Virtualization Concepts and Cloud Computing

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Questions and Answers

What is a characteristic of second-generation virtualization?

Enables substantial memory sharing between VMs (correct)

Is fully hardware-based without software components

Requires no awareness from the operating system

Is dependent on third-party virtualization solutions

Which of the following must the OS vendor provide for paravirtualization to function effectively?

A paravirtualization-enabled version (correct)

An unmodified version of the operating system

A complete hardware solution

A separate hypervisor

What is a primary disadvantage of paravirtualization?

Requires the use of virtualization software

Eliminates the need for inter-VM communications

High performance without OS modifications

Necessitates a modified guest operating system (correct)

In the context of virtualization, what do Microsoft Windows enlightenments refer to?

Partial paravirtualization through drivers Signup and view all the answers

What is one benefit of OS awareness of virtualization in second-generation systems?

Enhanced collaboration for VM management Signup and view all the answers

What is the primary benefit of virtualization in cloud computing?

Decoupled management of virtual servers from physical machines Signup and view all the answers

Which of the following describes the concept of paravirtualization?

Modification of the guest operating system to communicate directly with the hypervisor Signup and view all the answers

Which characteristic is NOT associated with IaaS platforms in cloud computing?

Providing dedicated physical servers only Signup and view all the answers

What impact does hardware support have on virtualization?

It enhances isolation between virtual machines Signup and view all the answers

Which advantage does virtualization provide specifically for cloud computing?

Ability to efficiently utilize a large set of virtual servers Signup and view all the answers

What is a primary characteristic of hypervisor-based rootkits?

They can achieve higher privilege levels than the kernel. Signup and view all the answers

Which of the following is a type of attack that exploits hypervisor security vulnerabilities?

Collocation attacks Signup and view all the answers

In desktop virtualization, which statement accurately describes the requirements?

The guest OS is run inside the user host OS. Signup and view all the answers

Which disk image format is commonly used for read/write operations?

.VHD Signup and view all the answers

What is the primary use of the Open Virtual Machine format (OVF/OVA)?

To define VM metadata and configurations. Signup and view all the answers

What is a limitation of most Virtual Machine Monitors (VMM) regarding VM operations?

Suspended VMs are generally not portable across different VMMs. Signup and view all the answers

Which type of virtualization software allows running multiple guest operating systems on a host OS?

Hypervisor Signup and view all the answers

Which virtualization software is considered commercial for desktop environments?

VMWare Fusion Signup and view all the answers

What is the range of hourly pricing for Amazon EC2 servers?

$0.113 to $6.82 Signup and view all the answers

What is the cost for data storage in Google Compute Engine?

$0.04 / GB / month Signup and view all the answers

Which service does not charge for incoming data?

Google Compute Engine Signup and view all the answers

What is the cost for outgoing data beyond the first 1 GB in Amazon EC2?

$0.09 down to $0.05 / GB Signup and view all the answers

What is the maximum cost for a virtual machine per hour in Rackspace open Cloud?

$5.44 Signup and view all the answers

What is the lowest storage cost for Google Compute Engine's backup option?

$0.125 / GB / month Signup and view all the answers

How much does Windows Azure charge for outgoing data after the first 5 GB?

$0.18 to $0.05 / GB Signup and view all the answers

What is the monthly storage cost range for files in Rackspace open Cloud?

$0.1 to $0.12 / GB Signup and view all the answers

What is the main function of the emulation layer in first-generation virtualization?

It translates instructions for the CPU and other hardware. Signup and view all the answers

Which statement accurately describes the guest operating system in first-generation virtualization?

It runs unaware that it is in an emulated environment. Signup and view all the answers

What is the primary method used in first-generation virtualization for translating CPU instructions?

Binary rewriting. Signup and view all the answers

What is an example of a tool used for first-generation virtualization by binary rewriting?

QEMU Signup and view all the answers

In the context of first-generation virtualization, what is the term 'full virtualization' referring to?

Complete emulation of all hardware as virtual devices. Signup and view all the answers

What is the primary purpose of OS-level virtualization?

To arbitrate between competing resource demands Signup and view all the answers

Which component is necessary for the efficient implementation of virtual memory?

Memory Management Unit (MMU) Signup and view all the answers

In the context of virtual CPUs, what process is necessary to manage thread execution?

Context save/restore mechanism Signup and view all the answers

What does each process in a virtual memory system believe regarding its address space?

It has its own isolated address space Signup and view all the answers

What does platform virtualization enable on a physical computer?

Multiple virtual computers to operate simultaneously Signup and view all the answers

Which of the following is NOT a benefit of hardware support in virtualization?

Direct memory access for all applications Signup and view all the answers

How does OS-level virtualization manage competing demands for I/O and memory resources?

Through policies established by the OS Signup and view all the answers

In a virtualized system, what does the virtualization layer do?

Allows multiple OS to run on a single physical machine Signup and view all the answers

Study Notes

Course Objectives

Understand machine virtualization and its relevance to cloud computing
Explore paravirtualization, hardware support, and their impact on performance and security
Describe features and services offered by IaaS platforms in public and private clouds
Connect IaaS services to the functions and roles of a traditional operating system

Introduction

Virtualization abstracts resources from physical resources presented to users and applications.
Cloud computing enables decoupled management of virtual cloud servers (IaaS, PaaS, SaaS) and the physical machines supporting them.
Key advantages include cost-efficiency, flexibility (unified OS/app management), isolation, dependability, and performance improvements.

Outline

Basics of OS-level virtualization
Principles of platform virtualization
Requirements for cloud computing
Virtualization implementation (OS support, hardware support, performance, and portability)
Desktop virtualization

Basics: OS-Level Virtualization

A single operating system (OS) supports multiple processes and applications.
Processes cannot freely access system resources.
Virtualization is needed to manage resource allocation among processes.
OS implements policies for resource arbitration.

Example 1: Virtual Memory

Each process has its own address space, isolating it from others.
The OS maps virtual addresses to physical addresses(memory).
Built-in hardware support (e.g., MMU, TLB) is essential for efficient implementation.

Example 2: Virtual CPU

Each thread assumes it handles CPU operations.
Context switching is crucial to manage and schedule threads.
Hardware support (e.g., process-aware TLB) enhances virtual CPU functionality.

Platform Virtualization

A single physical computer can support multiple virtual computers sharing resources between multiple operating systems and applications.

A Key Enabling Technology for Cloud Computing

Virtualized servers outnumber non-virtualized ones (2014 data).
Advantages for users include resource abstraction, isolation, pay-as-you-go deployments, and instance migration.
Advantages for cloud operators include reduced operational costs, larger efficient server capabilities, and increased operational flexibility (migration, consolidation, etc.).
Disadvantages may include costs associated with multiple OS versions, and performance penalties.

Virtualization Implementation

Modern OS isolation depends on multiple instruction modes.
Non-privileged instructions, like mathematical operations, typically operate without interruption,.
Privileged instructions require kernel-level access, typically for critical operations like process termination

Virtualization Requirements

CPU instructions are classified as privileged or sensitive instructions, affecting virtual machine management.
Required properties include equivalence (same output as raw hardware), resource control, and efficiency.
Effective virtual machine management (VMM) construction can be achieved when sensitive instructions are a subset of privileged instructions,.

x86 and Virtualization

Initially (around 2010 when cloud computing gained interest), x86 architecture for desktops and servers and used 32 bits.
Commercial interest in virtualization was significant.
However, original x86 32 bits architecture was not designed with virtualization in mind .
More complex x86-32 architectures include a large number of sensitive instructions.
Modern processors directly support virtualization with hardware-assisted virtualization.

Server Virtualization Approaches

Three generations of server virtualization exist
First generation: Binary Rewriting (software-based full virtualization).
Second generation: Paravirtualization (software-based collaborative virtualization).
Third generation: Hardware-assisted full virtualization (hybrid approach combining software and hardware).

First Generation Virtualization

An emulation layer exists in the host operational system, enabling the emulation of all hardware components including the CPU.
Binary rewriting translates instructions on the fly.
The guest OS is unaware it is running on an emulated environment .
Tools, like QEMU, support this type of virtualization.

First Generation Virtualization (Advantages and Disadvantages)

Significant advantages include good VM isolation, precise VM resource control, and total transferability.
However, significant disadvantages are significant performance penalties.
VMs cannot use hardware instructions directly and require emulation.

Second Generation Virtualization (Paravirtualization)

The guest OS is modified so it does not need to use privileged instructions itself.
It correctly interfaces with the hypervisor to handle privileged operations.
Paravirtualization dramatically improves performance.

Second Generation Virtualization (Advantages & Disadvantages)

Optimized performance.
Requires modified OS, which is a limitation.

Third Generation Virtualization

Hardware support exists for virtualization.
Guests can use privileged instructions without intervention from the hypervisor, resulting in high performance.
However, it is important for OS to recognize virtualization.

Some Common Virtualization Solutions

VirtualBox (full and hybrid virtualization with hardware support)
KVM (full and hybrid virtualization with hardware support, utilizing virtio for I/O device drivers)
VMware (full range of virtualization types).

Virtualization and Security

Hypervisor-based rootkits can exploit vulnerabilities in a non-virtual system and exploit hardware-assisted virtualization.
Collocation attacks leverage security flaws in the hypervisor

Desktop Virtualization

Run a guest operating system within the host operating system.
Less stringent performance requirements.
Often use paravirtualization to efficiently share resources like network cards and other devices.

VM Images and Operations

Disk images (read/write and read-only) are used for VMs.
Common formats include VHD, VDI, QCOW2, and ISO.
VM imports/exports use OVF, OVA, and AMI formats..
VMs can be migrated between environments.

Part II - IaaS Management

IaaS is a model for renting cloud infrastructure resources.
IaaS allows users to manage their own operating systems and environments.

Key Players in the Public Cloud IaaS Market

Amazon Web Services
Microsoft Azure
HP
Google Compute Engine
Rackspace Open Cloud
IBM SmartCloud

Public Cloud IaaS Operations

Dynamically allocate resources like VMs.
Deploying a VM image to a host from an image.
Migrate a VM between hosts, modifying required resource amounts dynamically.
Manage access keys (e.g., SSH).

Defining Needs: Instances

Users configure VMs' computational capacity (VCPU, memory) and storage types (remote or dedicated).
Example configuration from Rackspace includes General purpose, Compute optimized, I/O optimized, and Memory optimized.

Typical laaS Pricing

Pricing varies by provider and instance type.
Factors like storage, network bandwidth, operating system type, and location can affect pricing.

Spot Instances Mechanics

Best-effort instances with low cost.
Used by IaaS providers to maximize infrastructure utilization and offer competitive pricing on unused machines.
Pricing is based on a bidding/offering mechanism.
The market adapts to the current demand

Example of Use

Resizing photos and complex tasks like video encoding are typically more expensive if used on general and regular VMs due to ongoing use of infrastructure.
Utilization of a cloud environment is beneficial when these type of applications require significant computation capacity.

Bitmovin Example

Re-encoding HD video requires high processing power.
Utilizing spot instances reduces costs.

laaS Management: The "Cloud Operating Systems"

Cloud operating systems manage the fleet of hosts, virtual machines, and resources.
Operations such as allocation, monitoring (usage, faults), and billing are performed by a IaaS management system.

An Operating System Analogy

laaS management platforms are analogous to operating systems, managing resources and handling VM(s) instead of processes and applications, and managing inter-VM networking.

Direct Infrastructure Access

Direct infrastructure access allows users to access and interact with infrastructure without mediation via hypervisor.

laaS Management Platform

laaS platforms manage the host(s), monitor resources, allocate resources to VMs.
A command line or web interface is typically used for management.

Advantages of Using an laaS Management System

Unified management and control is possible allowing centralized management/control of numerous servers.
Better resource allocation due to centralized control and monitoring allowing better utilization.
Improved security due to enhanced authentication, and access control. Increased reusability if VM images are stored and deployable by multiple users across environments.

OpenStack

Large open-source project.
Driven by Rackspace and a large community of companies offering cloud-based solutions.
Meeting the requirements of large scale public and private clouds with high scalability.

Conclusion

Virtualization is crucial for economies of scale and efficiency in cloud computing, enabling easy management, allocation, and monitoring of IaaS resources.
Public cloud IaaS offers on-demand renting of infrastructure (VMs, networks, and storage).
Private and hybrid clouds similarly make use of operating systems software on physical hosts or on VMs, allowing management, authentication, and monitoring functionalities.

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Description

Test your knowledge on the key concepts of virtualization and its impact on cloud computing. This quiz covers paravirtualization, hypervisor security, and the role of operating systems in virtualization. Enhance your understanding of how virtualization benefits cloud infrastructures.