Virtual Machines

Question 1

A virtual machines abstracts a ______ computer into several different _________ environments

Answer 1

single, execution

Question 2

Every execution environment thinks it runs on its own __________

Answer 2

computer

Question 3

A virtual machine manager (VMM) is also called a __________

Answer 3

Hypervisor

Question 4

What does a VMM do?

Answer 4

Create and run virtual machines which run guest OSs

Question 5

There and VMM that are run by ______ and ______

Answer 5

hardware, software

Question 6

Where does the VMM lie between the layers of Process, kernel, and hardware?

Answer 6

Between kernel and hardware

Question 7

Review the virtual machine structure

Answer 7

Review the virtual machine structure

Question 8

A VM offers ________ and ________ between host and guest OSs

Answer 8

protection, isolation

Question 9

A VM can host different kinds of ___________ ______

Answer 9

operating systems

Question 10

A VM can suspend, ______, clone, _______, migrate, and do _____ computing

Answer 10

resume, backup, cloud

Question 11

When a guest attempts to execute a privileged instruction, a _____ is raised to the VMM in the real machine, the VMM ______ the action for guest, and there is a ________ since it is not run on hardware

Answer 11

trap, executes, slowdown

Question 12

If CPU commands behave different based on privilege, the _____ and _________ cannot be used

Answer 12

trap, emulate

Question 13

Trap and emulate is a method to handle ________ instructions

Answer 13

privileged

Question 14

When a guest OS is in user mode, run commands on the _______ ____

Answer 14

physical CPU

Question 15

When a guest OS is in kernel mode, what are 2 outcomes when an instruction is run?

Answer 15

• Not Special Instruction: run natively

- Special Instruction: translate into a new set of instructions and execute via the VMM

Question 16

The VMM maps guest page tables to _______ _____ _____

Answer 16

nested page tables (NPT)

Question 17

Each guest OS pagin operation is translated to a _______ _____ _____ operation

Answer 17

nested page table

Question 18

What are the 2 modes of operations for hardware acceleration?

Answer 18

host and guest

Question 19

vCPU data structures load and store _____ CPU states quickly

Answer 19

guest

Question 20

Guest memory is managed by _______ nested page tables

Answer 20

hardware

Question 21

The hardware translates addresses for guest OS _____ operations

Answer 21

DMA

Question 22

The VMM has to route ________ to the correct guest OSs

Answer 22

interrupts

Question 23

What are 6 types of Hypervisors?

Answer 23

• Type 0
• Type 1
• Type 2
• Programming Environment Virtualization
• Emulation
• Containers

Question 24

In ______ Hypervisors, the hardware has a feature where it is partitioned and dedicated for different guest OSs.

Answer 24

Type 0

Question 25

In ______ Hypervisors, guests can host other _____

Answer 25

guests

Question 26

In Type 1 Hypervisors, _______ OSs that manage other guest OSs run on hardware. Type 1s provide an ________ ____ for backup, monitoring, etc

Answer 26

custom, interface API

Question 27

_______ Hypervisors are typical in data centers for consolidation

Answer 27

Type 1

Question 28

_______ Hypervisors are application level virtual machine managers

Answer 28

Type 2

Question 29

What is an example of a Programming Environment Virtualization?

Answer 29

Java Virtual Machine

Question 30

_____ programs run within the JVM

Answer 30

Java

Question 31

What is emulation?

Answer 31

Allows guest systems compiled for a different architecture compared to that of the host system

Question 32

Emulation translates source system ________ to equivalent instructions on the target system

Answer 32

instructions

Question 33

________ don't provide complete virtualization for applications that require the same OS but dont need complete virtualization

Answer 33

Containers

Question 34

What are 5 core functionalities all Hypervisors have to manage?

Answer 34

* CPU Scheduling * Memory Management * I/O Management * Storage Management * Live Migration

Question 35

VMMs map ______ to physical CPUs

Answer 35

vCPUs

Question 36

Due to ________, time-of-day clocks in vCPUs are _______

Answer 36

scheduling, incorrect

Question 37

Some VMMs include applications to correct ______ ______

Answer 37

clock drifts

Question 38

Memory pressure is ____ when running VMs

Answer 38

high

Question 39

VMs has double ________, which degrades performance

Answer 39

paging

Question 40

VMMs detect the same pages loaded multiple times and keep them ____

Answer 40

once

Question 41

____ is easy to manage in VMMs since drivers are loadable modules

Answer 41

I/O

Question 42

VMMs provide direct I/O control to improve I/O __________

Answer 42

performance

Question 43

In VMMs, the disk image is maintained is a _____ ____, making it easy for cloning, backup, and migration

Answer 43

single file

Question 44

VMM storage management requires physical to virtual conversion of ____ _______

Answer 44

disk blocks

Question 45

VMMs store multiple file systems as separate _______

Answer 45

images

Question 46

Live migration is available only for ______ and ______ hypervisors

Answer 46

Type 0, Type 1

Question 47

Live migration allows seamless _____ ________, server maintenance, etc

Answer 47

load balancing

Question 48

Describe the general process of a live migration

Answer 48

1. Create Guest Target 2. Send all pages to Target 3. Terminate Guest Source