Cloud Computing Categories

1. Infrastructure as a service (IaaS)

Infrastructure as a Service is the most flexible category of cloud services. It aims to give you complete control over the hardware that runs your application (IT infrastructure servers and virtual machines (VMs), storage, networks, and operating systems). Instead of buying hardware, with IaaS, we rent it. It’s an instant computing infrastructure, provisioned and managed over the internet.

IaaS, ensures that a service is up and running is a shared responsibility: the cloud provider is responsible for ensuring the cloud infrastructure is functioning correctly; the cloud customer is responsible for ensuring the service they are using is configured correctly, is up to date, and is available to their customers. This is referred to as the shared responsibility model.

IaaS – Commonly used Scenarios

  • Migrating workloads – IaaS facilities are managed in a similar way as on-premises infrastructure and provide an easy migration path for moving existing applications to the cloud.
  • Test and development – Teams can quickly set up and dismantle test and development environments, bringing new applications to market faster. IaaS makes scaling development and testing environments, fast and economical.
  • Storage, backup, and recovery – Organizations avoid the capital outlay and complexity of storage management, which typically requires skilled staff to manage data and meet legal and compliance requirements. IaaS is useful for managing unpredictable demand and steadily growing storage needs. It simplifies the planning and management of backup and recovery systems.

2. Platform as a service (PaaS)

PaaS provides an environment for building, testing, and deploying software applications. The goal of PaaS is to help you create an application quickly without managing the underlying infrastructure. PaaS is a complete development and deployment environment in the cloud, with resources that enable organizations to deliver everything from simple cloud-based apps to sophisticated cloud-enabled enterprise applications. Such that the resources are purchased from a cloud service provider on a pay-as-you-go basis and accessed over a secure Internet connection.

PaaS – Commonly used Scenarios

  • Development framework – PaaS provides a framework that developers can build upon to develop or customize cloud-based applications. PaaS lets developers create applications using built-in software components.
  • Analytics or business intelligence – Tools provided as a service with PaaS allow organizations to analyze and mine their data for insights and patterns, and predict outcomes to improve business decisions such as forecasting, product design, and investment returns.

3. Software as a service (SaaS)

SaaS is software that is centrally hosted and managed for the end customer. It is usually based on an architecture where one version of the application is used for all customers, and licensed through a monthly or annual subscription. E.g. Office 365, Skype, and Dynamics CRM Online.

Cost and Ownership

  IaaS PaaS SaaS
Upfront Costs There are no upfront costs. Users pay only for what they consume. There are no upfront costs. Users pay only for what they consume. Users have no upfront costs. They pay a subscription typically on a monthly or annual basis.
User Ownership The user is responsible for the purchase installation, configuration, and management of their own software, operating systems, middleware and applications. The user is responsible for the development of their own application. However, they are not responsible for managing the server or infrastructure. This allows the user to focus on the application or workload they want to run. Users just use the application software, they are not responsible for any maintenance management of that software.
Cloud Provider Ownership The cloud provider is responsible for ensuring that the underlying cloud infrastructure (such as virtual machines, storage and networking) is available for the user. The cloud provider is responsible for operating system management, network, and service configuration. Cloud providers are typically responsible for everything apart from the application that a user wants to run. They provide a complete managed platform on which to run the application The cloud provider is responsible for the provision management, and maintenance of the application software.

Management Responsibilities

These categories are layers on top of each other. Just like, PaaS adds a layer on top of IaaS by providing a level of abstraction. The abstraction has the benefit of hiding the details that you may not care about, so that you can get to coding quicker. However, one aspect of the abstraction is that you have less control over the underlying hardware.

The below example shows a list of resources that you manage and that your service provider manages in each cloud service category.

IaaS, PaaS, and SaaS each contain different levels of managed services. You may easily use a combination of these types of infrastructure. With the cloud’s flexibility, you can use any combination that provides you with the maximum result.

For more on Tutorial visit – Microsoft Azure Fundamental (AZ-900)