In the context of virtualization, Host OS and Guest OS refer to the operating systems running on the physical server and the virtual machines, respectively.
Host OS: The Host OS is the operating system that runs directly on the physical server, and it provides the foundation for virtualization. The Host OS manages the physical hardware resources, such as CPU, memory, and storage, and it also runs the VMM (Virtual Machine Monitor), also known as Hypervisor. The Host OS is responsible for creating, managing, and monitoring the virtual machines and their associated resources.
Guest OS: The Guest OS is the operating system running within a virtual machine, and it is installed on a virtual hard disk that is emulated by the VMM. Each virtual machine can run a different Guest OS, which can be the same or different from the Host OS. The Guest OS sees a virtualized hardware environment provided by the VMM, which includes virtual CPUs, memory, storage, and network interfaces. The Guest OS operates as if it were running on physical hardware, and it runs applications and services just like any other operating system.
The Host OS and Guest OS interact with each other through the VMM, which provides the necessary interfaces and services for the virtual machines to access the physical hardware resources. The VMM isolates each virtual machine from the others, and it also provides the ability to migrate virtual machines between physical servers without any downtime.
In summary, the Host OS runs directly on the physical server and provides the foundation for virtualization, while the Guest OS runs within a virtual machine and interacts with the physical hardware through the VMM.
