A virtual machine is a set of virtual hardware whose characteristics are determined by a set of encapsulated files; it is this virtual hardware that a guest operating system is installed on. A virtual machine runs an operating system and a set of applications in a similar fashion to a physical server. Essentially, a virtual machine is comprised of configuration files and its physical resources are provided by an ESXi host.
Virtual machines are created within a virtualization layer, and this virtualization layer manages requests from the virtual machine for resources such as CPU or memory. It is this virtualization layer that is responsible for translating these requests to the underlying physical hardware.
Each virtual machine is granted a portion of the physical hardware. All VMs have their own virtual hardware (there are important ones to note, called the core 4: CPU, memory, disk, and network). Each VM is isolated from the other and each...