Cloud Computing. Up until now

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1 Cloud Computing Lectures 17 Cloud Programming Up until now Introduction, Definition of Cloud Computing Pre-Cloud Large Scale Computing: Grid Computing Content Distribution Networks Cycle-Sharing Distributed Scheduling Cloud: Map Reduce Storage Execution Monitoring 1

2 Outline Cloud Programming Models Azure Applications Cloud Programming The cloud has many faces: SaaS, PaaS, IaaS IaaScan be seen as the exposure of low-level services: storage, execution, monitoring. PaaS programming models have three components: Web applications: Google App Engine, Microsoft Azure Parallel processing: MapReduce, DryadLINQ, MPI, Query languages: Simple DB, Pig Latin, etc 2

3 Azure Programming Azure Applications A Microsoft Azure applications is made of Web Roles e Worker Roles: Web Role: Web Service on a VM Windows running in IIS. It s an.aspxpage deployed on a userchosen URL, e.g. myapp.cloudapp.net, and associated to a virtual IP address (VIP). Worker Role: Services without outside interface running on a Windows VM. C# class derived from RoleEntryPoint. 3

4 Service Model: Web Role + Worker Role VIP Windows Azure Storage (Blob, Table, Queue) Web Role: aspx <%@ page language="c#" CodeFile=" ="CodeBehind_cs.aspx.cs CodeBehind_cs.aspx.cs" Inherits="CodeBehind_cs_aspx CodeBehind_cs_aspx" %> <html> <head><title>asp.net CodeBehind Pages</title></head> <body> <form runat="server"> <h1>welcome to ASP.NET 2.0!</h1> <b>enter Your Name:</b> <asp:textbox ID="TextBox1" Runat="server"/> <asp:button ID="Button1" Text="Click Me" OnClick="Button1_Click" Runat="server"/> <asp:label ID="Label1" Text="Hello Runat="server"/> ="server"/></form> </body> </html> 4

5 Web Role: Code Behind using System; public partial class CodeBehind_cs_aspx : System.Web.UI.Page { protected void Button1_Click(object sender, EventArgs e) { Label1.Text = "Hello " + TextBox1.Text; } } Worker Role Instance Communication with the web rolesis done using storage or Queues. Programming: OnStartmethod: used for application initialization. Called before the application is running. It s run by the load balancer. Método OnStop: called when an application is stopped. Método Run: contains the worker role s service. All worker roleshave to start a thread that does not finish in order for the worker rolenot to be terminated. If the Runmethod returns, the application instance is recycled. The Runmethod of the RolePointEntrybase class starts a thread that does an infinite loop. Deployment: once the worker node is created in the Azure administration portal, it s installed via Visual Studio or command line tool. 5

6 Worker Role: Exemplo public class MyWorkerRole : RoleEntryPoint { public override bool OnStart() { DiagnosticMonitor.Start("DiagnosticsConnectionString"); return base.onstart(); } public override void Run() { var daytimeserver = new DayTimeTcpServer(RoleEnvironment.CurrentRoleInstance.InstanceEndpoi nts["daytime"].ipendpoint); daytimeserver.start(); int count = 0; for ( ; ; ) { } } } } count ++; Trace.WriteLine(String.Format("Message {0}", count)); Thread.Sleep(TimeSpan.FromSeconds(10)); Service Model The service model describes the app s characteristics: Which roles and how many. Communication endpoints and their protocols. Which interfaces are exposed. Number of fault domain: Inthesamedata center, onhowmanyrackswilltheapprun. Number of update domain: Iftheappisupdated, howmanyinstancesare updatedatonce. DescribedinanXML file.csdefand.cscfgderived mostly from Visual Studio configurations. 6

Service Model: example <?xml version="1.0"?

name="fulltrust_webrole"> <Instances count="1" />

name="fulltrust_workerrole"> <Instances count="1" />

Web+WorkerIntegration using Queues Typical situation: Web Role:

7 Service Model: example <?xml version="1.0"?> <ServiceConfiguration servicename="fulltrust" xmlns=" 10/ServiceConfiguration"> <Role name="fulltrust_webrole"> <Instances count="1" /> <ConfigurationSettings> </ConfigurationSettings> </Role> <Role name="fulltrust_workerrole"> <Instances count="1" /> <ConfigurationSettings /> </Role> </ServiceConfiguration> Web+WorkerIntegration using Queues Typical situation: Web Role: places messages in the queue. Worker Role: blocks on the queue waiting. Queuscan be scaled by offloading data to blobs or by using multiple queues. Input Queue (Work Items) Azure Queue 7

8 Web Role Writing to Queue if (!queue.doesqueueexist()) queue.createqueue(); Message msg = new Message(TextBox1.Text+"#"+TextB ox3.text); queue.putmessage(msg); Worker Role Reading from Queue StorageAccountInfo accountqueueinfo = StorageAccountInfo.GetDefaultQueueStorageA ccountfromconfiguration(); QueueStorage qs = QueueStorage.Create(accountQueueInfo); MessageQueue queue = qs.getqueue("customer"); while (true) { Message msg = queue.getmessage(); if (msg!= null) { // Process request } } 8

instance number and queues Example: Job Manager Input Queue (Work

9 Web+Worker Integration Example Input Queue (Work Items) Azure Queue Azure Queue Worker Role for Managing the Workflow: managing instance number and queues Example: Job Manager Input Queue (Work Items) Azure Queue Large Job Output Queues (Item done) Azure Queue 9

10 Internal vs. External Communication Endpoints Communication using Endpoints 10

11 Example: interaction with the Fabric Controller Next Time... Azure App Fabric Zookeeper Pig 11

Course Outline: Course 50466A: Windows Azure Solutions with Microsoft Visual Studio 2010

Course Outline: Course 50466A: Windows Azure Solutions with Microsoft Visual Studio 2010 Learning Method: Instructor-led Classroom Learning Duration: 3.00 Day(s)/ 24 hrs Overview: This class is an introduction