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Wednesday, 3 February 2016

Cloud Computing

What is Cloud????

Typically, a term "cloud" means hiding complexities of technical processes from end users that are required to provision services from cloud.  Just like, if you look at the sky like in above image, you will not be able to see if any plane is flying above the clouds.

End user may not be a technical person and has no idea on how to work with cloud services to provision the same.

Cloud has 2 major stakeholders as Cloud provider and Cloud consumer. Provider is the Cloud services provider and Consumer means end user (Individuals/Organizations) who will be using the cloud services.

Instead of defining cloud, we will note down the characteristics of cloud as multiple cloud vendors have their own definitions of cloud. These characteristics are applicable for all types of cloud.

Cloud has below characteristics:
  • Internet based compute model
  • Security
  • Rapid provisioning
  • Elasticity
  • Ubiquitous
  • Pay as you go model
  • On-demand resource access
What does cloud provide?

Cloud services has 3  fundamental models for provisioning with different subscription models.
  • SaaS
  • PaaS
  • IaaS 
Now a days you may also come across terms as DaaS (Desktop as a Service), ITaaS (IT as a Service) as well.

Before I explain what do we mean by SaaS, PaaS, and IaaS let us see the layers of computer system.

Every computer System has 3 layers in its architecture.
  • Application
  • Operating System
  • Hardware
Below image shows these layers in physical system as well as Virtual machine.

Image: VMware
SaaS (Software as a Service):

Software as a service (SaaS) one of the method of delivering applications over the Internet—as a service. End users (Individuals/organizations) do not need to install and maintain software, instead they access it via the Internet, therefore relief from complex software and hardware management. 

PaaS (Platform as a Service):

In Platform as a service (PaaS) model that delivers applications over the Internet. In a PaaS model, a cloud provider delivers hardware and applications to its users as a service. A PaaS provider hosts the hardware and software on its own infrastructure. 

End Users do not need to install in-house hardware and software to develop or run a new application.  

IaaS (Infrastructure as a Service):

In an IaaS model, a third-party provider hosts hardware, software, servers, storage and other infrastructure components on behalf of its users. IaaS providers also host users' applications and handle tasks including system maintenance, backup and resiliency planning. 


Types of Cloud:

There are 3 types of Cloud provisionings as below. 
  • Public cloud
  • Private cloud
  • Hybrid Cloud

Public Cloud:

The public cloud is also called as a multi-tenant environment. In public cloud, a service provider makes resources, such as applications, available to the general public over the Internet. 

In a nutshell, you can also say that underlying datacenter resources are shared by multiple consumers (typically different organizations) with logical separation between them for security purpose as shown in below diagram

Examples of Public clouds are vCloud Air from VMware, Azure from Microsoft.

Private Cloud:

Private cloud computing delivers similar advantages to that of public cloud, but through a proprietary architecture. This is also called as single tenant environment. Unlike public clouds, in which delivery of cloud services is to multiple organizations, a private cloud is dedicated to a single organization.

Organization further may divide the cloud resources based on different metrics like departments, geographical offices. Private cloud can be implemented by any organization with the help of products like vRealize Automation from VMware. Below is the example of private cloud build behind the firewall by an organization, however private cloud can also be opted from third party provider. 


Hybrid Cloud:

In hybrid cloud compute design, Consumer uses both private and public cloud services. Basically, we provide visibility between private and public cloud infrastructures with the help of cloud component like cloud connector. This allows organizations to move their workloads from private to public and vice versa in the event like planned maintenance. 


.Please feel free to comment if have any feedback or discussion point.


  1. Good job... You will reach to places in future....

  2. This comment has been removed by the author.

  3. Hey, I appreciate to your writing.

  4. This comment has been removed by the author.



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