Sun believe that Cloud Computing (CC) is the next generation of network computing.
So, what is distinguish CC from previous models?
- It’s using information technology as a service over the network.
- We define it as a services that are encapsulated, have API, and available over the network
- It use both compute and storage resources as services
–> The predominant model for CC today is infrastructure as service or IaaS.
The Nature of Cloud Computing
CC incorporates virtualization, on-demand deployment, internet delivery as services and open source software. From one perspective, CC uses concepts, approaches and best practices that have already been establish; therefore, CC is nothing new. From another perspective, everything is new because CC changes the way we invent, develop, deploy, scale, update, maintain and pay for applications.
The on-demand, self-service, pay-by-use nature of CC is also an established trends.Virtualization is a key feature.
Services are delivered over the network. No mater where they are, no mater who they are; if they are authorized as employees, partners, suppliers, and consultants, applications can be made available anywhere, and at any time.
Cloud computing infrastructure models
There are 3 models that offer complementary benefits: public, private and hybrid clouds.These terms do not dictate location. While clouds are typically “out there” on Internet and private clouds are typically located on premises.
Public clouds provides services to multiple customers,a and is typically deployed at a colocation facility.
Private clouds may be hosted at a colocation facility or in an enterprise data center. They may be supported by the company, by a cloud provider, or by a third party such as an outsourcing firm.
Hybrid clouds combine both public and private cloud models, and they can be particularly effective when both types of cloud are located in the same facility
Architectural layers of cloud computing
Sun’s view of CC is using IT infrastructure as a service – and that service may be anything from renting raw hardware to using third-party APIs. In practice, services can be grouped into three categories: software as a service, platform as a service, and infrastructure as a service.
Software as a service (SaaS) features a complete application offered as a service on demand. A single instance of the software runs on the cloud and services multiple end users or client organizations. Salesforce.com, Google Doc… are examples of SaaS.
Platform as a service (PaaS) encapsulates a layer of software and provides it as a service
that can be used to build higher-level services. There are at least two perspectives on
PaaS depending on the perspective of the producer or consumer of the services:
- Someone producing PaaS might produce a platform by integrating an OS,
middleware, application software, and even a development environment that is
then provided to a customer as a service. For example, Netbeans, an integrated development environment, a Sun GlassFishTM Web stack and support for additional programming languages such as Perl or Ruby.
- Someone using PaaS would see an encapsulated service that is presented to them
through an API.
Commercial examples of PaaS include the Google Apps Engine, which serves applications on Google’s infrastructure.
Infrastructure as a service (IaaS) delivers basic storage and compute capabilities as
standardized services over the network. Servers, storage systems, switches, routers,
and other systems are pooled and made available to handle workloads that range
from application components to high-performance computing applications. Commercial examples of IaaS include Joyent, whose main product is a line of virtualized servers that provide a highly available on-demand infrastructure.
The benefits of CC is so big, such as reduce runtime and response time, minimize infrastructure risk, Lower cost, and increase pace of innovation. They are almost the same to the benefits of Grid Computing, the field I am studying.
From above, the predominant model for CC today is infrastructure as service or IaaS. So the next topic should be “Cloud computing, architecture of IaaS”.