CloudComputingArchitecture Module 1 ppt.pptx

www.cambridge.edu.in
Department of Information Science &
Engineering
CLOUD COMPUTING AND APPLICATIONS

Department of Information Science & Engineering

Mastering Cloud Computing

Chapters
Module I:
Chapter 1 — Introduction
Module II
Chapter 3 — Virtualization
Module III
Chapter 4 — Cloud Computing Architecture
Module IV ---- Textbook 2 Chapter 9 ---- Cloud Security
Module V
Chapter 9 (9.1 and 9.2) — Cloud Platforms in Industry &
Chapter 10 — Cloud Applications

The Next Revolution in IT The
Big Switch in IT
• Classical Computing
– Buy & Own
• Hardware, System Software,
Applications often to meet peak
needs.
– Install, Configure, Test, Verify
– Manage
• – ..
– Finally, use it
• – $$$$....$(High CapEx)
• Cloud Computing
– Subscribe
– Use
– $ - pay for what you use,
– based on QoS
Every
18
months?

Cloud Computing Definition
• Cloud computing is a technological advancement it is based on
the concept of dynamic provisioning,
• The services ,compute capability, storage, networking, and
information technology (IT) infrastructure.
• Resources are made available through the Internet and offered
on a pay-per-use basis from cloud computing vendors.

Vision of Cloud Computing

I need to grow my
infrastructure, but I do
not know for how long…
I cannot invest in
infrastructure, I just
started my business….
I want to focus on
application logic and not
maintenance and scalability
issues
I want to access and edit
my documents and photos
from everywhere..
I have a surplus of
infrastructure that I want
to make use of
I have a lot of
infrastructure that I want
to rent …
I have infrastructure and
middleware and I can host
applications
I have infrastructure and
provide application
services

Compute
Storage
Applications
Development and
Runtime Platform
Cloud Manager
Private Resources
Private Cloud Private Cloud (Government)
Public Clouds
Government Agencies
Organization Personnel
All users, on any device

Defining Cloud
Cloud computing is a model for enabling
ubiquitous, convenient, on-demand network
access to a shared pool of configurable
computing resources (e.g., networks,
servers, storage, applications, and services)
that can be rapidly provisioned and released
with minimal management effort or service
provider interaction.

IT outsourcing
Security
No capital investments
Quality of
Service
Pay as you go
Billing
Cloud
Computing?

A Closer look
• Cloud computing Helping
• Enterprises
• Governments
• Public Institutes
• Private Institutes
• Research Organization

Examples
• Large enterprise can offload some of their activities to Cloud based system.

Example
• Small Enterprises and Start-ups can afford to translate into business results their
ideas more quickly without excessive upfront cost

Example
• System Developers can concentrate on business logic rather than dealing with the
complexity of infrastructure management and scalability

Runtime Environment for Applications Development and
Data Processing Platforms
Examples: Windows Azure, Hadoop, Google AppEngine, Aneka
Platform as a Service
Virtualized Servers Storage and
Networking
Examples: Amazon EC2, S3, Rightscale, vCloud
Infrastructure as a Service
End user applications Scientific
applications
Office automation, Photo editing,
CRM, and Social Networking
Examples: Google Documents, Facebook, Flickr, Salesforce
Software as a Service
Web 2.0
Interfaces
Cloud Computing Reference Model

Characteristics and Benefits
• No up-front commitments
• On-demand access
• Nice pricing
• Simplified application acceleration and scalability
• Efficient resource allocation
• Energy efficiency
• Seamless creation and use of third-party services
The characteristics that bring benefits to both cloud service consumers
(CSCs) and cloud service providers (CSPs). These characteristics are:

Challenges Ahead
• Dynamic Provisioning of Cloud Computing Services
• Security and Privacy
• Legal issues
• Performance and Bandwidth Cost
• Reliability and Availability

Historical Development of Cloud Computing
• One of the main principles of cloud computing from
SAAS (Software as a service) to provide storage on
demand, is that the computing capacity varies
immediately and transparently with the customer’s
need.
• The idea of renting computing services by leveraging
large distributed computing facilities has been around
for long time. It started from 1950’s itself

Evolution of cloud technologies
• Distributed Systems
A distributed system is a collection of independent computers that appears to its
users as a single system and also it acts as a single computer.
The main and primary motive of distributed systems is to share resources and to
utilize them better.

Distributed Systems
This is absolutely true in case of cloud computing because in cloud computing we are
sharing the single resource by paying rent.
The resource is single because the definition of cloud computing clearly states that in
cloud computing the single central copy of a particular software is stored in a server
(which is located on a anonymous location ) and users are accessing that on PAY PER
USE BASIS.

Mainframes
• A large high-speed computer, especially one supporting numerous workstations or
peripherals the central processing unit and primary memory of a computer.

Mainframes
• Mainframes were powerful, highly reliable computers specialized for large data
movement and massive input/output (I/O) operations.
• They were used by large organizations for bulk data processing tasks such as online
transactions, enterprise resource planning, and other operations involving the
processing of significant amounts of data.
• No system shutdown was required to replace failed components
• Now their popularity and deployments have reduced.

Clusters
• A computer cluster consists of a set of loosely or tightly connected computers that
work together so that, in many respects, they can be viewed as a single system.
computer clusters have each node set to perform the same task, controlled

Clusters
• Cluster computing started as a low-cost alternative to the use of
mainframes and supercomputers.
• These machines are connected by a high-bandwidth network and
controlled by specific software tools that manage them as a single
system.
• commodity machines are used here, they were cheaper than
mainframes and made high-performance computing available to a large
number of groups, including universities and small research labs.
• clusters could be easily extended if more computational power was
required.

Grids
• Grid computing is the collection of computer resources from multiple
locations to reach a common goal. The grid can be thought of as a
distributed system with non- interactive workloads that involve a large
number of files.
• Grid computing appeared in the early 1990s as an evolution of cluster
computing.
• In an analogy to the power grid, grid computing proposed a new approach to
access large computational power, huge storage facilities, and a variety of
services.

Grids
• Several developments made possible the diffusion of computing grids:
(a) clusters became quite common resources;
(b) they were often underutilized;
(c) new problems were requiring computational power that went beyond the
capability of single clusters;
(d) The improvements in networking and the diffusion of the Internet made
possible long distance, high-bandwidth connectivity

..

Virtualization
• Virtualization is another core technology for cloud computing.
• It encompasses a collection of solutions allowing the abstraction of some of the
fundamental elements for computing, such as hardware, runtime environments,
storage, and networking.
• Virtualization confers that degree of customization and control that makes cloud
computing appealing for users and, at the same time, sustainable for cloud services
providers.
• These environments are called virtual because they simulate the interface that is
expected by a guest. The most common example of virtualization is hardware
virtualization.

Virtualization

Web 2.0
• The second stage of development of the Internet characterized especially change
from static web pages to dynamic or user-generated content and the growth of
social media.
• Web 2.0 brings interactivity and flexibility into Webpages, providing enhanced user
experience by gaining Web based access to all the functions that are normally found
in desktop applications.
• Examples of Web2.0applicationsare Google Documents, Google Maps, Flickr,
Facebook, Twitter, YouTube, delicious, Blogger, and Wikipedia

Web 2.0
• The Web is the primary interface through which cloud computing delivers its
services.
• Web encompasses a set of technologies and services that facilitate interactive
information sharing, collaboration, user-centered design, and application
composition
• These capabilities are obtained by integrating a collection of standards and
technologies such as
• XML, Asynchronous JavaScript and XML (AJAX), Web Services, and others.

Service-Oriented Computing (SOC)
• supports the development of rapid, low-cost, flexible,
interoperable, and evolvable applications and systems

• Service-oriented computing introduces and diffuses two important concepts, which are
also fundamental to cloud computing: quality of service(QoS) and Software-as-a-
Service(SaaS).
• The interaction with Webs services happens through Simple Object Access Protocol
(SOAP)
• One of the most popular expressions of service orientation is represented by Web
Services (WS)
• Web services are software components that expose functionalities accessible using a
method invocation pattern that goes over the Hypertext Transfer Protocol (HTTP).
• Using SOAP and WSDL over HTTP, Web services become platform independent and
accessible to the World Wide Web

Utility Oriented Computing
The Computer Utility, is a service provisioning model in which a service provider
makes infrastructure needed, and charges them forspecific usage rather than a
Flat rate.

Building Cloud Computing Environment
The creation of cloud computing environments encompasses both the development of
applications and systems that leverage cloud computing solutions and the creation of
frameworks, platforms, and infrastructures delivering cloud computing services

Infrastructure and System

Computing Platform and Technologies
• AWS offers comprehensive cloud IaaS services ranging from virtual compute,
storage, and networking to complete computing stacks.
• AWS is mostly known for its compute and storage-on- demand services, namely
Elastic Compute Cloud (EC2) and Simple Storage Service (S3).
• S3 is organized into buckets those are containers of objects that are stored in binary
form.
• Users can store objects of any size, from simple files to entire disk images, and have
them accessible from everywhere.

CloudComputingArchitecture Module 1 ppt.pptx

Google App Engine
• Google App-Engine is a scalable runtime environment mostly devoted to executing
Web applications.
• AppEngine provides both a secure execution environment and a collection of
services that simplify the development of scalable and high-performance Web
applications.
• Developers can build and test applications on their own machines using the
AppEngine software development kit (SDK), which replicates the production runtime
environment and helps test and profile applications.

Microsoft Azure
• Paas
• Web role (to host application), worker role (container of applications for work load processing)
and virtual machine role (provides virtual environment).
• https://azure.microsoft.com

Hadoop
Hadoop an open source, Java- programming framework that does processing and
storage of extremely large data.
• It is develop by google
• It provides two fundamental operations for data processing
• Map and reduce
• Map: transforms and synthesis the input
• Reduce: aggregates the output
• https://cloud.google.com/hadoop
• http://hadoop.apache.org/

Hadoop

Salesforce
• salesforce.com, inc. is an American cloud computing company headquartered in San
Francisco, California. It provides SAAS
• Force.com allows developers to create applications by composing ready-to-use
blocks;
• a complete set of components supporting all the activities of an enterprise are
available.
• https://www.salesforce.com/in

Manjarasoft Aneka
• Manjrasoft Aneka is a cloud application platform for rapid creation of scalable
applications and their deployment on various types of clouds in a seamless and
elastic manner.
• It supports a collection of programming abstractions for developing applications
and a distributed runtime environment
• Three major market segments identified in the reference model: Infrastructure-
as-a- Service, Platform-as-a-Service, and Software-as-a-Service.

Manjarasoft Aneka
• Aneka is a platform and a framework for developing distributed applications on
the Cloud.
• One of the key features of Aneka is the ability of providing different ways for
expressing distributed applications by offering different programming models;
• http://www.manjrasoft.com/products.html

Virtualization
• Virtualization is the creation of a virtual environment rather than actual version of
something, such as an operating system, a server, a storage device or network
resources
• One of the fundamental Concepts of Cloud Computing

Why are virtualized environments so popular today?
– Increased performance and computing capacity
●
PCs are having immense computing power.
– Underutilized hardware and software resources
●
Limited use of increased performance & computing capacity.
– Lack of space
●
Continuous need for additional capacity.
– Greening initiatives
●
Reduce carbon footprints
●
Reducing the number of servers, reduce power consumption.
– Rise of administrative costs
●
Power, cooling, H/W monitoring and defective replacement, server setup and updates, backups,
●
Virtualization can help reduce the number of required servers for a given workload, thus reducing the cost of
the administrative personnel.

●
Three major components of Virtualized Environments
– Guest – system component that interacts with
Virtualization Layer.
– Host – original environment where guest runs.
– Virtualization Layer – recreate the same or different
environment where guest will run.

Virtualization Layer
Virtual Hardware Virtual Storage Virtual Networking
Software Emulation
Host Physical Hardware Physical Storage Physical Networking
Guest Applications
Applications
Virtual Image
Virtualization Reference Model

Characteristics of Virtual Environment
• Increased Security
• Managed Execution
 - Sharing
 - Aggregation
 - Emulation
 - Isolation
• Portability

Increased Security
– Ability to control the execution of a guest
– Guest is executed in emulated environment.
– Virtual Machine Manager control and filter the activity of the guest.
– Hiding of resources.
– Having no effect on other users/guest environment.

Managed Execution types
– Sharing
●
Creating separate computing environment within the same host.
●
Underline host is fully utilized.
– Aggregation
●
A group of separate hosts can be tied together and represented as single virtual host.
– Emulation
●
Controlling & Tuning the environment exposed to guest.
– Isolation
●
Complete separate environment for guests
●
Performance tuning

Managed Execution

Portability
– portability applies in different ways according to the specific type of virtualization
considered
– Application Development Cycle more flexible and application deployment very
straight forward
– Availability of system is with you ready to use.
– The guest is packaged into a virtual image that, in most cases, can be safely moved
and executed on top of different virtual machines.
– Virtual images are generally proprietary formats that require a specific virtual
machine manager to be executed.

Taxonomy of Virtualization Techniques
• Virtualization is mainly used to emulate execution environment ,
storage and networks.
• Execution Environment classified into two :-
– Process-level – implemented on top of an existing operating system.
– System-level – implemented directly on hardware and do not or
minimum requirement of existing operating system

Execution Virtualization
●
It includes all techniques that aim to emulate an execution environment that is
separate from the one hosting the virtualization layer.
●
It can be implemented directly on top of the hardware by the operating system,
an application, or libraries dynamically or statically linked to an application
image.
●
It defines the interfaces between the levels of abstractions, which hide
implementation details.
●
Virtualization techniques actually replace one of the layers and intercept the calls
that are directed towards it.

Machine Reference Model
●
Virtualizing an execution environment at different levels of the computing stack
requires a reference model
●
It defines the interfaces between the levels of abstractions, which hide
implementation details.
●
virtualization techniques actually replace one of the layers and intercept the calls
that are directed toward it.

●
Hardware is expressed in terms of the Instruction Set Architecture (ISA).
– ISA for processor, registers, memory and the interrupt management.
– ISA is the interface between hardware and software.
– It is important to the OS developer and developers of applications that directly
manage the underlying hardware

●
Application Binary Interface (ABI)
– It separates the OS layer from the application and libraries which are
managed by the OS.
– This interface allows portability of applications and libraries across
– operating systems
– System calls defined here
– Allows probabilities of applications and libraries across OS.
●
Application programming interface (API)
– This interfaces applications to libraries and/or the underlying operating
system.

ISA: Security Classes
The instruction set exposed by the hardware has been divided into
different security classes that define who can operate with them.
•Non-privileged instructions
• Instructions that can be used without interfering with other tasks
because they do not access shared resources.
• Ex: floating, fixed-point, and arithmetic instructions.

ISA: Security Classes
●
Privileged instructions
– That are executed under specific restrictions and are mostly
used for sensitive operations, which expose (behavior-
sensitive) or modify (control-sensitive) the privileged state.
●
Behavior-sensitive – operate on the I/O
●
Control-sensitive – alter the state of the CPU register.

Privileged Hierarchy: Security Ring
●
Ring-0 is in most privileged level used by the kernel.
●
Ring-1 & 2 used by the OS-level services
●
Ring -3 in the least privileged level , used by the user.
●
system support two levels :-
– Ring 0 – supervisor mode: executes without any restriction, (Its called
master mode or kernel mode.)
– Ring 3 – user mode: There are restrictions to control the machine-level
resources.

Hardware-level virtualization
●
It is a virtualization technique that provides an abstract execution
environment in terms of computer hardware on top of which a guest
OS can be run.
●
It is also called as system virtualization.

Hardware-level virtualization

Hypervisors
●
A fundamental element of hardware virtualization is the hypervisor, or
virtual machine manager (VMM).
●
Hypervisor runs above the supervisor mode.
●
It recreates a h/w environment.
●
It is a piece of s/w that enables us to run one or more VMs on a
physical server(host).
●
Two major types of hypervisor
– Type –I, Type-II

Type-I Hypervisor
●
It runs directly on top of the hardware.
●
Takes place of OS.
●
Directly interact with the ISA exposed by the underlying hardware.
●
Also known as native virtual machine

Type-II Hypervisor
●
It require the support of an operating system to provide virtualization
services.
●
Programs managed by the OS.
●
Emulate the ISA of virtual h/w.
●
Also called hosted virtual machine.

Virtual Machine Manager (VMM)
●
Main Modules :-
– Dispatcher
●
Entry Point of VMM
●
Reroutes the instructions issued by VM instance.
– Allocator
●
Deciding the system resources to be provided to the VM.
●
Invoked by dispatcher
– Interpreter
●
Consists of interpreter routines
●
Executed whenever a VM executes a privileged instruction.
●
Trap is triggered and the corresponding routine is executed.

Virtual Machine Manager (VMM)

Criteria of VMM
●
Equivalence – same behavior as when it is executed directly on the
physical host.
●
Resource control – it should be in complete control of
virtualized resources.
●
Efficiency – a statistically dominant fraction of the machine instructions
should be executed without intervention from the VMM

Theorems
●
Popek and Goldberg provided a classification of the
instruction set and proposed three theorems that define the
properties that hardware instructions need to satisfy in
order to efficiently support virtualization.
●
Classification of IS-
– Privileged Instructions
●
Trap if the processor is in user mode
– Control sensitive Instructions

Theorems-1
●
Theorems 1
– For any conventional third-generation computer, a VMM may be
constructed if the set of sensitive instructions for that computer is a
subset of the set of privileged instructions.

Theorems
●
Theorems 2
– A conventional third-generation computers is recursively
virtualizable if:
●
It is virtualizable and
●
A VMM without any timing dependencies can be constructed for it.

Theorems
●
Theorems 3
– A hybrid VMM may be constructed third- generation machine
in which the set of user- sensitive instructions is a subset of
the set of privileged instructions.
– In HVM, more instructions are interpreted rather than being
executed directly.

Hardware virtualization Techniques
●
CPU installed on the host is only one set, but each VM that runs on the host
requires their own CPU.
●
It means CPU needs to virtualized, done by hypervisor.

●
Hardware-assisted virtualization
– In this hardware provides architectural support for building a
VMM able to run a guest OS in complete isolation.
– Intel VT and AMD V extensions.
– Early products were using binary translation to trap some sensitive
instructions and provide an emulated version.
– Software emulation is significantly costly from the performance point
of view.

●
Full virtualization
– Ability to run program (OS) directly on top of a virtual machine and without any
modification.
– VMM require complete emulation of the entire underneath h/w
– Advantages
●
Complete isolation
●
Enhanced security
●
Ease of emulation of different architectures and coexistence
– Key challenge is interception of privileged instructions such as I/O,
– Since they change the state of the resource exposed by host. So provide virtual
environment for all the instructions.

●
Paravirtualization
– Not-transparent virtualization solution that allows implementing Thin VMM
– Expose software interface to the virtual machine that is slightly modified
from the host.
– Guest OS need to be modified.
– Aim is to provide the capability to demand the execution of performance
critical operation directly on host.
– Allows simply transfer the execution of instructions which were hard to
virtualized, directly to the host.
– Suitable for open source os.

Heading Goes Here
●
Partial virtualization
– Partial emulation of the underlying hardware
– Not allow complete isolation to guest OS.
– Address space virtualization is a common feature of
contemporary operating systems.
– Address space virtualization used in time- sharing system.

Operating system-level virtualization
●
It offers the opportunity to create different and separated execution
environments for applications that are managed concurrently.
●
No VMM or hypervisor
●
Virtualization is in single OS
●
OS kernel allows for multiple isolated user space instances
●
Good for server consolidation.
●
Ex. chroot operation changes root directory to parent and child specific directory
●
Example for os virtualization are FreeBSDJails, OpenVZ etc.

Programming language-level virtualization
●
It is mostly used to achieve ease of deployment of application, managed execution and
portability across different platform and OS.
●
It consists of a virtual machine executing the byte code of a program, which is the result of the
compilation process.
●
Produce a binary format representing the machine code for an abstract architecture.
●
It was introduced in 1996 for implementation of Basic Combined Programming Language (BCPL)
an ancestors of C language.
●
Example
– Java platform – Java virtual machine (JVM)
– .NET provides Common Language Infrastructure (CLI)
●
They are stack-based virtual machines
●
Register based VM’s which are close to underlying architecture Eg: Parrot used to support
execution of PERL

Advantage of programming/process- level VM
●
Provide uniform execution environment
across different platforms.
●
This simplifies the development and deployment efforts.
●
Allow more control over the execution of programs.
●
Security; by filtering the I/O operations
●
Easy support for sandboxing

Application-level virtualization
●
It is a technique allowing applications to run in runtime
environments that do not natively support all the features
required by such applications.
●
In this, applications are not installed in the expected runtime
environment.
●
This technique is most concerned with :-
– Partial file system
– Libraries
– Operating System component emulation

Strategies for Implementation Application-Level Virtualization
●
Emulation can be used to execute program binaries compiled for different h/w
architures
●
Two techniques can be implemented:-
– Interpretation -
●
In this every source instruction is interpreted by an emulator for executing native ISA instructions,
●
Minimal start up cost but huge overhead.
– Binary translation -
●
In this every source instruction is converted to native instructions with equivalent functions.
●
Block of instructions translated , cached and reused.
●
Large overhead cost , but over time it is subject to better performance.

Strategies for Implementation Application-Level Virtualization
(Cont..)
●
This is a good techniques for in case of missing libraries in host
OS.
●
It allows incompatible to run together,
●
It runs on the specific environment so it supports all the
applications which runs on specific environment.
●
Eg: Wine

Other Types: Storage Virtualization
●
It allows decoupling the physical organization of the h/w from its logical
representation.
●
Using Network based virtualization known as storage area network (SAN).

Network Virtualization
●
It combines h/w appliances and specific software for the creation and management
of a virtual n/w.
●
It can aggregate different physical networks into a single logical network.

Application Server Virtualization
• Application server virtualization abstracts a collection of application servers that
provide the same service as a single virtual application server
• Providing better quality of service rather than emulating a different environment

Virtualization and cloud computing
• Virtualization plays an important role in cloud computing
• Virtualization technologies are primarily used to offer configurable computing
environments and storage.
• Hardware virtualization is an enabling factor for solutions in the (IaaS) market
segment
• programming language virtualization is a technology leveraged in (PaaS) offerings.

Server consolidation and virtual machine migration

Pros and cons of virtualization
• Advantages of Virtualization
 Reduced spending
 Sandbox
 Portability
 Efficient use of resources.
 Easier backup and disaster recovery
 Better business continuity
 More efficient IT operations

Disadvantages of Virtualization
 Upfront costs.
 Software licensing considerations
 Possible learning curve
 Performance degradation
• Maintain the status of virtual processor
• Support of privileged instructions
• Support of paging within VM
 Inefficiency and degraded user experience
 Security holes and new threats

Technology examples
• Xen: paravirtualization
• VMware: full virtualization
• Microsoft Hyper-V

Xen: paravirtualization
• Xen is the most popular implementation of paravirtualization
• Xen is an open-source initiative
• Developed by a group of researchers at the University of Cambridge
• Citrix also offers it as a commercial solution,
• Xen-based technology is used for Desktop virtualization or server virtualization
• Xen Cloud Platform (XCP)
• high-performance execution of guest operating systems.
• This is done by modifying portions of the guest operating systems run by Xen

• A Xen-based system is managed by the Xen hypervisor, which runs in the highest
privileged mode.
• Guest operating systems are executed within domains, which represent virtual
machine instances.
• specific control software, which has Privileged access to the host and controls all
the other guest operating systems is executed in a special domain called Domain 0.
• Once VMM manager has completely booted, Domain 0 hosts HTTP server that
serves requests for virtual machine creation, configuration, and termination.
• https://www.xenproject.org/

x86 implementations support four different security levels
two levels: Ring 0 for the kernel code, and Ring 3 for user application and non privileged OS code.

• Paravirtualization needs the operating system codebase to be modified.
• Open-source operating systems such as Linux can be easily modified, since their
code is publicly available.

VMware: full virtualization
• Underlying hardware is replicated and made available to the guest operating system.
• Runs unaware of such abstraction layers and does not need to be modified.
• It support Type 1 and Type 2 Hypervisor.
• Full virtualization is possible through direct execution (for non sensitive instructions)
and binary translation (for sensitive instructions).
• VMware also provides additional tools and software that simplify the use of
virtualization technology either in a desktop environment or server environment.

• The use of dynamic binary translation was the only solution that allowed running x86
guest operating systems unmodified in a virtualized environment.
• x86 architecture design does not satisfy the first theorem of virtualization (sensitive
instructions are not subset of privileged instruction Set).
• This causes a different behavior when such instructions are not executed in Ring 0.
• In dynamic binary translation, the trap triggers the translation of the offending
instructions into an equivalent set of instructions that achieves the same goal without
generating exceptions.
• The major advantage is that guests can run unmodified in a virtualized environment.

• Disadvantage: Translating instructions at runtime introduces an additional overhead.
• CPU virtualization is only a component of a fully virtualized hardware environment.
• VMware achieves full virtualization by providing virtual representation of memory
and I/O devices.
• Memory virtualization can deeply impact performance without the appropriate
hardware support.(eg: OS management unit(MMU)).
• The translation look-aside buffer (TLB) in the virtual MMU directly maps physical
pages, and the performance slowdown only occurs in case of a TLB miss.

A full virtualization reference model

Microsoft Hyper-V
• Hyper-V is an infrastructure virtualization solution developed by Microsoft for server
virtualization.
• Hyper-V is currently shipped as a component of Windows Server 2008 R2 that installs
the hypervisor as a role within the server.
• Hyper-V supports multiple and concurrent execution of guest operating systems by
means of partitions.
• A partition is a completely isolated environment in which an operating system is
installed and run.

Microsoft Hyper-V
• Hyper-V takes control of the hardware, and the host operating system becomes a
virtual machine instance with special privileges, called the parent partition.
• The parent partition (also called the root partition) is the only one that has direct
access to the hardware.
• It runs the virtualization stack, hosts all the drivers required to configure guest
operating systems, and creates child partitions through the hypervisor.
• Child partitions are used to host guest operating systems and do not have access to
the underlying hardware.

Microsoft Hyper-V
The hypervisor is logically defined by the following components:
• Hypercalls interface: This is the entry point for all the partitions for the execution of
sensitive instructions and the parent partition uses this interface to create child partitions.
• Memory service routines (MSRs): It control the memory and its access from partitions
and the hypervisor uses the I/O MMU to fast-track access to devices from partitions by
translating virtual memory addresses.
• Advanced programmable interrupt controller (APIC): It is an interrupt controller, and it
manages the signals coming from the underlying hardware when some event occurs
• Each virtual processor is equipped with a synthetic interrupt controller (SynIC), The
hypervisor is responsible for dispatching the physical interrupts to the synthetic
interrupt controllers.

Microsoft Hyper-V
• Scheduler: It schedules the virtual processors to run on available physical processors. It
controlled by policies that are set by the parent partition.
• Address manager: It is used to manage the virtual network addresses that are allocated
to each guest operating system.
• Partition manager: It is in charge of performing partition creation, finalization,
destruction, enumeration, and configurations.

Enlightened I/O and synthetic devices
• Enlightened I/O provides an optimized way to perform I/O operations, allowing guest
operating systems to leverage an inter partition communication channel.
• There are three fundamental components:
• VMBus: This channel and defines the protocol for communication between partitions.
• Virtual Service Providers(VSPs): These are kernel-level drivers that are deployed in
the parent partition and provide access to the corresponding hardware devices.
• Virtual Service Clients(VSCs): It represent the virtual device drivers (also called
synthetic drivers) seen by the guest operating systems in the child partitions.

END OF MODULE 1

CloudComputingArchitecture Module 1 ppt.pptx

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CloudComputingArchitecture Module 1 ppt.pptx