Cloud Service Delivery Models

Infrastrucutre as a service: offers storage and compte resources that developers and IT organizations use to deliver custom business solutions.

Platform as a service: offers development envioronments ath atIT organzations can use to creatse cloud-rready business applications

Software as a service: offers purpose built business applications


Infrastructure - as a Service
This refers to teh delivery of computer hardware - including Servers, networking technology, storage and data centre space), as a service. It may also include the delivery of operating systems and virtualization technlogy to manage the resources

Customers can rent computing resources instead of buying and installing them in their own data centres. (it's typically a pay as you use model). the service may incldue dynamic scaling - (bursting up or scaling down).

Key Example - Amazon's EC2 (Elastic Cloud - IaaS)

Organizations can "rent" computing resources - to boost their data centers by renting computer hardware adn appropriate allocations os sservers, networking technloogy, sotrate an data centre space - as a service, instead of laying out the capital expenditure for the maximum amount of resources to cover their highest level of demand, they purchase computing power if and when they ned it.


Platform as a Service
teh platform provider delivers more than infrastructure. It delivers a solutions stack - integrated set of software that profides everthign a developerneeds to build an applicationf for both sofware deevelopment and runtime.

This is an evolution of Web hosting. PaaS - provies lifeecyle managment capabillitys to manage all software delovelopment stages from plannig and design to building and deployment to testinga nd maintenance.

Key benefit: customers can haev sofware development anddeployment capabillity based entirely int he cloud. No mgt or maintenance efforts are reeqired for teh infrastructure.
all aspects of software develoment exist in the cloud. From design stage to build ing adn deployment - everything lives in the cloud.

Key Caveat: PaaS offerings have proprietary elements - so customers are tied to their PaaS providers adn may face high expenses if they choose to switch.


Software as a Service
This phenomenon refers to business applicatons that are hosted by the provider and delivered as a service.


Application Service Providers and CRM applications are the most common categories of Software as a service. (key example - Salesforce.com).

Advantages: Price of the software is on a per-use baseis, adn invoves no upfront costs from teh service provdier.

initially SaaS offerngs were not implemented over the internet. For the same oof security adn reliability , these offerings woudl normally involve virtual private networks.

Management & Administration - as a factor of cloud computing models.

Cloud computing services are easy enough to explain conceptually - however in implementing cloud services, one has to integrate it into the IT operations of the organization.


Note: Becuaes cloud requires a sel=service capability, it must be edesigned to manage not just provisionoing customer reqeusts but also issues sucah as workload managment, security, meteriing, monitoring and billing services.

For cloud serivces to be safe adn effective, they must measure and monijtor performance.