Infrastructure as a Service (IaaS) is a cloud computing distribution model in which the provider hosts the infrastructure (servers, CPU, GPU, RAM, storage, network) and manages it. It is one of the four types of cloud services, along with software as a service (SaaS), platform as a service (PaaS), and serverless computing. IaaS usually comes in two main forms: managed or unmanaged. Organizations choose IaaS because it's often easier, faster, and more cost-effective to operate a workload without having to purchase, manage, and support the underlying infrastructure.
IaaS customers access resources and services over a wide area network (WAN), such as the Internet, and can use cloud provider services to install the remaining elements of an application stack. The Platform as a Service (PaaS) model adds a managed services layer to IaaS resources. It can support up to petabytes of data, automatically scaling as files are added and removed, eliminating the need to configure and manage storage capacity. PaaS is designed to make it easy for developers to quickly create web or mobile applications, without worrying about configuring or managing the underlying server, storage, network and database infrastructure needed for development.
The Software-as-a-Service (SaaS) model provides fully managed software that is delivered directly to end users. The main benefit of SaaS is that it offloads all infrastructure and application management to the SaaS provider. However, just because all of your IT resources are hosted by a cloud service provider doesn't mean that the provider helps you with the managed service issues mentioned above. Azure managed disks are block-level storage volumes managed by Azure and used by Azure virtual machines.
In addition, an organization must thoroughly evaluate the capabilities of its IT department to determine how well equipped it is to cope with the current demands of implementing IaaS. IaaS eliminates the cost of configuring and managing a physical data center, making it a cost-effective option for migrating to the cloud.