Virtualization Technologies Questions and Answers

Answer: B

The diagram shows a Type 2 Hypervisor or virtual machine monitor.

In the stack, the hypervisor sits on top of an operating system that runs on the hardware, and a guest operating system with its application runs on top of the hypervisor. A hypervisor that runs as a program on a host operating system is a Type 2 (hosted) hypervisor, as with VirtualBox or VMware Workstation.

A Type 1 (bare-metal) hypervisor would sit directly on the hardware with no host operating system below it. There are no standard Type 3 or Type 4 hypervisors.

Answer: D

Templates are implemented using the COW (copy on write) format.

In virtual cluster management (as described by Hwang, Fox and Dongarra), a template virtual machine image is shared, and new virtual machines are created from it using copy-on-write disks: each VM writes its changes to its own small layer while reading unchanged blocks from the template, which makes deployment fast and saves storage.

'Skip and relay' and 'copy and relay' are not image formats, and NOW (network of workstations) is a kind of cluster, not a way of implementing templates.

Answer: A

The true statement is that privileged and sensitive calls are automatically trapped to the hypervisor.

The original x86 architecture had sensitive instructions that did not trap when run in user mode, which made classic trap-and-emulate virtualization impossible. Hardware-assisted virtualization (Intel VT-x, AMD-V) adds a new CPU mode for the hypervisor, so that privileged and sensitive instructions executed by a guest automatically trap to it.

Binary translation is the software technique used for full virtualization before such hardware support, and paravirtualization modifies the guest operating system to make hypercalls instead. The Application Binary Interface is not the trapping mechanism.

Answer: B

A type-I hypervisor runs directly on top of the hardware with the ISA exposed by the hardware.

A type-1 (bare-metal) hypervisor, such as Xen, VMware ESXi or Hyper-V, is installed directly on the physical machine. It presents each guest operating system with the hardware's instruction set architecture (ISA), so guests run as if on real hardware.

Interacting with a host OS through the ABI describes a process virtual machine, and 'hosted virtual machine' is the type-2 hypervisor, which runs on top of a host operating system. Guests of a type-1 hypervisor see an ISA, not an API.

Answer: A

A snapshot is a backup of the virtual machine's current state.

A hypervisor snapshot captures the whole state of a VM at a point in time: its virtual disks, memory and device configuration. The VM can later be reverted to that point, which is useful before updates or tests.

The snapshot covers the VM as a whole, not just the guest operating system or its applications, and the host operating system is outside the VM altogether.