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Cloud computing The three-tier architectural style & Google AppEngine Some material adapted from slides by Indranil Gupta, Jimmy Lim, Christophe Bisciglia, Aaron Kimball, & Sierra Michels-Slettvet, Google Distributed Computing Seminar, (licensed under Creation Commons Attribution 3.0 License)

“No less influential than e-business” (Gartner, 2008) “Cloud computing achieves a quicker return on investment “ (Lindsay Armstrong of salesforce.com, Dec 2008) “ Economic downturn, the appeal of that cost advantage will be greatly magnified" (IDC, 2008) “Revolution, the biggest upheaval since the invention of the PC in the 1970s […] IT departments will have little left to do once the bulk of business computing shifts […] into the cloud” (Nicholas Carr, 2008) “ Not only is it faster and more flexible, it is cheaper. […] the emergence of cloud models radically alters the cost benefit decision “ (FT Mar 6, 2009) The economics are compelling, with business applications made three to five times cheaper and consumer applications five to 10 times cheaper (Merrill Lynch, May, 2008) 3

“Cloud computing is simply a buzzword used to repackage grid computing and utility computing, both of which have existed for decades.” whatis.com Definition of Cloud Computing 5

“The interesting thing about cloud computing is that we’ve redefined cloud computing to include everything that we already do. […] The computer industry is the only industry that is more fashion-driven than women’s fashion. Maybe I’m an idiot, but I have no idea what anyone is talking about. What is it? It’s complete gibberish. It’s insane. When is this idiocy going to stop?” “The interesting thing about cloud computing is that we’ve redefined cloud computing to include everything that we already do. […] The computer industry is the only industry that is more fashion-driven than women’s fashion. Maybe I’m an idiot, but I have no idea what anyone is talking about. What is it? It’s complete gibberish. It’s insane. When is this idiocy going to stop?” Larry Ellison During Oracle’s Analyst Day From 6

Are we here today ? * From 7

What is Cloud Computing?

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10 Steady CAPEX spend Global Annual Server Spending (IDC) Source: IBM Corporate Strategy analysis of IDC data Uncontrolled management and energy costs To make progress, delivery organizations must address the server, storage and network operating cost problem, not just CAPEX $0B New system spend Management and admin costs Power and cooling costs

11  A new consumption and delivery model inspired by consumer Internet services.  Private, Public and Hybrid  Workload and/or Programming Model Specific  The Industrialization of Delivery for IT supported Services Cloud Services Cloud Computing Model  Self-service  Sourcing options  Economies-of-scale Multiple Types of Clouds will co-exist: “Cloud” represents: Cloud enables:“Cloud” is:

Cloud computing: a new consumption and delivery model inspired by consumer Internet services. 5 key characteristics: On-demand self-service Ubiquitous network access Location independent resource pooling Rapid elasticity Pay per use While the technology is not new, the end user focus of self-service, self-management leveraging these technologies is new. Virtualization Service Automation Usage Tracking Web 2.0 End User Focused

13  A new consumption and delivery model inspired by consumer Internet services.  Private, Public and Hybrid  Workload and/or Programming Model Specific  The Industrialization of Delivery for IT supported Services Cloud Services Cloud Computing Model  Self-service  Sourcing options  Economies-of-scale Multiple Types of Clouds will co-exist: “Cloud” represents: Cloud enables:“Cloud” is:

Key Technology: Virtualization Hardware Operating System App Traditional Stack Hardware OS App Hypervisor OS Virtualized Stack Hardware JVM App OS/JVM Managent JVM Virtualized Stack

Enterprise Mutiple primary delivery models companies are implementing for cloud Public Cloud IT activities/functions are provided “as a service,” over the Internet  Key features:  Scalability  Automatic/rapid provisioning  Standardized offerings  Consumption-based pricing.  Multi-tenancy Traditional Enterprise IT Private Cloud IT activities/functions are provided “as a service,” over an intranet, within the enterprise and behind the firewall  Key features include:  Scalability  Automatic/rapid provisioning  Chargeback ability  Widespread virtualization Private Cloud Public Clouds Hybrid Cloud Source: IBM Market Insights, Cloud Computing Research, July 2009.

Different Computing Models  Infrastructure as a service (IaaS)  Utility computing  Why buy machines when you can rent cycles?  Examples: Amazon’s EC2, GoGrid, AppNexus  Platform as a Service (PaaS)  Give me nice API and take care of the implementation  Example: Google App Engine  Software as a Service (SaaS)  Just run it for me!  Example: Gmail

Virtualized environments only get benefits of scale if they are highly utilized Drives lower capital requirements More complexity = less automation possible = people needed Take repeatable tasks and automate Labor Leverage Infrastructure Leverage Clients who can “serve themselves” require less support and get services Self Service Automation of Management Standardization of Workloads Virtualization of Hardware Utilization of Infrastructure

Server/Storage Utilization 10-20% Self serviceNone Test Provisioning Weeks Change Management Months Release Management Weeks Metering/Billing Fixed cost model Payback period for new services Years 70-90% Unlimited Minutes Days/Hours Minutes Granular Months Legacy environmentsCloud enabled enterprise Cloud accelerates business value across a wide variety of domains. CapabilityFromTo

 Marc Benioff, head of salesforce.com  “Cloud computing isn't just candyfloss thinking – it's the future. If it isn't, I don't know what is. We're in it. You're going to see this model dominate our industry."  Is data really safe in the cloud? "All complex systems have planned and unplanned downtime. The reality is we are able to provide higher levels of reliability and availability than most companies could provide on their own," says Benioff

 John Chambers, Cisco Systems’ CEO  "a security nightmare.”

Push factors  Fluctuating demand  Highly standardized applications  Modular, independent applications  Unacceptably high costs Barriers  Data privacy or regulatory and compliance issues  High level of Internal control required  Accessibility and reliability are a concern  Cost is not a concern Source: IBM Market Insights, Cloud Computing Research,

 Trade-off is value vs. risk of migration  Workload characteristics are critical  New workloads will emerge as cloud makes them affordable (eg pervasive analytics, Smart Healthcare)

Three-tier architectures and Google AppEngine

Levels of abstraction  Different levels of abstraction  Instruction Set VM: Amazon EC2  ApplicationLevel VM: Google AppEngine  Similar to languages  Higher level abstractions can be built on top of lower ones EC2AzureAppEngine Force.com Lower-level, More flexibility, More management Not scalable by default Higher-level, Less flexibility, Less management Automatically scalable 25

 Separation of concerns: Presentation, business and data handling logic are clearly partitioned in different tiers.  Synchronous communications: Communications between tiers is synchronous request-reply. Each tier waits for a response from the other tier before proceeding.  Flexible deployment: There are no restrictions on how a multi- tier application is deployed. All tiers could run on the same machine, or each tier may be deployed on its own machine. Databases Application Logic Web Server / Presentation Logic Web Client Web Client Web Client Tier Web Server Tier Business Logic Tier Data Management Tier

BigTable (your) Java / Python hosted application / Presentation Logic Web Client Web Client Web Client Tier Web Server Tier Business Logic Tier Data Management Tier Hosting Server

 Simplified (Web Application) development (for a part of the application lifecycle)  by leveraging Google infrastructure ▪ Scalability ▪ Reliability ▪ Functionality

Simplified (Web Application) development  Implementation ▪ Simplified/integrated application monitoring and logging ▪ Simplified user authentication ▪ Tooling  Deployment / maintenance / and use ▪ No servers to setup – Apache, EJB containers, database ▪ No server management / monitoring / upgrade ▪ Billing model: Pay per use ▪ Reduced upfront investment ▪ [Promise of] scalability ▪ Monitoring and statistics ▪ User authentication

 Differentiate between requests for static and dynamic content.

 Defining static content

 Runs your code (e.g., servlet)  Restricted JVM environment ▪ Threads, security manager, file-access read only, new connections, reflection  Enforces Isolation  Keeps apps safe from each other  Many applications, many concurrent requests ▪ Smaller footprint  Stateless!  Allows for scheduling flexibility  Time bound!  Service API requests to access to other services

Use APIs to do things you don't want to do in your runtime, such as... Calls are blocking!

 Across requests  Session  Memcache  Datastore

 Based on BigTable   Replicated and fault tolerant  On commit: ≥3 machines  Geographically distributed  No relational model!  New API.

 Benefits ▪ Scalability ▪ No machines to manage ▪ Integrated development/production environment ▪ Tools: admin console, logging ▪ Easy deployment  Some restrictions ▪ Small request footprint (implicit) ▪ Fast requests ▪ Stateless requests ▪ Schemaless data model ▪ [understand their impact and the reasons they were added]

 AppEngine: specialized platform for Web Applications  unfit for general computing.  Support for part of lifecycle of a web application  Offers transparent access to scalable infrastructure  You pay a price for the ‘infinite’ scalability offered: constrains on your application ▪ Requests have to explicitly fetch state, schemaless data models, limits on resource usage for each request.