Cloud Computing is defined as managing resources on the "cloud", i.e., remotely. Users can run their application without having to worry about all the hardware and software it uses. For instance, if you are hosting your website on a cloud, you don't have to worry about loads, uptime, server crashes etc. as they are all managed by the cloud host provider.
Benefits of Cloud Computing
Cloud computing offers a number of advantages. Cloud generally refers to the Internet, so that makes your applications more accessible and easy to manage online. You do not necessarily have to install any software or deploy any hardware at your side, all resources are provided by the service provider.Platform independence is one more virtue of Cloud Computing. There are more technical advantages of Cloud Computing such as not having to worry about load balancing, etc. which differ with service providers.
Types of Clouds
Based on accessibility, we can define four types of clouds as:
PUBLIC CLOUD
As the name suggests, public cloud refers to cloud systems that are easily accessible to the public. public cloud, however also runs the risk of security. example : Amazon Elastic Compute Cloud (EC2), Google AppEngine and Windows Azure Services Platform.
PRIVATE CLOUD
Private cloud restricts accessibility to only within an organization. It offers more security than a public cloud.
COMMUNITY CLOUD
Community cloud providers provide accessibility of cloud resources to a group of organizations of individuals.
HYBRID CLOUD
Hybrid cloud is a combination of public and private cloud services, allowing more flexibility to organisations, like using private cloud for their own organisation and public cloud for their applications.
Service Models
Cloud computing is categorized into three basic service models-
IaaS (Infrastructure as a Service) provides infrastructure, i.e., physical machines, virtual machines, virtual storage, etc.
PaaS (Platform as a Service) provides the platform, such as the runtime environment for applications, development and deployment tools, etc.
SaaS (Software as a Service) model provides software applications that are run on the client interface.
There is also Anything-as-a-Service (XaaS) model, which includes Network-as-a-Service, Business-as-a-Service, Identity-as-a-Service, Database-as-a-Service or Strategy-as-a-Service.
Disadvantages of Cloud Computing
Security and Privacy Issues
As already mentioned, public cloud is prone to security risks. The biggest concern is actually handing over sensitive data to a third party (like CSP - cloud service providers). Even though these services include security guarantees, it is risky to assume safety on the Internet.
Migrating to a different provider
Migrating from one CSP (Cloud Service Provider) to another is not hassle free. Largely, it involves transferring all applications which currently resided on specific platforms and hardware optimized and provided by one CSP to a different set of such specifications.
Characteristics of Cloud Computing
There are five key characteristics of cloud computing:
On Demand Self Service
Users have the power to access and manage resources online at any time, on-demand. For instance, one can log via the interface provided by the CSP (Cloud Service Provider) and access your services, such as defining the specific type of storage requirements, etc.
Broad Network Access
Cloud Computing provides this amazing power of mobility. You can access your services via any device with access points, any time and from anywhere. This feature not only helps customers to manage their applications on the go, it also helps them to run their business 24 X 7.
Resource Pooling
All the available resources (as per your service type) are pooled together so that anyone with the relevant authorization can be able to use them.
Rapid Elasticity
Cloud computing makes it very convenient for users to scale rapidly, both vertically and horizontally. You can add more users, increase or decrease resources at any time depending on your business needs.
Measured Service
Measured service refers to how your services are billed by your Cloud Service Provider. This of course varies with different providers and different plans. However, cloud computing services are reliably cheap, what with the savings over all the resources. Also, all the services that you use, for instance the bandwidth consumption per month, or storage requirements, or any other parameter can be easily measured.
Here's a cool infographic:
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| 5 characteristics of Cloud Computing |
