Virtual Machines Flashcards
A virtual machines abstracts a ______ computer into several different _________ environments
single, execution
Every execution environment thinks it runs on its own __________
computer
A virtual machine manager (VMM) is also called a __________
Hypervisor
What does a VMM do?
Create and run virtual machines which run guest OSs
There and VMM that are run by ______ and ______
hardware, software
Where does the VMM lie between the layers of Process, kernel, and hardware?
Between kernel and hardware
Review the virtual machine structure
Review the virtual machine structure
A VM offers ________ and ________ between host and guest OSs
protection, isolation
A VM can host different kinds of ___________ ______
operating systems
A VM can suspend, ______, clone, _______, migrate, and do _____ computing
resume, backup, cloud
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
trap, executes, slowdown
If CPU commands behave different based on privilege, the _____ and _________ cannot be used
trap, emulate
Trap and emulate is a method to handle ________ instructions
privileged
When a guest OS is in user mode, run commands on the _______ ____
physical CPU
When a guest OS is in kernel mode, what are 2 outcomes when an instruction is run?
- Not Special Instruction: run natively
- Special Instruction: translate into a new set of instructions and execute via the VMM
The VMM maps guest page tables to _______ _____ _____
nested page tables (NPT)
Each guest OS pagin operation is translated to a _______ _____ _____ operation
nested page table
What are the 2 modes of operations for hardware acceleration?
host and guest
vCPU data structures load and store _____ CPU states quickly
guest
Guest memory is managed by _______ nested page tables
hardware
The hardware translates addresses for guest OS _____ operations
DMA
The VMM has to route ________ to the correct guest OSs
interrupts
What are 6 types of Hypervisors?
- Type 0
- Type 1
- Type 2
- Programming Environment Virtualization
- Emulation
- Containers
In ______ Hypervisors, the hardware has a feature where it is partitioned and dedicated for different guest OSs.
Type 0
In ______ Hypervisors, guests can host other _____
guests
In Type 1 Hypervisors, _______ OSs that manage other guest OSs run on hardware. Type 1s provide an ________ ____ for backup, monitoring, etc
custom, interface API
_______ Hypervisors are typical in data centers for consolidation
Type 1
_______ Hypervisors are application level virtual machine managers
Type 2
What is an example of a Programming Environment Virtualization?
Java Virtual Machine
_____ programs run within the JVM
Java
What is emulation?
Allows guest systems compiled for a different architecture compared to that of the host system
Emulation translates source system ________ to equivalent instructions on the target system
instructions
________ don’t provide complete virtualization for applications that require the same OS but dont need complete virtualization
Containers
What are 5 core functionalities all Hypervisors have to manage?
- CPU Scheduling
- Memory Management
- I/O Management
- Storage Management
- Live Migration
VMMs map ______ to physical CPUs
vCPUs
Due to ________, time-of-day clocks in vCPUs are _______
scheduling, incorrect
Some VMMs include applications to correct ______ ______
clock drifts
Memory pressure is ____ when running VMs
high
VMs has double ________, which degrades performance
paging
VMMs detect the same pages loaded multiple times and keep them ____
once
____ is easy to manage in VMMs since drivers are loadable modules
I/O
VMMs provide direct I/O control to improve I/O __________
performance
In VMMs, the disk image is maintained is a _____ ____, making it easy for cloning, backup, and migration
single file
VMM storage management requires physical to virtual conversion of ____ _______
disk blocks
VMMs store multiple file systems as separate _______
images
Live migration is available only for ______ and ______ hypervisors
Type 0, Type 1
Live migration allows seamless _____ ________, server maintenance, etc
load balancing
Describe the general process of a live migration
- Create Guest Target
- Send all pages to Target
- Terminate Guest Source