In virtualisation, a hypervisor is used to create and run virtual machines.
This means that multiple operating systems can share a single hardware host, with the hypervisor controlling how resources are allocated on the processor to each virtual machine.
The hypervisor exists outside of a guest operating system and intercepts the commands sent to the computer hardware.
It can then manage the traffic of the different virtual machines, comparing the requirements with what is available to be used in terms of processing power.