Windows Azure The Cloud Computing Platform

Transcription

1 White Paper Widows Azure The Cloud Computig Platform TCS Perspectives The whitepaper delves ito the evolvig cloud computig model ad provides a overview of Widows Azure as a cloud platform. It also describes the various tools that are supported by the platform ad compares Widows Azure with other cloud platforms such as Amazo ad Google. Fially the paper details TCS's perspective o Widows Azure ad the future roadmap of the platform.

2 About the Authors Bala Prasad Peddigari (Bala) Bala Prasad Peddigari (Bala) workig with Tata Cosultacy Services Limited for 13 years ad curretly heads the HiTech Iovative Solutios Group at HiTech vertical with a focus o Cloud Solutios. Bala has several Microsoft Certificatios to his credit ad he is also Ope Group Certified Architect ad TOGAF Certified. He is a active cotributor towards Ope Group Cloud Computig workig group ad promotes cloud based techologies across. Girish Phadke Girish Phadke is a Microsoft Certified Architect ad heads the Microsoft Techology Excellece Group i Tata Cosultacy Services Limited. He ispires ad iculcates the kowledge of architecture, software factories ad desig patters. His curret focus areas iclude SOA, Security ad SAAS. 2

3 Table of Cotets 1. About The Authors 2 2. Evolutio of Cloud Computig Model 4 3. Widows Azure Platform Overview 8 Widows Azure Compute 9 Widows Azure Storage 10 Widows Azure Fabric 11 Sql Azure 12 Widows Azure Platform Appfabric Services Implemetig Widows Azure Applicatios 18 Azure Tools 16 Key Implemetatio Challeges 19 Real World Implemetatio Scearios 19 Cloud Adoptio Model Widows Azure Perspectives ad Future Roadmap Coclusio Refereces Ackowledgemets 24 Table of Figures Figure 1: Typical Cloud Platform Architecture 5 Figure 2: Cloud Computig Service Delivery Models 6 Figure 3: Relatioship of Iaas, Paas ad Saas 7 Figure 4: Widows Azure Platform Footprit 8 Figure 5: Widows Azure Fabric 11 Figure 6: Sql Azure Sapshot 12 Figure 7: Wcf Data Services - Glace 14 Figure 8: Sql Azure Data Access Architecture 15 Figure 9: Widows Azure Adoptio Model 20 3

4 Evolutio of Cloud Computig Model To obtai better returs o their ivestmets i Iformatio Techology (IT), eterprises typically adopt several techology trasformatio programs. These techology trasformatio programs are heavily iflueced by the evolvig computig paradigm, from the maiframes to cliet server (distributed ad web), SOA ad web 2.0. To realize cost effective, high performace ad scalable IT ivestmets, eterprises have experimeted with various ew computig models such as grid computig, utility computig ad ow Cloud Computig. Cloud computig is a disruptive force that will sigificatly impact the existig busiess models of techology vedors, systems itegrators ad ISVs i the future. As per Garter s estimate, the cloud computig model will commad a compoud aual growth rate of more tha 22% by 2011 of the eterprise applicatio developmet market. Cloud computig is a iteret based services delivery model where services are hosted over the iteret by a service provider. Cloud service providers have ifrastructure, such as, servers, hardware ad software ad offers this as a service to eterprises. The cloud services ca be cosumed by the eterprises through various chaels, like mash-ups, browser based user iterface, mobile applicatios, smart cliet applicatios deployed i o-premises ad other ope chaels as well, such as, Widows Azure Marketplace data market ad applicatio market. Further, cloud services ca iteroperate with other programmig platforms such as Java ad Flash. Eterprises ca sigificatly lower the total cost of owership of applicatios i a cloud computig model as agaist the o-premise deploymet model. The cloud computig model allows a service provider to leverage a commo shared ifrastructure across a umber of eterprises. Typical billig models that are employed i the cloud paradigm are either subscriptio based or usage based or a combiatio of both. The billig models are also tied to strict SLA compliace by the service provider. It is more importat to classify cloud deploymet models, which are typically orgaized as Public Cloud, Hybrid Cloud, Private Cloud, ad Commuity Cloud Public Cloud: Public cloud (exteral cloud) deploymet model describes cloud computig i the traditioal maistream sese, whereby resources are dyamically provisioed o a fie-graied, self-service basis over the Iteret, via web applicatios/web services, from a off-site third-party provider usig a fie-graied utility computig basis Ex: Amazo EC2, Widows Azure. Private Cloud: Private cloud (iteral cloud) deploymet model details how cloud capabilities are built ito the iteral IT ifrastructure to maage ad moitor missio critical applicatios of eterprises. This model is the perfect choice whe eterprises require cloud computig beefits without compromisig o data security. Hybrid Cloud: Hybrid cloud is also called hybrid delivery by major vedors icludig HP, IBM, Oracle ad VMware who offer techology to maage the complex issues cocerig performace, security ad privacy that results from the mixed delivery methods of IT services. A hybrid storage cloud uses a combiatio of public ad private storage clouds. Hybrid storage clouds are ofte useful for archivig ad backup fuctios, allowig local data to be replicated to a public cloud. 4

5 Commuity Cloud: A commuity cloud ivolves the participatio of multiple teats to share the same ifrastructure ad realize beefits of cloud computig. This optio may offer a higher level of privacy, security ad/or policy compliace. I additio it is also ecoomically attractive as the resources (storage, workstatios) utilized ad shared i the commuity have already bee used to the maximum deliverig a attractive retur of ivestmet. Ex: Google's "Gov Cloud". This cloud deploymet models will ifluece the overall cloud platform architecture i various dimesios. Cloud Platform Architecture A cloud platform typically cosists of a core virtualized ifrastructure that provides computig ad storage services. It also hosts commo services such as provisioig, security, meterig, billig ad moitorig services. Services for user iterface, workflow ad multi-teet database are exposed to the applicatio layer. The cloud platform should also provide a applicatio developmet platform that allows developers to create, test ad deploy applicatios. Typical cloud platform architecture is depicted i the diagram below: Cloud Applicatios ad Services Multi-teat Database, Web ad Workflow Services Ifrastructure Maagemet Services Moitorig ad SLA Maagemet Services Meterig ad Billig Provisioig ad Security Services Cloud Fabric (Rutime) Storage as Service Computig as a Service Applicatio Developmet Eviromet Data Ceter for Hostig Figure 1: Typical Cloud Platform Architecture 5

6 Key attributes that should be supported by a good cloud platform iclude: Idetity Federatio Multi-teat Data Architecture Dyamic UI Bradig based o Request Cotext (relevat to SaaS) Customizatio of Busiess Rules ad Workflow based o Metadata Shared Billig Service Service Maagemet ad moitorig Cloud Computig Service Delivery Models Cloud computig service delivery models ca be further divided ito the followig categories: Software as a Service: Software as a Service (SaaS) vedors help i buildig custom applicatios to provide solutios tailored to specific eeds by developig services that are hosted i the cloud ad ca be cosumed by the ed users. SaaS vedors iclude Salesforce.com, Zoho, Exchage Server, Microsoft Dyamics CRM Olie etc. Platform as a Service: Platform as a Service (PaaS) vedors provide ed-to-ed cloud computig platform with capabilities for applicatio desig, developmet, testig, deploymet ad hostig. Key vedors i the PaaS category iclude Microsoft (Widows Azure), Google (App Egie) ad Salesforce s (Force.com platform). Ifrastructure as a Service: Ifrastructure as a Service (IaaS) vedors provide virtualized computig ad storage resources i the cloud as a service. Key vedors i IaaS category iclude Amazo (Elastic Cloud Computig Platform), 3tera (AppLogic Platform), VMWare (vsphere Cloud OS) ad Citrix (Cloud Ceter C3). The followig figure demostrates each of the service delivery models ad the key players offerig these cloud services: Software as a Service Platform as a Service Ifrastructure as a Service Figure 2: Cloud Computig Service Delivery Models 6

7 The figure below illustrates the relatioship betwee IaaS, Paas ad Saas ad the associated risks ad disadvatages. Ex: Data Security, Network Delays, amog others. Cosumer App App App App App App Servers Servers Servers Service Provider What about etwork delays? Is data Secure? App Web, App & DB Servers Web, App & DB Servers Compute & Storage Compute & Storage Compute & Storage Ifrastructure as a Service Platform as a Service Software as a Service Figure 3: Relatioship of IaaS, Paas ad SaaS The key beefits that eterprises ca leverage as a result of migratig some of their applicatios to the cloud: Ability to leverage the Opex model as opposed to the Capex model for IT ivestmets. Optimized ivestmets i core IT Ifrastructure by movig to the private cloud model. Ability to achieve higher scalability, availability ad performace without upfrot ifrastructure ivestmets. Flexibility to pay as per service usage or subscriptio based ad SLA drive paymet models. Ability to focus o core busiess istead of maagig large IT ifrastructures. The subsequet sectios will focus o Microsoft Widows Azure platform ad its compoets, our experieces ad perspectives o Widows Azure ad its future roadmap. 7

8 Widows Azure Platform Overview With the advet of the cloud computig platform, we are experiecig a paradigm shift i the developmet spectrum, where cloud capabilities are also cosidered whe desigig ad buildig ew applicatios. The key levers ifluecig this shift i hostig applicatios from o-premise to cloud are flexibility, scalability, reduced capital expeses, 24 x 7 availability, geographical access ad lower total cost of owership. However, it is evidet that ot all applicatios are ready to be placed i the cloud. Istead seasoal, omissio critical applicatios that are ot drive by strict compliace or regulatory eeds are the most immediate set of applicatios that ca be moved to the cloud. Microsoft s Widows Azure Platform provides a familiar ad flexible eviromet to drive ad support specific eeds ad services of the developmet team, customers ad users. The Widows Azure platform provides a uiform experiece as it eables developers ad users to use existig Microsoft techologies to develop or use applicatios o-premise or i the cloud. Widows Azure platform comprises the followig: Widows Azure Microsoft SQL Azure Widows Azure Platform AppFabric Existig Software Applicatios SOAP REST XML Your Cloud Applicatio Widows Azure Platform www Ed Users Developers PHP & 3rd Party Laguages AppFabric platform Figure 4: Widows Azure Platform Footprit I a utshell, Widows Azure ca be defied as a cloud operatig system with the ability to host services ad maage them cetrally. This provides a wide rage of capabilities i the form of computig service to ru applicatios, storage services ad creatig a framework that supports several applicatios. Widows Azure Platform lays the foudatio for ruig applicatios ad storig data o the cloud. Widows Azure Platform cotais computer service, storage service ad fabric. Computer service eables applicatios to ru i the cloud; storage service provides storage for cotet types ad the fabric provides a framework to maage ad moitor the applicatios ruig i cloud. 8

9 SQL Azure is a fully relatioal database support o Widows Azure. Widows Server AppFabric ad Widows Azure Platform AppFabric eable the buildig ad maagemet of o-premise applicatios i the cloud. Widows Server AppFabric icorporates capabilities i the form of cachig, workflow ad service hostig while Widows Azure Platform AppFabric Services costitutes services bus for coectivity across the etwork ad access cotrol services for federated authorizatio. Widows Azure Compute Widows Azure platform offers rutime executio eviromet for maaged code to host ad ru scalable solutios. Each Widows Azure Compute istace is also a Virtual Machie (VM) istace created by the platform ad oly the umber of istaces is cofigured by the team hostig the applicatio. Every VM istace rus a Azure aget to coect ad iteract with the Widows Azure fabric. Every VM has a local file system which ca be utilized by the web/worker role istace durig their life-time, but oce the VM istace is shut dow, VM ad local storage will go away. Azure maitais 3 differet istaces of every applicatio o the cloud ad the ed-user will ot be aware of which istace is servig the specific request. Hece persistet storage is required to support the applicatio data ad this ca be met usig the Widows Azure Storage Service. With geographically distributed ceters, Widows Azure Compute provides developers with the fuctioality to build, host ad maage applicatios o the cloud. Applicatio developers ca coect to Widows Azure portal usig Widows Live ID ad choose a hostig accout to host applicatios o the cloud ad a storage accout to store data or ay relevat cotet o the cloud. Certai applicatios ca use either the hostig or storage accouts or both. The accouts eable developers to host ad deploy applicatios o the Widows Azure platform. Widows Azure presetly supports three roles; web role istace, worker role ad VM role. 1. Web Role is customized for web applicatio programmig ad supported by IIS Worker Role is used for performig the backgroud process for the web role. Message queue edpoits are, i geeral, cofigured i the worker role to geerate programs i a asychroous mode. 3. VM Role rus a image (a VHD) of a Widows Server 2008 R2 virtual machie. This VHD is created usig o-premises Widows Server machie, the uploaded to Widows Azure. Customers ca cofigure ad maitai the OS ad use Widows Services, scheduled tasks etc. i the VM role. Oce it s stored i the cloud, the VHD ca be loaded o-demad ito a VM role ad executed. The VHD ca be used as the base image for all istaces of a VM Role. Widows Azure compute istaces have four uique sizes to eable complex applicatios ad workloads as described i the followig table. This eables eterprises/users to choose the appropriate Virtual Machie size to ru their applicatios based o the applicatio complexity ad resource requiremets. 9

10 Compute Istace Size CPU Memory Istace Storage Extra Small Small Medium Large Extra Large 1.0 GHz 1.6 GHz 2x1.6 GHz 4x1.6 GHz GHz 768 MB 1.75 GB 3.5 GB 7 GB 14 GB 20 GB 225 GB 490 GB 1,000 GB 2,040 GB I/O Performace Low Moderate High High High Widows Azure Compute Istaces ca support ative code executio ad applicatios ruig o the.net framework, PHP, Java, Apache TOMCAT, MySQL. However, future expasio of Widows Azure will eable support of multiple laguages ad frameworks, such as, Ruby o Rails, Pytho ad so o. Further, applicatios deployed ca use Web ad Worker Role istaces together for the user load. Multiple Web ad Worker role istaces ca be cofigured usig the service cofiguratio file. Oe poit to remember is that Widows Azure further provides a capability to retai the VMs where ay crash leads to debuggig ad reusig the storage state to ivestigate the causes of the crash. Widows Azure Storage Widows Azure provides three types of storage i the cloud as defied i figure 5 above: Azure Blob provides storage for large biary objects such as video ad images. Azure Table provides structured storage for maitaiig service state. Azure Queue helps i sedig asychroous work request dispatch to eable commuicatio. Azure XDrive helps i storig the data i a durable drive i the cloud. Blob: Blob is a set of blocks which ca store text or biary data. A block blob is optimized for streamig workloads up to 200GB i size ad page blobs are used for radom read/write access of 1TB. Table: Tables are aother storage represetatio o cloud where data is stored i the form of etities ad properties. Tables eable data storage across machies ad eables scale-out storage. Tables ca be cosumed usig REST APIs. This provides the ability to store huge volume of etities i tables that scale ito terabytes. Queues: Queue helps i storig messages that may be accessed by a cliet. A queue s prime fuctio is to eable commuicatio betwee Web ad Worker Role istaces. Web Role istaces ca place user requests which eed to be processed i the backgroud while the Worker Role moitors the queue to process the request ad respod back via the same queue or ay other queue to the Web Role istace. Widows Azure XDrive: XDrive allows Widows Azure to compute applicatios ruig i the cloud ad use the NTFS APIs to store data i a durable drive. This drive allows Widows Azure applicatios to mout a 10

11 page blob, which is a sigle volume NTFS VHD. All areas i the applicatio ca be itegrated with the blob, ad reads come out of the local VM cache or the page blob if there is a cache miss. This allows applicatios to upload/dowload VHDs via blobs, ad the VHD remais durable ad able to survive the failure of the VM, sice it is backed by a paged blob. The etire storage areas ca be accessed usig REST APIs or HTTP stadard calls as blobs, tables ad queues are represeted usig URIs. Irrespective of the storage types data i blobs, tables ad queue get replicated a miimum of 3 times withi the Widows Azure storage across the virtual machies to esure there is NO data loss. This also equips the self-heal capacity to recover the data ad hadle fault-tolerat situatios ad icrease availability uder extreme coditios as well. This data replicatio is possible via the associatio of VM agets with the Widows Azure fabric, which maages ad moitors the applicatios o Widows Azure platform. Widows Azure Fabric Oe of the key features of the Widows Azure is to provide highly scalable solutios to support large volumes of simultaeous users accessig may differet applicatios hosted o the platform. This capability is hadled by providig a scale-out feature withi the platform to maage a sudde icrease i the volume of users accessig the system. The fabric cotroller maages ad cotrols the Widows Azure Fabric ad is resposible for automatig the load balacig to esure the required scalability is achieved. Widows Azure Fabric has parallel virtual machies ruig the image of the applicatios utilizig a Hyper-V, which is a fietued versio specific to Widows Azure. The followig figure displays the Widows Azure Fabric. Fabric Cotroller Automates load balacig ad computes resource scalit Fabric = Fabric Aget Compute Load Balacer Blobs Storage Tables Queues Web Role Istace Worker Role Istace Virtual Machie Virtual Machie Figure 5: Widows Azure Fabric 11

12 Fabric cotroller utilizes the visibility of the cofiguratio file idicatig deploymet requiremets, such as, storage issues, umber of Web ad Worker Role istaces ad so o. The fabric cotroller is otified if a machie fails ad cofigures a ew virtual machie with the same cofiguratio ad adds it to the Widows Azure Fabric to serve the eeds immediately. This esures service availability without seriously impactig the ed-user. Multiple deploymet topology cofiguratios ca be customized usig the iter-role commuicatio feature of Widows Azure which has the capability to commuicate betwee idividual role istaces i the user applicatio. This supports complex topology cofiguratio withi Widows Azure as it is better supports message ifrastructure ad mappig. So far we have covered the core services of Widows Azure platform dealig maily with structured ad relatioal data. Widows Azure provides the same through SQL Azure which will be highlighted subsequetly. SQL Azure Oe of the key attributes of ay applicatio withi the eterprise, over web, is data. As time passes, data grows immesely attributed to differet sources, differet devices ad differet systems. To address the growig size ad scale of the data we eed a solutio which ca address the primary data challeges associated to maageability, scalability ad availability. SQL Azure is the cloud-based techology solutio to deal with relatioal ad other types of data as part of Widows Azure platform. It cotais two primary parts i. SQL Azure Database ad ii. SQL Azure Data Syc. Reportig Busiess Itelligece Referece Data Data Syc SQL Azure Database Symmetric Programmig Model Data Hub Aggregatio Figure 6: SQL Azure Sapshot SQL Azure database addresses few key areas of cocer i terms of database admiistratio fuctios, such as, disaster recovery, replicatio, backup ad others. The data i the SQL Azure database ca be accessed by the Tabular Data Stream (TDS) protocol. 12

13 The top features of SQL Azure iclude: 1. Relatioal Database Maagemet Services a. Create, access, maipulate tables, idexes, views, roles, stored procedures, triggers ad fuctios. b. Executio of complex queries ad jois across multiple tables c. Costraits d. Trasactios e. Temp tables f. Basic aggregatio fuctios Ex: Strig aggregatios, math, date/ time g. Support for trackig billable metrics i real-time ad for historical aalysis 2. Programmability a. Maaged ADO.Net data access b. Native ODBC c. Support for PHP 3. Tools a. SQL Azure Accout portal to provisio logical servers ad databases b. SQL Server Maagemet studio a itegrated eviromet to cofigure ad access the databases o cloud c. Visual Studio 2010 Supports buildig applicatios with data coectios to SQL Azure to desig queries ad perform data bidig operatios i their applicatios. SQL Azure Data Syc SQL Azure Data Syc is aother importat feature of SQL Azure which aims to provide bidirectioal data sychroizatio fuctioality based o the Microsoft Syc Framework eablig symmetry betwee SQL Azure ad o-premise SQL Server. SQL Azure Data Syc allows likig o-premise database to SQL Azure Database, seamlessly movig or sychroizig the applicatios from o-premise to cloud ad ability to provide the offlie capabilities o the database where SQL Azure data syc ca sychroize the data from o-premise ad remote sources. The goal of SQL Azure is to provide aytime ad aywhere access of data by meas of SOAP ad REST iterfaces so data ca be accessed i multiple ways. You ca use the SQL Azure by creatig a storage accout i the Widows Azure platform accout. Each Widows Azure platform accout ca host multiple SQL Azure storage servers ad each storage server ca iclude multiple databases. By default each database server uses the Master database. 13

14 SQL Azure has the followig features: 1. No code syc cofiguratio: Ca be easily cofigured 2. Schedule Syc : Ability to cofigure the iterval for sychroizatio 3. Coflict Hadlig: Ability to hadle the same data chaged i multiple locatios 4. Loggig ad Moitorig: Admiistratio capabilities to moitor ad track the potetial issues associated with the data 5. Data sub-settig: Provides cotrollable levers to sychroize data at table level. 6. Elastic-Scale: Service scales as resource requiremets grow. 7. SQL Azure has programmig ability usig the WCF Data services, ODBC ad PHP data coectivity chaels. 8. SQL Azure supports overall developmet, deploymet ad provisioig of databases o the cloud. 9. SQL Azure provides similar autheticatio ad authorizatio framework as that of SQL Server databases i o-premise systems ad usig firewall security, which ca be cofigured through Azure Maagemet Portal. 10. WCF Data Services ca be exposed as a REST iterface for coectig with SQL Azure database i the back ed Aother importat goal is to improve reuse of the data ad share the data across disparate systems. Keepig the purpose i mid, The Ope Data Protocol, referred to as OData[7], is a ew data-sharig stadard that has bee itroduced to break dow silos ad foster a iteroperate ecosystem for data cosumers (cliets) ad producers (services) that is far more powerful tha curretly possible. It eables applicatios to access a broader set of data, ad helps every data service ad cliet add value to the whole ecosystem. WCF Data Services was the first Microsoft techology to support the Ope Data Protocol i Visual Studio 2008 SP1. It provides developers with cliet libraries for.net, Silverlight, AJAX, PHP ad Java. Microsoft ow also supports OData i SQL Server 2008 R2, Widows Azure Storage, Excel 2010 (through PowerPivot), ad SharePoit Data Service Cliets Power Pivot HTTP (Ope Data Protocol) Widows Azure Table Storage SQL Server Reportig Services Data Services Data Services Framework Sharepoit Services Sharepoit Figure 7: WCF Data Services - Glace 14

15 Figure 8 provides the data access architecture of SQL Azure database from applicatios both withi ad outside the cloud. To reduce the latecy, we ca esure that the applicatios ad SQL Azure database are hosted i the same cloud platform. As a result, the time lag ca be sigificatly reduced betwee applicatio ad data i the database. Applicatio REST Cliet Browser Applicatio Applicatio SQL Cliet* ODBC, OLEDB, WCF Data Services, PHP, Ruby,... Cloud HTTP+REST HTTP TDS Data Ceter Widows Azure REST Web App ADO.Net+EF SQL Cliet* TDS+TSQL Model SQL Azure * Cliet access eabled usig TDS for ODBC, WCF Data Services, OLEDB, PHP-SQL, Ruby... Figure 8: SQL Azure Data Access Architecture To query this data from the applicatios hosted outside the cloud ca be doe through TDS, HTTP or HTTP+REST protocols. Applicatios hosted i the Widows Azure platform use TDS protocol ad the TSQL model to access the data from SQL Azure. The key beefits with SQL Azure are: 1. Supports multi-teat. 2. Ease of use simple provisioig ad deploymet of multiple databases 3. Built-i high availability ad multi-tolerace 4. No physical admiistratio is required 5. Ability to scale up or dow based o busiess eeds. 6. Support T-SQL based relatioal data model 7. Itegratio with SQL Server ad Visual Studio tools for desigig ad buildig 15

16 Widows Azure Platform AppFabric Services To build applicatios o Widows Azure, the Widows Azure platform AppFabric services ca be leveraged icludig the Service Bus ad Access Cotrol Services this helps i coectig applicatios residig opremises to the cloud. The AppFabric icludes the followig: Service Bus - Service Bus is used to eable applicatios ad services to commuicate across the etwork ad orgaizatioal boudaries for both o-premise ad cloud applicatios. Access Cotrol - Access Cotrol helps to create highly secure authorizatio for applicatios, services ad users usig a orgaizatio s existig ifrastructure. Access Cotrol Services [8] provides a claims-based idetity model to support sigle-sig-o, federated idetity ad role-based access. This service orchestrates the autheticatio ad authorizatio of users usig Widows Live ID, active directory or ay other user idetity store to support stadard idetity federatio protocols. Access cotrol services comprise three etities: a Security Toke Service (STS), admiistratio portal ad admiistratio API. STS issues security tokes, admiistratio portal helps use tokes ad defies claim types, rules ad authorized STS providers. Admiistratio API is used to program ad costruct cofiguratio settigs. Claim based idetity maagemet is the future for maagig idetities ad this is eabled by the access cotrol service of AppFabric. So desigig applicatios to accept idetity ad perform authorizatio based o claims will eable the itegratio of applicatios deployed i the private cloud with those i the public cloud. Service Bus represets a eterprise service bus patter desiged to operate o highly scalable data ceters workig withi the scope of the iteret. Microsoft service bus provides federated idetity ad access cotrol mechaisms, a dyamic service registry ad a robust messagig fabric capable of overcomig the coectivity challeges. A importat compoet of service bus messagig fabric is a cetralized relay service supportig may trasport protocols ad web service stadards (such as. REST, SOAP). The relay service provides differet relay coectivity optios ad helps i egotiatig peer to peer coectios. Service bus fuctioality is built o top of the Widows Commuicatio Foudatio. The Service Bus provides a secure, stadards-based messagig fabric for coectig applicatios across the Iteret, makig it possible to pass through difficult firewall ad NAT obstacles whe ecessary. It offers a ew set of WCF bidigs without sigificatly alterig the rest of the WCF programmig model. A few such bidigs iclude Net Tcp Relay Bidig, Net Oe Way Relay Bidig, Net Evet Relay Bidig ad so o. I short, the service bus eables Widows Azure applicatios with existig applicatios ad databases; it acts like a bridge for o ad off-premise applicatios ad also costructs composite applicatios. 16

17 Implemetig Widows Azure Applicatios Buildig applicatios usig the Widows Azure platform is ot very complicated as developers ca write familiar.net code usig Visual studio to build applicatios, which have the capability to ru i the cloud. Developers ca completely leverage their existig kowledge of.net, Workflow Foudatio, Widows Commuicatio foudatio, SharePoit, Widows Live ad SQL Server to build cloud applicatios. The oly differece will be the way applicatios eed to be deployed ad hosted (i the cloud) ad the executio eviromet of the applicatios (o the developmet fabric or i the cloud fabric). For buildig large-scale cloud-based applicatios o Azure platform, may tools ad service offerigs ca be used ad leveraged. For istace, Widows Azure AppFabric services ca be used for security ad coectivity, SQL Azure for data storage ad retrieval from cloud relatioal data store ad other mash-up services ca be exploited for eablig data sychroizatio from services, applicatios ad devices. The implemetatio methodology follows the simple practice of modelig the services ad decides if either a completely ew applicatio eeds to be developed or if the applicatio ca be composed through other mash-up services or chaels. This is to build a ew service to support market eeds or cosume the services which are already available i the marketplace. For a quicker method, the cosumptio of services ca be leveraged through the Widows Azure Marketplace. Widows Azure Marketplace Widows Azure Marketplace [9] is a olie marketplace for evagelists to cotribute, search, purchase ad exchage buildig block compoets, traiig, service templates, premium data sets plus fiished services ad applicatios eeded to build Widows Azure platform applicatios. The marketplace cotais data ad applicatio market sectios that iclude data, imagery, ad real-time web services from leadig commercial data providers ad authoritative public data sources. Customers will have access to datasets such as demographic, evirometal, fiacial, retail, weather ad sports. Data market also icludes visualizatios ad aalytics to eable isights ito data. The applicatio market sectio of the Widows Azure Marketplace icludes listigs of buildig block compoets, traiig, services, ad fiished services/applicatios. These buildig blocks are desiged to be icorporated by other developers ito their Widows Azure platform applicatios. Other examples iclude developer tools, admiistrative tools, compoets ad plugis, ad service templates. 17

18 Azure Tools The followig table highlights the Widows Azure tools that help develop, test ad deploy Azure applicatios. Phase Tools Descriptio Developmet Tools Visual Studio IDE Itegrated developmet eviromet to eable the creatio, buildig, debuggig, ruig ad packagig of scalable web applicatios ad services for Widows Azure. Developmet Fabric Developmet Storage Simulates the Widows Azure fabric o your local machie so that you may ru ad test your service locally before deployig it. Utility that simulates the Blob, Queue, ad Table Storage services available i the cloud. Developmet Project Elemets Cloud Service The project specifies the Web Role ad Worker Role projects ad cotais the cofiguratio iformatio for the service. It also provides ru/debug ad the publish fuctioality. Web Role Worker Role Service Package Web Role produces a web site for Widows Azure, ad is the etry poit for users to your applicatio. Each cloud service ca have zero or oe Web Role. Worker Role is a backgroud processig compoet. It does ot accept iboud etwork coectios. Each cloud service ca have zero or oe Worker Role. Service Package cotais your Web Role ad/or Worker Role. You ca upload this package alog with the Service Cofiguratio file to Widows Azure via the Widows Azure Developer Portal. Maagemet Cosole Widows Azure The Widows Azure Maagemet Cosole eables you Maagemet Cosole to costruct the claims associated to AppFabric (Widows Azure access cotrol service usig a user iterface. AppFabric Services) Widows Azure Maagemet Cosole (SQL Services) To maage storage accouts i Widows Azure ad makes it simpler to create, debug ad explore the s torage solutios. Eviromets Developmet Available i the developer s local machie to build ad test Eviromet the solutios. Stagig Eviromet Productio Eviromet Widows Azure developer platform provides a GUI to move the applicatio ito the cloud from the developmet eviromet either by usig the hostig accout or storage accout or both. The URL used to access the applicatio will be based o GUID. After completig the applicatio testig o cloud, the applicatio ca be moved to the productio eviromet usig the same GUI i Widows Azure developer platform. Here the URL is user-friedly ad ca be mapped to ay uique domai specific ame. Table 1: Widows Azure Tools 18

19 Key Implemetatio Challeges The key challeges ecoutered i Widows Azure implemetatio are as follows: Idetity challeges. Storage challeges. Commuicatio challeges. The key aspect associated with the idetity challege is to address the issue of idetity federatio whe opremise idetity providers ad applicatios eed to iteract with idetity providers ad applicatios i the cloud. Widows Azure AppFabric access cotrol service ad Geeva framework eables to build claimsbased idetity maagemet solutios for the applicatios this ca help build applicatios that support idetity federatio. The storage challege is to provide scalable data storage for similar applicatios used by multiple customers/teats; aother challege is to offer data security measures, to esure security. This challege is addressed by the SQL Azure relatioal database storage usig the multiple storage tokes whereby each toke ca be used by each teat to store ad access their data securely. Commuicatio challeges revolve aroud employig a efficiet mechaism to trasmit ad commuicate while eablig bulk processig ad computig activities. The Azure queue aids asychroous commuicatio betwee the Web ad Worker Roles ecessary to perform certai tasks, with a careful adoptio of appropriate relay bidigs to achieve optimum performace levels. Real world Implemetatio Scearios Here are few real world scearios that ca be implemeted usig Widows Azure: Sceario 1: A existig.net based payroll system of ABC Corporatio is already deployed i a o-premise private cloud eviromet that eeded to be moved to the public cloud platform. As a result, the applicatio would have to be re-factored for the cloud eviromet. The desig would be based o access cotrol services ad claims-based idetities. The pay slip geeratio, which happes oce i a moth, ca be hadled by Worker Role based o a trigger cotrolled by the Web Role istace of the applicatio. These pay-slip formats ca be stored i blobs while the metadata associated with it ca be stored i the Azure Tables. Sceario 2: A Educatio Board i a coutry coducts differet exams for the studets. The exams are coducted oce i a year ad the results are aouced after evaluatio. The board required that results are made visible to studets the very day it is aouced. This is a highly seasoal applicatio that could leverage the scale-up ad scale-dow capabilities to avoid the huge capital expediture that would be ivolved cosiderig the limited time frame. 19

20 Sceario 3: A retail store chai wats to maage its workforce optimally by schedulig work across all the stores based o regio, locatio ad work fuctios. This solutio ca be developed usig the cloud platform. The etire schedulig activity ca be maaged by the backgroud Worker Role by applyig the relevat store ad work fuctio rules. The workforce is thus able to access their schedule ad maagemet ca alter the rules based o the store demad. Cloud Adoptio Model A eterprise plaig to take the first step towards cloud computig usig Widows Azure platform should, i our view, follow a sequetial adoptio model over time to realize the maximum beefits. The figure below highlights the cloud computig adoptio model i a eterprise: Self-Service Provisioig Applicatios Self Service provisioig applicatios o Cloud Platform Full Services adoptio of Cloud Platform Missio-critical Applicatios Movig missio-critical applicatios to Cloud Exploitig Cloud for eterprise busiess eeds Ivestmet No-missio Critical Applicatios Movig o-missio critical applicatios to Cloud Layig Cloud foudatio at eterprise Seasoal Applicatios Movig Seasoal Applicatios to Cloud Platform Assess ad experimetatio with Cloud eviromet Utility, trial ad experimetal applicatios Applicatios which requires utility computig, trial applicatios ad experimetal/research apps First Step towards Cloud adoptio Time Figure 9: Widows Azure Adoptio Model 20