IaaS VS PaaS Vs SaaS - Differences And Explanation Of Cloud Service Models


In this article, I am going to explain IaaS, PaaS, and SaaS cloud service models. This article is for beginners, intermediate, and professionals.

What is Cloud Computing?

Let’s discuss the below traditional scenario before we start.
Suppose we are planning to start a small e-commerce company/website. We need to set up the below environment before our company/website goes live,
  • Hardware like Server, RAM, Router, Load balance, etc
  • Licence Operating System or Software.
  • Data Center to manage data.
  • IT people to implement and manage things.
We need to set up below infrastructures on the premises.
To set up the above infrastructures on-premises, we need to invest lots of money right?
Now we will think of the below two scenarios,
  1. The company works well – In this case, we need to scale up our hardware/infrastructure to support our customers.
  2. The company is not doing well – In this case, we will lose our money which has been invested in hardware, software, data center, IT professional, etc.

How will you solve this problem?

The practically new company doesn’t want to spend lots of money to buy new infrastructures/ set up an environment or recruit IT professionals.
Do they want someone who will handle all hardware, software, datacenters, and maintenance for them? That’s where a cloud company comes in picture.
Cloud computing provides a “Pay per use” facility.
To understand “Pay per use”, take an example of a hotel. In a hotel you pay for what you eat; similarly, in the cloud you pay for what you have used.
In simple words, cloud computing is a different service provider on the internet and you will pay for the services which you have used.
Today many cloud service provider available in the market, a few of them are,
  1. Amazon web services
  2. Microsoft Azure
  3. Google Cloud
  4. IBM Cloud
  5. Salesforce
  7. Sun etc
Suppose we want to move our company/E-commerce website on the cloud, we need Hardware, Software, and Data Centers, etc. So we need many resources or services to go live right?
Cloud has divided these services into 3 types, 
  1. IAAS ( Infrastructure As Service)
  2. PASS( Platform As Service)
  3. SAAS (Software As Service)
The below diagram explains all three types of cloud - IAAS, PAAS, and SAAS.

IAAS (Infrastructure As Service)

Infrastructure as a service is also known as Hardware as a Service (HAAS).
An infrastructure is a basic form of service. Let’s assume that you have rented a shop, so the owner gives you basic Infrastructure like electricity and the rest of the things you have to make your own as per your requirements to run the shop. Similarly IAAS provides computing Architecture & Infrastructure. It provides Data Storage, Virtualization, Servers, and Networking.
Most of the companies have Infrastructure teams which use this service; eg., System administrator.
The below diagram shows on-premise and cloud responsibility for IAAS,
Advantages of IAAS 
  1. Reduce Risk.
  2. Deployment Speed.
  3. Geographical Advantages.
  4. Unlimited Scalability.

PAAS (Platform As Service)

Platform as a service manages Runtime, Middleware, and OS services. We can say, It is a layer created top of the IAAS services (Virtualization, Servers, Storage, and Networking).
PAAS = IAAS Services (Virtualization, Servers, Storage and Networking) + PAAS Services (Runtime, Middleware, and OS services)

Software developer uses Platform As a Service.
Suppose you have two applications and need a development environment for them, the application is using the below technologies and web servers.
  1. .Net Core and SQL
  2. Java and Oracle
  3. IIS and Apache
Cloud service provider installs all required frameworks and makes your development environment ready in a few clicks.
The below diagram shows on-premise and cloud responsibility for PAAS,
  1. Reduce development time
  2. Support global teams
  3. Develop cross-platform application
  4. Affordability

Azure as SAAS (Software as Service)

Software as a service is also known as Software delivered over the web. The below diagram is self-explanatory.
The cloud service provider will handle everything for you. The end-user should only have high-speed internet and the rest will be taken care of by the cloud service provider.
Many applications like Dropbox, Salesforce, Cisco Webex, and GoTo Meeting can be used through the internet.
SAAS = IAAS Services (Virtualization, Servers, Storage and Networking) + PAAS Services (Runtime, Middleware, and OS services) +SAAS (Applications + Data) 
Suppose you have two applications which have
  1. .Net & SQL
  2. Jave & SQL
The Cloud provider will take care of everything, all software, Framework, and servers together for these applications. That's SAAS.
  1. Maintenance, security, and licences are taken care of by the cloud providers.
  2. Cost-effective
  3. Fast development 
  4. Access from anywhere
In short, the below diagram explains all the cloud service models (on premises, IAAS, PAAS, SAAS). You can see the responsibility to manage by you and the cloud provider.
I hope you enjoyed this article. Thanks for your time.

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