Lecture 15:�Cloud Computing

Modified from Mark Baker

What is Cloud Computing?

• Cloud Computing is a general term used to describe a new class of network based computing that takes place over the Internet,
• basically a step on from Utility Computing
• a collection/group of integrated and networked hardware, software and Internet infrastructure (called a platform).
• Using the Internet for communication and transport provides hardware, software and networking services to clients
• These platforms hide the complexity and details of the underlying infrastructure from users and applications by providing very simple graphical interface or API (Applications Programming Interface).

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What is Cloud Computing?

• In addition, the platform provides on demand services, that are always on, anywhere, anytime and any place.
• Pay for use and as needed, elastic
• scale up and down in capacity and functionalities
• The hardware and software services are available to
• general public, enterprises, corporations and businesses markets

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Cloud Summary

• Cloud computing is an umbrella term used to refer to Internet based development and services

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• A number of characteristics define cloud data, applications services and infrastructure:
• Remotely hosted: Services or data are hosted on remote infrastructure.
• Ubiquitous: Services or data are available from anywhere.
• Commodified: The result is a utility computing model similar to traditional that of traditional utilities, like gas and electricity - you pay for what you would want!

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Cloud Architecture

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What is Cloud Computing

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• Shared pool of configurable computing resources
• On-demand network access
• Provisioned by the Service Provider

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COMPUTER NETWORK

STORAGE (DATABASE)

SERVERS

SERVICES

APPLICATIONS

Adopted from: Effectively and Securely Using the Cloud Computing Paradigm by peter Mell, Tim Grance

Cloud Computing Characteristics

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Common Characteristics:

Low Cost Software

Virtualization

Service Orientation

Advanced Security

Homogeneity

Massive Scale

Resilient Computing

Geographic Distribution

Essential Characteristics:

Resource Pooling

Broad Network Access

Rapid Elasticity

Measured Service

On Demand Self-Service

Adopted from: Effectively and Securely Using the Cloud Computing Paradigm by peter Mell, Tim Grance

Cloud Service Models

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Software as a Service (SaaS)

Platform as a Service (PaaS)

Infrastructure as a Service (IaaS)

SalesForce CRM

LotusLive

Adopted from: Effectively and Securely Using the Cloud Computing Paradigm by peter Mell, Tim Grance

SaaS Maturity Model

Level 2: Configurable per customer

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Source: Frederick Chong and Gianpaolo Carraro, “Architectures Strategies for Catching the Long Tail”

Level 3: configurable & Multi-Tenant-Efficient

Level 1: Ad-Hoc/Custom – One Instance per customer

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Level 4: Scalable, Configurable & Multi-Tenant-Efficient

Different Cloud Computing Layers‏

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Cloud Computing Service Layers

Description

Services – Complete business services such as PayPal, OpenID, OAuth, Google Maps, Alexa

Services

Application

Focused

Infrastructure

Focused

Application – Cloud based software that eliminates the need for local installation such as Google Apps, Microsoft Online

Storage – Data storage or cloud based NAS such as CTERA, iDisk, CloudNAS

Development – Software development platforms used to build custom cloud based applications (PAAS & SAAS) such as SalesForce

Platform – Cloud based platforms, typically provided using virtualization, such as Amazon ECC, Sun Grid

Hosting – Physical data centers such as those run by IBM, HP, NaviSite, etc.

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Basic Cloud Characteristics

• The “no-need-to-know” in terms of the underlying details of infrastructure, applications interface with the infrastructure via the APIs.
• The “flexibility and elasticity” allows these systems to scale up and down at will
• utilising the resources of all kinds
• CPU, storage, server capacity, load balancing, and databases
• The “pay as much as used and needed” type of utility computing and the “always on!, anywhere and any place” type of network-based computing.

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Basic Cloud Characteristics

• Cloud are transparent to users and applications, they can be built in multiple ways
• branded products, proprietary open source, hardware or software, or just off-the-shelf PCs.
• In general, they are built on clusters of PC servers and off-the-shelf components plus Open Source software combined with in-house applications and/or system software.

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Software as a Service (SaaS)

• SaaS is a model of software deployment where an application is hosted as a service provided to customers across the Internet.
• Saas alleviates the burden of software maintenance/support
• but users relinquish control over software versions and requirements.
• Terms that are used in this sphere include
• Platform as a Service (PaaS) and
• Infrastructure as a Service (IaaS)

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Virtualization

• Virtual workspaces:
• An abstraction of an execution environment that can be made dynamically available to authorized clients by using well-defined protocols,
• Resource quota (e.g. CPU, memory share),
• Software configuration (e.g. O/S, provided services).
• Implement on Virtual Machines (VMs):
• Abstraction of a physical host machine,
• Hypervisor intercepts and emulates instructions from VMs, and allows management of VMs,
• VMWare, Xen, etc.
• Provide infrastructure API:
• Plug-ins to hardware/support structures

Virtual Machines

• VM technology allows multiple virtual machines to run on a single physical machine.

Hardware

Virtual Machine Monitor (VMM) / Hypervisor

Guest OS

(Linux)

Guest OS

(NetBSD)

Guest OS

(Windows)

App

App

App

App

App

Xen

VMWare

UML

Denali

etc.

Performance: Para-virtualization (e.g. Xen) is very close to raw physical performance!

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Virtualization in General

• Advantages of virtual machines:
• Run operating systems where the physical hardware is unavailable,
• Easier to create new machines, backup machines, etc.,
• Software testing using “clean” installs of operating systems and software,
• Emulate more machines than are physically available,
• Timeshare lightly loaded systems on one host,
• Debug problems (suspend and resume the problem machine),
• Easy migration of virtual machines (shutdown needed or not).
• Run legacy systems!

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What is the purpose and benefits?

• Cloud computing enables companies and applications, which are system infrastructure dependent, to be infrastructure-less.
• By using the Cloud infrastructure on “pay as used and on demand”, all of us can save in capital and operational investment!
• Clients can:
• Put their data on the platform instead of on their own desktop PCs and/or on their own servers.
• They can put their applications on the cloud and use the servers within the cloud to do processing and data manipulations etc.

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Cloud-Sourcing

• Why is it becoming a Big Deal:
• Using high-scale/low-cost providers,
• Any time/place access via web browser,
• Rapid scalability; incremental cost and load sharing,
• Can forget need to focus on local IT.
• Concerns:
• Performance, reliability, and SLAs,
• Control of data, and service parameters,
• Application features and choices,
• Interaction between Cloud providers,
• No standard API – mix of SOAP and REST!
• Privacy, security, compliance, trust…

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Some Commercial Cloud Offerings

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Cloud Taxonomy

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Cloud Storage

• Several large Web companies are now exploiting the fact that they have data storage capacity that can be hired out to others.
• allows data stored remotely to be temporarily cached on desktop computers, mobile phones or other Internet-linked devices.

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• Amazon’s Elastic Compute Cloud (EC2) and Simple Storage Solution (S3) are well known examples
• Mechanical Turk

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Amazon Simple Storage Service (S3)

• Unlimited Storage.
• Pay for what you use:
• $0.20 per GByte of data transferred,
• $0.15 per GByte-Month for storage used,
• Second Life Update:
• 1TBytes, 40,000 downloads in 24 hours - $200,

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Utility Computing – EC2

• Amazon Elastic Compute Cloud (EC2):
• Elastic, marshal 1 to 100+ PCs via WS,
• Machine Specs…,
• Fairly cheap!
• Powered by Xen – a Virtual Machine:
• Different from Vmware and VPC as uses “para-virtualization” where the guest OS is modified to use special hyper-calls:
• Hardware contributions by Intel (VT-x/Vanderpool) and AMD (AMD-V).
• Supports “Live Migration” of a virtual machine between hosts.
• Linux, Windows, OpenSolaris
• Management Console/AP

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EC2 – The Basics

• Load your image onto S3 and register it.
• Boot your image from the Web Service.
• Open up required ports for your image.
• Connect to your image through SSH.
• Execute you application…

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Opportunities and Challenges

• The use of the cloud provides a number of opportunities:
• It enables services to be used without any understanding of their infrastructure.
• Cloud computing works using economies of scale:
• It potentially lowers the outlay expense for start up companies, as they would no longer need to buy their own software or servers.
• Cost would be by on-demand pricing.
• Vendors and Service providers claim costs by establishing an ongoing revenue stream.
• Data and services are stored remotely but accessible from “anywhere”.

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Opportunities and Challenges

• In parallel there has been backlash against cloud computing:
• Use of cloud computing means dependence on others and that could possibly limit flexibility and innovation:
• The others are likely become the bigger Internet companies like Google and IBM, who may monopolise the market.
• Some argue that this use of supercomputers is a return to the time of mainframe computing that the PC was a reaction against.
• Security could prove to be a big issue:
• It is still unclear how safe out-sourced data is and when using these services ownership of data is not always clear.
• There are also issues relating to policy and access:
• If your data is stored abroad whose policy do you adhere to?
• What happens if the remote server goes down?
• How will you then access files?
• There have been cases of users being locked out of accounts and losing access to data.

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Advantages of Cloud Computing

• Lower computer costs:
• You do not need a high-powered and high-priced computer to run cloud computing's web-based applications.
• Since applications run in the cloud, not on the desktop PC, your desktop PC does not need the processing power or hard disk space demanded by traditional desktop software.
• When you are using web-based applications, your PC can be less expensive, with a smaller hard disk, less memory, more efficient processor...
• In fact, your PC in this scenario does not even need a CD or DVD drive, as no software programs have to be loaded and no document files need to be saved.

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Advantages of Cloud Computing

• Improved performance:
• With few large programs hogging your computer's memory, you will see better performance from your PC.
• Computers in a cloud computing system boot and run faster because they have fewer programs and processes loaded into memory…
• Reduced software costs:
• Instead of purchasing expensive software applications, you can get most of what you need for free-ish!
• most cloud computing applications today, such as the Google Docs suite.
• better than paying for similar commercial software
• which alone may be justification for switching to cloud applications.

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Advantages of Cloud Computing

• Instant software updates:
• Another advantage to cloud computing is that you are no longer faced with choosing between obsolete software and high upgrade costs.
• When the application is web-based, updates happen automatically
• available the next time you log into the cloud.
• When you access a web-based application, you get the latest version
• without needing to pay for or download an upgrade.

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• Improved document format compatibility.
• You do not have to worry about the documents you create on your machine being compatible with other users' applications or OSes
• There are potentially no format incompatibilities when everyone is sharing documents and applications in the cloud.

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Advantages of Cloud Computing

• Unlimited storage capacity:
• Cloud computing offers virtually limitless storage.
• Your computer's current 1 Tbyte hard drive is small compared to the hundreds of Pbytes available in the cloud.
• Increased data reliability:
• Unlike desktop computing, in which if a hard disk crashes and destroy all your valuable data, a computer crashing in the cloud should not affect the storage of your data.
• if your personal computer crashes, all your data is still out there in the cloud, still accessible
• In a world where few individual desktop PC users back up their data on a regular basis, cloud computing is a data-safe computing platform!

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Advantages of Cloud Computing

• Universal document access:
• That is not a problem with cloud computing, because you do not take your documents with you.
• Instead, they stay in the cloud, and you can access them whenever you have a computer and an Internet connection
• Documents are instantly available from wherever you are
• Latest version availability:
• When you edit a document at home, that edited version is what you see when you access the document at work.
• The cloud always hosts the latest version of your documents
• as long as you are connected, you are not in danger of having an outdated version

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Advantages of Cloud Computing

• Easier group collaboration:
• Sharing documents leads directly to better collaboration.
• Many users do this as it is an important advantages of cloud computing
• multiple users can collaborate easily on documents and projects
• Device independence.
• You are no longer tethered to a single computer or network.
• Changes to computers, applications and documents follow you through the cloud.
• Move to a portable device, and your applications and documents are still available.

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Disadvantages of Cloud Computing

• Requires a constant Internet connection:
• Cloud computing is impossible if you cannot connect to the Internet.
• Since you use the Internet to connect to both your applications and documents, if you do not have an Internet connection you cannot access anything, even your own documents.
• A dead Internet connection means no work and in areas where Internet connections are few or inherently unreliable, this could be a deal-breaker.

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Disadvantages of Cloud Computing

• Does not work well with low-speed connections:
• Similarly, a low-speed Internet connection, such as that found with dial-up services, makes cloud computing painful at best and often impossible.
• Web-based applications require a lot of bandwidth to download, as do large documents.
• Features might be limited:
• This situation is bound to change, but today many web-based applications simply are not as full-featured as their desktop-based applications.
• For example, you can do a lot more with Microsoft PowerPoint than with Google Presentation's web-based offering

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Disadvantages of Cloud Computing

• Can be slow:
• Even with a fast connection, web-based applications can sometimes be slower than accessing a similar software program on your desktop PC.
• Everything about the program, from the interface to the current document, has to be sent back and forth from your computer to the computers in the cloud.
• If the cloud servers happen to be backed up at that moment, or if the Internet is having a slow day, you would not get the instantaneous access you might expect from desktop applications.

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Disadvantages of Cloud Computing

• Stored data might not be secure:
• With cloud computing, all your data is stored on the cloud.
• The questions is How secure is the cloud?
• Can unauthorised users gain access to your confidential data?
• Stored data can be lost:
• Theoretically, data stored in the cloud is safe, replicated across multiple machines.
• But on the off chance that your data goes missing, you have no physical or local backup.
• Put simply, relying on the cloud puts you at risk if the cloud lets you down.

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Disadvantages of Cloud Computing

• HPC Systems:
• Not clear that you can run compute-intensive HPC applications that use MPI/OpenMP!
• Scheduling is important with this type of application
• as you want all the VM to be co-located to minimize communication latency!
• General Concerns:
• Each cloud systems uses different protocols and different APIs
• may not be possible to run applications between cloud based systems
• Amazon has created its own DB system (not SQL 92), and workflow system (many popular workflow systems out there)
• so your normal applications will have to be adapted to execute on these platforms.

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The Future

• Many of the activities loosely grouped together under cloud computing have already been happening and centralised computing activity is not a new phenomena
• Grid Computing was the last research-led centralised approach
• However there are concerns that the mainstream adoption of cloud computing could cause many problems for users
• Many new open source systems appearing that you can install and run on your local cluster
• should be able to run a variety of applications on these systems

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