IaaS, PaaS, SaaS, FaaS

• Infrastructure as a Service(IaaS): is where you have a hypervisor (i.e., a program used to run and manage one or more virtual machines on a computer) or it can also be used to rent the physical server itself. In simple words, it allows hosting an operating system on the cloud which would be unique to the user. Nobody else would log into it and it can be managed by the user. With the IaaS you only pay for what you use, and the payment depends on the model being used.
  For Example, in Amazon, it is a per-second billing model right now for the Linux instances and per hour for the Windows instances. In Google, the cost is on a per-minute basis. In the IaaS model, there is no long-term or fixed contract. If the service needs to be stopped it can be powered down and then the user would not incur any charge.
• Platform as a Service(PaaS): is where we don’t necessarily know what resources are needed but the code is present, and PaaS is used to go in and provision the resources for you. It is something like Elastic Beanstalk (AWS Elastic Beanstalkis an easy-to-use service for deploying and scaling web applications and services) So Elastic Beanstalk will provision you with elastic load balances, with EC2 instances, with databases, etc.
  So, in the Platform as a Service market, Azure was really strong but Elastic Beanstalk came out with Amazon. In short in Paas, we must look after the underlying assets but don’t necessarily have to worry about the provisioning of it.
• Software as a Service(SaaS): is the easiest to understand. Think of any email provider. Example Outlook. With Outlook all you worry about is the actual software, like your inbox, spam filters, if it is functioning according to your needs. You are not worried about the underlying servers, that is not your problem.
  Neither do you worry about how the load balance works or about how they provide high availability or how they do their DNS reading. Software as a Service is where the focus lies on the actual software itself.
• Functions as a Service(Faas):is when we utilize functions that are written by somebody else. The functions can be used to break down applications from these monolithic applications into something that is a lot smaller and decoupled.
  For example, if there is a function to make a payment, then the code for it can be used and recycled to suit your own application. It is identity authorization (Authentication confirms that users are who they say they are)

-Sanjana