Cloud Computing = Software as a Service (SaaS)+ Platform as a Service (PaaS)+ Infrastructure as a Service (IaaS)
Cloud Computing Service Models:
1) IaaS (Infrastructure as a Service):
- Delivers computer infrastructure, typically a platform virtualization environment as a service.
- Cloud providers build datacenters, managing power, scale, hardware, networking, storage, distributed system, etc…
- Rather than purchasing servers, software, data center space or network equipment, clients instead buy those resources fully outsourced service.
- Eg: Amazon Web Services(AWS), Rackspace Hosting, VMWare, Citrix, Azure
2) PaaS (Platform as a Service):
- Provides developer’s necessary tools to create, test, host and maintain created applications.
- Cloud providers offer an Internet-based platform to developers who create services but don’t want to build their own cloud.
- Ex: Microsoft Azure, Google App, AWS
3) SaaS (Software as a Service):
- SaaS is a software delivery methodology that provides licensed multi-tenant access to software and its functions remotely as a Web-based service.
- From the end, user’s point of view apps are locat in the cloud and it is almost always accessible through a web browser.
- Any application hosted on a remote server can be access over the Internet is considered as SaaS.
- Usually billed based on usage and a multi-tenant environment.
- Ex: Microsoft Azure, Gmail, Google Apps (Office-like features), Sales Force CRM
Deployment Models in Cloud Computing
There are three main deployment models in Cloud Computing.
- These are the clouds which are open for use by general public and they exist beyond the firewall of an organization, fully hosted and managed by vendors.
- Your data stored in the provider’s data center and the provider responsible for the management and maintenance of the data center.
- Note: Even though you don’t control the security of a public cloud, all of your data remains separate from others and security breaches of public clouds are extremely rare.
- Cons: They are more vulnerable than private clouds and there is no control of resources used or who shares them.
- This type of cloud environment is appealing to many companies because it reduces lead times in testing and deploying new products.
- This is a good option if your demand for computing resources fluctuates. You have to purchase the capacity on the basis of usage and can scale up or scale down server capabilities based on traffic and other dynamic requirements.
- you are sharing computing resources among a network of users, the public cloud offers greater flexibility and cost savings.
- A private cloud hosting solution, also known as an internal or enterprise cloud, resides on company’s intranet or hosted data center where all of your data is protectes behind a firewall.
- This can be a great option for companies who already have expensive data centers they can use their current infrastructure.
- You go for a private cloud when you have strict security and data privacy
Cons: The main drawback people see with a private cloud is that all management, maintenance, and updating of data centers is the responsibility of the company.
- They consist of external and internal providers, namely a mix of public and private clouds.
- Secure & critical apps are managed by an organization and the not-so-critical & secure apps by the third party vendor.
- For example, you can use the public cloud to interact with the clients but keep their data secured within a private cloud. Most companies are now switching to Hybrid clouds.
- Ideal in situations where you have plans are to migrate to a complete cloud solution as existing hardware expires or you have some applications or hardware that are not ready for the cloud.