Evolution - not revolutionServer resources are shared globally instead of locally• Excess capacity for peak

usage can be shared• Backup, security and other

common functions can be shared

• Failover is part of the underlying infrastructure

Integration of existing technologies

Virtualization, Internet, databases, etc. have all been around for many years

Many companies have already outsourced their IT infrastructure

Much of the Cloud can be seen as just another form of outsourcing – issues such as SLA, uptime, security are similar or identical

Broadband is the enabler that has made the Cloud possible

Classification of Cloud Computing 1

By location

• PublicInfrastructure is hosted by Cloud vendor and shared with other

tenantsLowest cost and lowest security

• PrivateInfrastructure is not shared; may be on-premises or hosted externally Increased cost and increased security

• HybridBoth Private and Public Cloud services used together, perhaps to retain critical data on-premisesCloud Bursting – Private Cloud with Public Cloud to cover peak usage (not to be confused with IBM’s CloudBurst appliance).

• CommunityLies between Public and Private; a group of organisations (within the public sector for example) with similar requirements share a single CloudSimilar to externally hosted Private Cloud, but with more than one tenant

Classification of Cloud Computing 2By service provided

• IaaS – Infrastructure as a ServiceHardware related services using the principles of cloud computingA platform for running virtual servers, either vendor supplied images or created by the customer.Database services, IP addresses and persistent storage may also be offered.Normally billed by CPU cycles, storage usage, network traffic etc. Amazon’s EC2 and S3 are good examples.

• PaaS – Platform as a ServiceA development platform in the Cloud, may be thought of as a virtual web/application server.Billed as for IaaS.Google’s App Engine, Microsoft’s Azure, Salesforce’s force.com.

• SaaS – Software as a ServiceEmail, Office, CRM etc. services offered on a pay-per-user basis.Microsoft’s BPOS and Web Office, Google’s Google Docs and Gmail, IBM’s LotusLive, Salesforce’s CRM solution.

Example – Amazon Web Services AWSInfrastructure as a Service

• Originally created by Amazon for their own e-commerce site, it is now a major revenue earner for the company with a estimated margin of around 50%.• Powers many Facebook games as well as organisations such as Netflix, NASA, Autodesk, NASDAQ and the New York Times.• Many different components are available, the two most important are the EC2 (Elastic Computing Cloud) and the S3 (Simple Storage Service, 99.999999999% redundancy).• Virtual private server instances known as Amazon Machine Images are run on EC2. Linux, Solaris and Windows Server virtual machines are available.• S3 or Amazon’s database services (e.g. MySQL, Oracle) can be accessed by the AMIs or by external applications•The AWS API has become something of a standard,with GPL products such as Eucalyptus and NASA’s Nebulausing the API.• A high performance option is available

At its most basic, an application running on the AWS may consist of a virtual server running on the EC2, storage in the S3 and perhaps a message queue running on the Simple Queue Service (SQS).

Example – SalesforceSince 1999, one of the early Cloud players. Originally a Internet based CRM application; still has a focus on customer relationships and service but has diversified into both Platform and Infrastructure offerings.

• Tightly integrated with Social Networks such as Facebook and Twitter.

• Tightly integrated with the Google Data APIs – can access Google’s Calendar, Docs and Gmail• directly.• Integration with Outlook via Outlook Connector; does not yet support Windows 7 or Office 2010 and no resolution date given.

• Sales support, service support and collaboration applications available.

• Sector specific versions of applications available.

• Salesforce AppExchange is a marketplace for Salesforce applications and services. Contains 965 apps and 292 services at the present time.

A few aspects of the CloudAgility – implementation of new services no longer needs to deal with hardware issues. Services can be brought on-line quicker.

Cost – capital costs are converted to operational costs and can follow usage as capacity need not be purchased until needed. Economies of scale can be leveraged in a shared Cloud as common services – such as backup & restore, virus searching, fail-over – are also shared.

Device and location independence – connection to the Internet allows services to be accessed anywhere there is a connection and using any device with a suitable client.

Multi-tenancy – a key characteristic of the Cloud, enables sharing of resources and costs across a large pool of users.

Reliability – is improved if multiple redundant sites are part of the Cloud infrastructure.

Scalability – also part of the Cloud infrastructure but may require attention to parallel programming when developing applications to take full advantage of the platform.

Security – issues as well as advantages. The Cloud vendor is able to devote resources to security that many customers can not afford, logs and audits are standard. However there are legal issues related to the physical location of data (e.g. the Patriot Act for data hosted in the USA), as well as more normal security issues. Systems are no longer behind a corporate firewall, extra complexity increases risk of errors, multi-tenancy allows for the possibility of data becoming available for other organisations, etc. Data security is common area of concern for potential customers.

Metering and quota management – normally part of the Cloud infrastructure, vendors track space, CPU cycles etc for billing purposes

SLA – same issues apply here as for ‘old fashioned’ outsourcing; total uptime, solution time in the case of problems, etc.

New ways of thinking and new risks

Resource sharing allows the emergence of the Cloud model• On Demand computer resources – pay-per-use billing model• Little or no capital expenditure required• Long term commitment is not necessary• Computing as a commodity – buy computer resources on an open

market

New or increased risks need to be dealt with• Security

• Is my data safe from hackers or spies? (Is it any less safe than outsourced data?)

• Should I keep a local copy or backup of my data?

• Availability • What happens if the Internet is down?• What happens if my vendor is taken over or goes bankrupt?

• Standards and interoperability• Will I become locked in to a specific vendor?• Can I use different vendors/platforms in my cloud solution?