Demystifying the Hypervisor: Unveiling its Role and Ensuring Resource Isolation in Virtualized Environments

A hypervisor, also known as a virtual machine monitor (VMM), serves an essential role in a virtualized environment. Its primary function is to create and manage virtual machines (VMs) - these are the environments where the guest operating systems run. In regard to system resources, the hypervisor works as a regulating force, responsible for allocating resources such as compute (CPU), memory, storage, and network access to guest operating systems. The goal here is optimal utilization of the underlying physical hardware and ensuring that each VM receives the resources it requires to function effectively. To ensure exclusive access to system resources for each guest operating system, the hypervisor uses a strategy called partitioning. In essence, it divides the system's physical resources and allocates them to different guest operating systems, effectively isolating these machines from one another. This means that each of these VMs works on its own set of resources, and it's prevented from impacting the performance or security of other VMs on the same physical host. Further, there are two types of hypervisors: 1. Type 1 Hypervisor, also known as bare-metal hypervisor: This kind of hypervisor runs directly on the host's hardware, controlling it and managing guest operating systems. Examples include Microsoft Hyper-V, VMware ESXi, and Citrix XenServer. 2. Type 2 Hypervisor, also known as hosted hypervisor: These hypervisors run on a conventional operating system just as other computer programs do. But they can still host guest operating systems within them. Examples include Oracle VirtualBox and VMware Workstation. In both these types, the hypervisor ensures fair and efficient allocation, isolation, and governance of the system's resources among guest OSs.