SP 5 • IIS, Index Server, related Hot-Fixes • Active State Perl SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Cluster Considerations To provide service reliability clustering technologies are employed • MS Cluster Server (Wolf Pack) • Fail-Over Server without load-balancing • Requires (expensive) hardware • Windows Load Balancing Service • No Fail-Over • IP-based load-balancing (up to 32 nodes) • In case a node fails only those connections will have to reconnect SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
How WLBS Works • Cluster NIC sharesIP address andMAC on all nodes • Handles Clustertraffic and inboundconnections • The dedicatedNIC manages theestablished connections SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Switch Hub Cluster Setup SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Switch Hub Client Data Flow SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Manageability • Cluster nodes can be managed using MS Management Console • Configuration changes have to be replicated using scripts (ADSI) • Management of Group Webs will be implemented using a web interface • Setting / Removing IP restrictions • Enabling / Disabling HTTPS • Set directory access rights SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Drawbacks • IIS 4.0 is designed to store content on local disks • Some ISAPI filters (e.g. .hqx) will not work properly • FrontPage Server extensions can not be used • When using HTTPS connections no ACL check is performed, however delegation is properly handled SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Application Design Considerations • Supported clients • Client requirements • Maintaining state information • Using XML / XSL SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Supported Clients • Netscape 3 • Windows 3.11 (NICE) • Netscape 4+ • Standard Unix Browser • Internet Explorer 4+ • Standard(?) NT Browser • Internet Explorer 5 is expected to be the next standard viewer on NT SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Client Requirements To provide a visually appealing and dynamic environment clients have to support: • Frames • At least JavaScript 1.1 • Layers (used in some applications) • No Plug-Ins • No Java /ActiveX SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Maintaining State Information • Use of Cookies • Cookies are usually disabled • Abuse URLs search part to communicate session state • Difficult to maintain with static pages • Interference when search part is used to transport queries or form data • Use global JavaScript variables stored in top-level frame-set • JavaScript has to be enabled SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Using XML / XSL • XML data and accompanying DTDs are used to: • Provide data used in multiple pages • Store configuration information • Markup data displayed by scripts • XML data is processed on the server • XSL will be used to transform data for clients with disabled scripting engines SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
NT Domain Management Scenario • DESY requirements • Commercial solutions • Application design • Remote scripting object • Live demonstration SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
DESY Requirements (I) • Computer and user management at DESY is handled by three groups • User Consulting Office (UCO) • Group administrators • WindowsNT domain administrators • Tasks and scope of authorization vary slightly • Changes of user properties • Removing a computer from the domain • Creation of new groups SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
DESY Requirements (II) • Setting of license-, inventory- and other management information Most of these tasks require elevated privileges, however the number of staff with administrative rights must be small SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Commercial Solutions • Commercial solutions (e.g. TEM) are providing: • Fine-grained control over the various NT management options • NT based management clients • They require time to setup and maintain proper configuration • They do not come with a web-based client • They can not be adopted to reflect site-specific or non-NT related tasks SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Application Design • We have implemented a framework that dynamically adopts to the privileges of the connecting user • Different views exist for managing users, web configuration and miscellaneous tools • Dynamic HTML, client and server-side scripting are providing an advanced and consistent user interface • The DESY Scripting Host (DSH) is used to gather data and perform requested actions with the required privileges SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Usage SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Summary • We have implemented an IIS-based web server using current clustering and load-balancing technologies • We were able to show the availability of our solution by hosting multiple Group Webs over a period of several month • Web-based applications have been successfully implemented and demonstrated no undesired behavior even after forcing cluster nodes to shut down SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999
Next Steps • Automation of cluster management • Extending available tools • Better modularization of components • Migration to IIS 5.0 • Support for WebDAV SLAC HEPNT / HEPIX Meeting October 4. - 8. 1999