_Cloud_Computing_Overview.pdf

CLOUD COMPUTING
Cloud Computing - Overview
PROF. SOUMYA K. GHOSH
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING
IIT KHARAGPUR

Introduction
• The ACM Computing Curricula 2005defined "computing" as
"In a general way, we can define computing to mean any goal-oriented
activity requiring, benefiting from, or creating computers. Thus,
computing includes designing and building hardware and software
systems for a wide range of purposes; processing, structuring, and
managing various kinds of information; doing scientific studies using
computers; making computer systems behave intelligently; creating
and using communications and entertainment media; finding and
gathering information relevant to any particular purpose, and so on.
The list is virtually endless, and the possibilities are vast."
2

Cloud Computing Course - Overview
I. Introduction to Cloud Computing
i. Overview of Computing
ii. Cloud Computing (NIST Model)
iii. Properties, Characteristics & Disadvantages
iv. Role of Open Standards
II. Cloud Computing Architecture
i. Cloud computing stack
ii. Service Models (XaaS)
a. Infrastructure as a Service(IaaS)
b. Platform as a Service(PaaS)
c. Software as a Service(SaaS)
iii. Deployment Models
III. Service Management in Cloud Computing
i. Service Level Agreements(SLAs)
ii. Cloud Economics
IV. Resource Management in Cloud Computing

Cloud Computing Course (contd.)
V. Data Management in Cloud Computing
i. Looking at Data, Scalability & Cloud Services
ii. Database & Data Stores in Cloud
iii. Large Scale Data Processing
VI. Cloud Security
i. Infrastructure Security
ii. Data security and Storage
iii. Identity and Access Management
iv. Access Control, Trust, Reputation, Risk
VII. Case Study on Open Source and Commercial Clouds, Cloud Simulator
VIII. Research trend in Cloud Computing, Fog Computing

Trends in Computing
• Distributed Computing
• Grid Computing
• Cluster Computing
• Utility Computing
• Cloud Computing
5

Centralized vs. Distributed Computing
7
Early computing was performed on a single processor. Uni-processor computing
can be called centralized computing.

Distributed Computing/System?
• Distributed computing
– Field of computing science that studies distributed system.
– Use of distributed systems to solve computational problems.
• Distributed system
– Wikipedia
• There are several autonomous computational entities,
each of which has its own local memory.
• The entities communicate with each other by message
passing.
– Operating System Concept
• The processors communicate with one another through various
communication lines, such as high-speed buses or telephone
lines.
• Each processor has its own local memory.
8

Example Distributed Systems
• Internet
• ATM (bank) machines
• Intranets/Workgroups
• Computing landscape will soon consist of ubiquitous
network-connected devices
9

Computers in a Distributed System
• Workstations: Computers used by end-users to perform
computing
• Server Systems: Computers which provide resources and
services
• Personal Assistance Devices: Handheld computers connected to
the system via a wireless communication link.
10

Common properties of Distributed Computing
– Fault tolerance
• When one or some nodes fails, the whole system can still work fine except performance.
• Need to check the status of each node
– Each node play partial role
• Each computer has only a limited, incomplete view of the system.
• Each computer may know only one part of the input.
– Resource sharing
• Each user can share the computing power and storage resource in the system with other
users
– Load Sharing
• Dispatching several tasks to each nodes can help share loading to the whole system.
– Easy to expand
• We expect to use few time when adding nodes. Hope to spend no time if possible.
– Performance
• Parallel computing can be considered a subset of distributed computing
11

Why Distributed Computing?
• Nature of application
• Performance
– Computing intensive
• The task could consume a lot of time on computing. For example,
Computation of Pi value using Monte Carlo simulation
– Data intensive
• The task that deals with a large amount or large size of files. For example,
Facebook, LHC(Large Hadron Collider) experimental data processing.
• Robustness
– No SPOF (Single Point Of Failure)
– Other nodes can execute the same task executed on failed
node.
12

CLOUD COMPUTING
CLOUD COMPUTING OVERVIEW (contd..)
IIT KHARAGPUR

Why Distributed Computing?
• Nature of application
• Performance
– Computing intensive
• The task could consume a lot of time on computing. For example,
Computation of Pi value using Monte Carlo simulation
– Data intensive
• The task that deals with a large amount or large size of files. For example,
Facebook, LHC(Large Hadron Collider) experimental data processing.
• Robustness
– No SPOF (Single Point Of Failure)
– Other nodes can execute the same task executed on failed
node.
2

Distributed applications
• Applications that consist of a set of processes that are distributed across a
network of machines and work together as an ensemble to solve a
common problem
• In the past, mostly “client-server”
• Resource management centralized at the server
• “Peer to Peer” computing represents a movement towards more “truly”
distributed applications
3

Clients invoke individual servers
4

A typical distributed application based on peer processes
5

Grid Computing?
• Pcwebopedia.com
– A form of networking. unlike conventional networks that focus on communication
among devices, grid computing harnesses unused processing cycles of all computers in
a network for solving problems too intensive for any stand-alone machine.
• IBM
– Grid computing enables the virtualization of distributed computing and data resources
such as processing, network bandwidth and storage capacity to create a single system
image, granting users and applications seamless access to vast IT capabilities. Just as
an Internet user views a unified instance of content via the Web, a grid user essentially
sees a single, large virtual computer.
• Sun Microsystems
– Grid Computing is a computing infrastructure that provides dependable,
consistent, pervasive and inexpensive access to computational capabilities
7

Electrical Power Grid Analogy
Electrical Power Grid
• Users (or electrical appliances) get access to
electricity through wall sockets with no care or
consideration for where or how the electricity
is actually generated.
• “The power grid” links together power plants
of many different kinds
Grid
• Users (or client applications) gain access to computing
resources (processors, storage, data, applications, and
so on) as needed with little or no knowledge of where
those resources are located or what the underlying
technologies, hardware, operating system, and so on
are
• “The Grid" links together computing resources (PCs,
workstations, servers, storage elements) and provides
the mechanism needed to access them.
8

Grid Computing
1. Share more than information: Data, computing power, applications in
dynamic environment, multi-institutional, virtual organizations
2. Efficient use of resources at many institutes. People from many institutions
working to solve a common problem (virtual organisation).
3. Join local communities.
4. Interactions with the underneath layers must be transparent and seamless
to the user.
9
When v use

Need of Grid Computing?
• Today’s Science/Research is based on computations, data analysis, data
visualization & collaborations
• Computer Simulations & Modelling are more cost effective than
experimental methods
• Scientific and Engineering problems are becoming more complex & users
need more accurate, precise solutions to their problems in shortest possible
time
• Data Visualization is becoming very important
• Exploiting under utilized resources
10
Mathematical modeling of systems

Type of Grids
• Computational Grid: These grids provide secure access to huge pool of shared processing
power suitable for high throughput applications and computation intensive computing.
• Data Grid: Data grids provide an infrastructure to support data storage, data discovery, data
handling, data publication, and data manipulation of large volumes of data actually stored in
various heterogeneous databases and file systems.
• Collaboration Grid: With the advent of Internet, there has been an increased demand for
better collaboration. Such advanced collaboration is possible using the grid. For instance,
persons from different companies in a virtual enterprise can work on different components of
a CAD project without even disclosing their proprietary technologies.
12

Type of Grids
• Network Grid: A Network Grid provides fault-tolerant and high-performance communication
services. Each grid node works as a data router between two communication points,
providing data-caching and other facilities to speed up the communications between such
points.
• Utility Grid: This is the ultimate form of the Grid, in which not only data and computation
cycles are shared but software or just about any resource is shared. The main services
provided through utility grids are software and special equipment. For instance, the
applications can be run on one machine and all the users can send their data to be processed
to that machine and receive the result back.
13

Grid Components
Source:KajariMazumdar “GRID:ComputingWithoutBorders” DepartmentofHighEnergyPhysicsTIFR,Mumbai. 14

What is Cluster Computing?
• A cluster is a type of parallel or distributed computer
system, which consists of a collection of inter-connected
stand-alone computers working together as a single
integrated computing resource .
• Key components of a cluster include multiple standalone
computers (PCs, Workstations, or SMPs), operating systems,
high-performance interconnects, middleware, parallel
programming environments, and applications.
16

Cluster Computing?
• Clusters are usually deployed to improve speed and/or reliability
over that provided by a single computer, while typically being much
more cost effective than single computer the of comparable speed
or reliability
• In a typical cluster:
– Network: Faster, closer connection than a typical
network (LAN)
– Low latency communication protocols
– Loosely coupled than SMP
17

Types of Cluster
• High Availability or Failover Clusters
• Load Balancing Cluster
• Parallel/Distributed Processing Clusters
18

Cluster Components
• Basic building blocks of clusters are broken down into multiple
categories:
• Cluster Nodes
• Cluster Network
• Network Characterization
19

Key Operational Benefits of Clustering
• System availability: offer inherent high system availability due to
the redundancy of hardware, operating systems, and applications.
• Hardware fault tolerance: redundancy for most system
components (eg. disk-RAID), including both hardware and
software.
• OS and application reliability: run multiple copies of the OS and
applications, and through this redundancy
• Scalability. adding servers to the cluster or by adding more clusters
to the network as the need arises or CPU to SMP.
• High performance: (running cluster enabled programs)
20

“Utility” Computing ?
• Utility Computing is purely a concept which cloud computing practically implements.
• Utility computing is a service provisioning model in which a service provider makes
computing resources and infrastructure management available to the customer as
needed, and charges them for specific usage rather than a flat rate.
• This model has the advantage of a low or no initial cost to acquire computer resources;
instead, computational resources are essentially rented.
• The word utility is used to make an analogy to other services, such as electrical power,
that seek to meet fluctuating customer needs, and charge for the resources based on
usage rather than on a flat-rate basis. This approach, sometimes known as pay-per-use
22

• "Utility computing" has
usually envisioned some
form of virtualization so
that the amount of
storage or computing
power available is
considerably larger than
that of a single time-
sharing computer.
Source:AlanMcSweeney,“TheEconomicsofUtilityComputing”
23

a) Pay-for-use Pricing Business Model
b) Data Center Virtualization and Provisioning
c) Solves Resource Utilization Problem
d) Outsourcing
e) Web Services Delivery
f) Automation
24

Utility Computing Example
On-Demand Cyber Infrastructure
25

Utility Solution – Your Perspective
Consumer Provider
Pricing
Security
Resource
Utilization
Service
Assurance
SLA
Technology
Refresh
vs
System
Admins
Application
Sizing
Service
Procurement
Infrastructure
Procurement
Equipment
Maintenance
Consultants
Contractor
Management
Availability
Capacity
Planning
Source: Perry Boster, “Utility Computing for Shared Services”,
Massachusetts Digital Government Summit, September 23rd, 2004 –
Boston, MA
26

Utility Computing Payment Models
• Same range of charging models as other utility providers: gas, electricity, telecommunications, water,
television broadcasting
− Flat rate
− Tiered
− Subscription
− Metered
− Pay as you go
− Standing charges
• Different pricing models for different customers based on factors such as scale, commitment and
payment frequency
• But the principle of utility computing remains
• The pricing model is simply an expression by the provider of the costs of provision of the resources and a
profit margin
27

Risks in a UC World
• Data Backup
• Data Security
• Partner Competency
• Defining SLA
• Getting value from charge back
28

Source: http://www.smallbiztechnology.com/archive/2011/09/wait-what-is-cloud-computing.html/
US National Institute of Standards and Technology defines Computing as
“ 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. ”
Cloud Computing
30

1
Cloud Computing - Overview
Prof. Soumya K Ghosh
Department of Computer Science and Engineering
IIT KHARAGPUR

US National Institute of Standards and Technology (NIST) defines Computing as:
“ 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. ”
Cloud Computing
3
http://www.smallbiztechnology.com/archive/2011/09/wait-what-is-cloud-computing.html

Essential Characteristics
• On-demand self-service
• A consumer can unilaterally provision computing capabilities, such as server time and network storage, as
needed automatically without requiring human interaction with each service provider.
• Broad network access
• Capabilities are available over the network and accessed through standard mechanisms that promote use by
heterogeneous thin or thick client platforms (e.g., mobile phones, tablets, laptops, and workstations).
• Resource pooling
• The provider’s computing resources are pooled to serve multiple consumers using a multi-tenant model,
with different physical and virtual resources dynamically assigned and reassigned according to consumer
demand.
4

Cloud Characteristics
• Measured Service
– Cloud systems automatically control and optimize resource use by leveraging a metering
capability at some level of abstraction appropriate to the type of service (e.g., storage,
processing, bandwidth, and active user accounts). Resource usage can be
– monitored, controlled, and reported, providing transparency for both the provider and
consumer of the utilized service.
• Rapid elasticity
– Capabilities can be elastically provisioned and released, in some cases automatically, to
scale rapidly outward and inward commensurate with demand. To the consumer, the
capabilities available for provisioning often appear to be unlimited and can be
appropriated in any quantity at any time.
5

Common Characteristics
• Massive Scale
• Resilient Computing
• Homogeneity
• Geographic Distribution
• Virtualization
• Service Orientation
• Low Cost Software
• Advanced Security
6

Cloud Services Models
• Software as a Service (SaaS)
 The capability provided to the consumer is to use the provider’s applications running on a cloud infrastructure. The applications
are accessible from various client devices through either a thin client interface, such as a web browser (e.g., web-based email),
or a program interface.
 The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems,
storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration
settings.
 e.g: Google Spread Sheet
• Cloud Infrastructure as a Service (IaaS)
 The capability provided to provision processing, storage, networks, and other fundamental computing resources
 Consumer can deploy and run arbitrary software
 e.g: Amazon Web Services and Flexi scale.
7

Cloud Services Models
Platform as a Service (PaaS)
 The capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or
acquired applications created using programming languages, libraries, services, and tools supported by the
provider.
 The consumer does not manage or control the underlying cloud infrastructure including network, servers,
operating systems, or storage, but has control over the deployed applications and possibly configuration
settings for the application-hosting environment.
8

Types of Cloud (Deployment Models)
• Private cloud
The cloud infrastructure is operated solely for an organization.
e.g Window Server 'Hyper-V'.
• Community cloud
The cloud infrastructure is shared by several organizations and supports a specific goal.
• Public cloud
The cloud infrastructure is made available to the general public
e.g Google Doc, Spreadsheet,
• Hybrid cloud
The cloud infrastructure is a composition of two or more clouds (private, community, or public)
e.g Cloud Bursting for load balancing between clouds.
10

Cloud and Virtualization
• Virtual Workspaces:
– An abstraction of an execution environment that can be made dynamically available to
authorized clients by using well-defined protocols,
– Resource quota (e.g. CPU, memory share),
– Software configuration (e.g. OS).
• Implement on Virtual Machines (VMs):
– Abstraction of a physical host machine,
– Hypervisor intercepts and emulates instructions from VMs, and allows management of VMs,
– VMWare, Xen, KVM etc.
• Provide infrastructure API:
– Plug-ins to hardware/support structures
Hardware
OS
App App App
Hypervisor
OS OS
Virtualized Stack
11

Virtual Machines
• VM technology allows multiple virtual machines to run on a single
physical machine.
Hardware
Virtual Machine Monitor (VMM) / Hypervisor
Guest OS
(Linux)
Guest OS
(NetBSD)
Guest OS
(Windows)
VM VM VM
App
App App
App
App
Xen
VMWare
• Performance: Para-virtualization (e.g. Xen) is very close to raw physical
performance!
12

Virtualization in General
• Advantages of virtual machines:
– Run operating systems where the physical hardware is unavailable,
– Easier to create new machines, backup machines, etc.,
– Software testing using “clean” installs of operating systems and software,
– Emulate more machines than are physically available,
– Timeshare lightly loaded systems on one host,
– Debug problems (suspend and resume the problem machine),
– Easy migration of virtual machines (shutdown needed or not).
– Run legacy systems
13

Cloud-Sourcing
• Why is it becoming important ?
– Using high-scale/low-cost providers,
– Any time/place access via web browser,
– Rapid scalability; incremental cost and load sharing,
– Can forget need to focus on local IT.
• Concerns:
– Performance, reliability, and SLAs,
– Control of data, and service parameters,
– Application features and choices,
– Interaction between Cloud providers,
– No standard API – mix of SOAP and REST!
– Privacy, security, compliance, trust…
14

Cloud Storage
• Several large Web companies are now exploiting the fact that they have data
storage capacity that can be hired out to others.
– Allows data stored remotely to be temporarily cached on
desktop computers, mobile phones or other Internet-linked
devices.
• Amazon’s Elastic Compute Cloud (EC2) and Simple Storage Solution (S3) are well
known examples
15

Advantages of Cloud Computing
• Lower computer costs:
– No need of a high-powered and high-priced computer to run cloud computing's
web-based applications.
– Since applications run in the cloud, not on the desktop PC, your desktop PC does not
need the processing power or hard disk space demanded by traditional desktop
software.
– When you are using web-based applications, your PC can be less expensive, with a
smaller hard disk, less memory, more efficient processor...
– In fact, your PC in this scenario does not even need a CD or DVD drive, as no
software programs have to be loaded and no document files need to be saved.
16

• Improved performance:
– With few large programs hogging your computer's memory, you will see better
performance from your PC.
– Computers in a cloud computing system boot and run faster because they have fewer
programs and processes loaded into memory.
• Reduced software costs:
– Instead of purchasing expensive software applications, you can get most of what you
need for free.
• most cloud computing applications today, such as the Google Docs suite.
– better than paying for similar commercial software
• which alone may be justification for switching to cloud applications.
17

• Instant software updates
– Another advantage to cloud computing is that you are no longer faced with choosing
between obsolete software and high upgrade costs.
– When the application is web-based, updates happen automatically available the next time
you log into the cloud.
– When you access a web-based application, you get the latest version without needing to pay
for or download an upgrade.
• Improved document format compatibility.
– You do not have to worry about the documents you create on your machine being
compatible with other users' applications or OS.
– There are less format incompatibilities when everyone is sharing documents and
applications in the cloud.
18

• Unlimited storage capacity
– Cloud computing offers virtually limitless storage.
– Your computer's current 1 Tera Bytes hard drive is small compared to the hundreds of Peta
Bytes available in the cloud.
• Increased data reliability
– Unlike desktop computing, in which if a hard disk crashes and destroy all your valuable
data, a computer crashing in the cloud should not affect the storage of your data.
• if your personal computer crashes, all your data is still out there in the cloud, still accessible
– In a world where few individual desktop PC users back up their data on a regular basis,
cloud computing is a data-safe computing platform. For e.g. Dropbox, Skydrive
19

• Universal information access
– That is not a problem with cloud computing, because you do not take your
documents with you.
– Instead, they stay in the cloud, and you can access them whenever you have a
computer and an Internet connection
– Documents are instantly available from wherever you are.
• Latest version availability
– When you edit a document at home, that edited version is what you see when
you access the document at work.
– The cloud always hosts the latest version of your documents as long as you are
connected, you are not in danger of having an outdated version.
20

• Easier group collaboration
– Sharing documents leads directly to better collaboration.
– Many users do this as it is an important advantages of cloud computing
multiple users can collaborate easily on documents and projects
• Device independence
– You are no longer tethered to a single computer or network.
– Changes to computers, applications and documents follow you through the
cloud.
– Move to a portable device, and your applications and documents are still
available.
21

Disadvantages of Cloud Computing
• Requires a constant internet connection
– Cloud computing is impossible if you cannot connect to the Internet.
– Since you use the Internet to connect to both your applications and documents, if you do not
have an Internet connection you cannot access anything, even your own documents.
– A dead Internet connection means no work and in areas where Internet connections are few or
inherently unreliable, this could be a deal-breaker.
• Does not work well with low-speed connections
– Similarly, a low-speed Internet connection, such as that found with dial-up services, makes
cloud computing painful at best and often impossible.
– Web-based applications require a lot of bandwidth to download, as do large documents.
22

• Features might be limited
– This situation is bound to change, but today many web-based applications simply
are not as full-featured as their desktop-based applications.
• For example, you can do a lot more with Microsoft PowerPoint than with Google
Presentation's web-based offering
• Can be slow
– Even with a fast connection, web-based applications can sometimes be slower than
accessing a similar software program on your desktop PC.
– Everything about the program, from the interface to the current document, has to
be sent back and forth from your computer to the computers in the cloud.
– If the cloud servers happen to be backed up at that moment, or if the Internet is
having a slow day, you would not get the instantaneous access you might expect
from desktop applications.
23

• Stored data might not be secured
– With cloud computing, all your data is stored on the cloud.
• The questions is How secure is the cloud?
– Can unauthorized users gain access to your confidential data ?
• Stored data can be lost!
– Theoretically, data stored in the cloud is safe, replicated across multiple machines.
– But on the off chance that your data goes missing, you have no physical or local backup.
• Put simply, relying on the cloud puts you at risk if the cloud lets you down.
24

• HPC Systems
– Not clear that you can run compute-intensive HPC applications that use MPI/OpenMP!
– Scheduling is important with this type of application
• as you want all the VM to be co-located to minimize communication latency!
• General Concerns
– Each cloud systems uses different protocols and different APIs
• may not be possible to run applications between cloud based systems
– Amazon has created its own DB system (not SQL 92), and workflow system (many
popular workflow systems out there)
• so your normal applications will have to be adapted to execute on these platforms.
25
High performance system

Evolution of Cloud Computing
Business drivers for adopting cloud
computing

Reasons
• The main reason for interest in cloud computing is due to the fact that
public clouds can significantly reduce IT costs.
• From and end user perspective cloud computing gives the illusion of
potentially infinite capacity with ability to scale rapidly and pay only for
the consumed resource.
• In contrast, provisioning for peak capacity is a necessity within private
data centers, leading to a low average utilization of 5-20 percent.
27

IaaS Economics
In house server Cloud server
Purchase Cost $9600 (x86,3QuadCore,12GB
RAM, 300GB HD)
0
Cost/hr (over 3 years) $0.36 $0.68
Cost ratio: Cloud/In house 1.88
Efficiency 40% 80%
Cost/Effective hr $0.90 $0.85
Power and cooling $0.36 0
Management Cost $0.10 $0.01
Total cost/effective hr $1.36 $0.86
Cost ratio: In house/Cloud 1.58
Source: Enterprise Cloud Computing by Gautam Shroff
28

Benefits for the end user while using public cloud
• High utilization
• High scalability
• No separate hardware procurement
• No separate power cost
• No separate IT infrastructure administration/maintenance required
• Public clouds offer user friendly SLA by offering high availability (~99%) and also
provide compensation in case of SLA miss.
• Users can rent the cloud to develop and test prototypes before making major
investments in technology
29

Benefits for the end user while using public cloud
• In order to enhance portability from one public cloud to another, several
organizations such as Cloud Computing Interoperability Forum and Open
Cloud Consortium are coming up with standards for portability.
• For e.g. Amazon EC2 and Eucalyptus share the same API interface.
• Software startups benefit tremendously by renting computing and storage
infrastructure on the cloud instead of buying them as they are uncertain
about their own future.
30

Benefits for Small and Medium Businesses (<250 employees)
Source: http://www.microsoft.com/en-us/news/presskits/telecom/docs/SMBCloud.pdf
31

Benefits of private cloud
• Cost of 1 server with 12 cores and 12 GB RAM is far lower than the
cost of 12 servers having 1 core and 1 GB RAM.
• Confidentiality of data is preserved
• Virtual machines are cheaper than actual machines
• Virtual machines are faster to provision than actual machines
32

Economics of PaaS vs IaaS
• Consider a web application that needs to be available 24X7, but
where the transaction volume is unpredictable and can vary rapidly
• Using an IaaS cloud, a minimal number of servers would need to be
provisioned at all times to ensure availability
• In contrast, merely deploying the application on PaaS cloud costs
nothing. Depending upon the usage, costs are incurred.
• The PaaS cloud scales automatically to successfully handle increased
requests to the web application.
Source: Enterprise Cloud Computing by Gautam Shroff
33

PaaS benefits
• No need for the user to handle scaling and load balancing of
requests among virtual machines
• PaaS clouds also provide web based Integrated Development
Environment for development and deployment of application on
the PaaS cloud.
• Easier to migrate code from development environment to the
actual production environment.
• Hence developers can directly write applications on the cloud and
don’t have to buy separate licenses of IDE.
34

SaaS benefits
• Users subscribe to web services and web applications instead of
buying and licensing software instances.
• For e.g. Google Docs can be used for free, instead of buying
document reading softwares such as Microsoft Word.
• Enterprises can use web based SaaS Content Relationship
Management applications, instead of buying servers and installing
CRM softwares and associated databases on them.
35
Customer relationship management

Benefits, as perceived by the IT industry
36

Factors driving investment in cloud
Source: http://www.cloudtweaks.com/2012/01/infographic-whats-driving-investment-in-cloud-
computing/
37

Factors driving investment in cloud
Source: http://www.cloudtweaks.com/2012/01/infographic-whats-driving-investment-in-cloud-computing/
38

Purpose of cloud computing in organizations
• Providing an IT platform for business processes involving multiple organizations
• Backing up data
• Running CRM, ERP, or supply chain management applications
• Providing personal productivity and collaboration tools to employees
• Developing and testing software
• Storing and archiving large files (e.g., video or audio)
• Analyzing customer or operations data
• Running e-business or e-government web sites
Source: http://askvisory.com/research/key-drivers-of-cloud-computing-activity/
39
Enterprise resource planning

Purpose of cloud computing in organizations
• Analyzing data for research and development
• Meeting spikes in demand on our web site or internal systems
• Processing and storing applications or other forms
• Running data-intensive batch applications (e.g., data conversion, risk modeling,
graphics rendering)
• Sharing information with the government or regulators
• Providing consumer entertainment, information and communication (e.g., music,
video, photos, social networks)
40
Source: http://askvisory.com/research/key-drivers-of-cloud-computing-activity/
Put an end

Top cloud applications that are driving cloud adaptation
• Mail and Messaging
• Archiving
• Backup
• Storage
• Security
• Virtual Servers
• CRM (Customer Relationship Management)
• Collaboration across enterprises
• Hosted PBX (Private Branch Exchange)
• Video Conferencing
Source: http://www.itnewsafrica.com/2012/09/ten-drivers-of-cloud-computing-for-south-african-businesses/
41

CLOUD COMPUTING
CLOUD COMPUTING ARCHITECTURE
IIT KHARAGPUR

Context: High Level Architectural Approach
Source: http://www.sei.cmu.edu/library/assets/presentations/Cloud%20Computing%20Architecture%20-%20Gerald%20Kaefer.pdf
2

Major building blocks of Cloud Computing
Architecture
• Technical Architecture:
– Structuring according to XaaS stack
– Adopting cloud computing paradigms
– Structuring cloud services and cloud components
– Showing relationships and external endpoints
– Middleware and communication
– Management and security
• Deployment Operation Architecture:
– Geo-location check (Legal issues, export control)
– Operation and Monitoring
Ref: http://www.sei.cmu.edu/library/assets/presentations/Cloud%20Computing%20Architecture%20-%20Gerald%20Kaefer.pdf
3

Cloud Computing Architecture - XaaS
4

XaaS Stack views: Customer view vs Provider view
5

Microsoft Azure vs Amazon EC2
6

Architecture for elasticity
7

Service Models (XaaS)
 Combination of Service-Oriented Infrastructure (SOI) and cloud
computing realizes to XaaS.
 X as a Service (XaaS) is a generalization for cloud-related services
 XaaS stands for "anything as a service" or "everything as a service“
 XaaS refers to an increasing number of services that are delivered
over the Internet rather than provided locally or on-site
 XaaS is the essence of cloud computing.
8

Source: Cloud Security and Privacy: An Enterprise Perspective on Risks and Compliance by Tim Mather and Subra Kumaraswamy
10

 Most common examples of XaaS are
 Software as a Service (SaaS)
 Platform as a Service (PaaS)
 Infrastructure as a Service (IaaS)
 Other examples of XaaS include
 Business Process as a Service (BPaaS)
 Storage as a service (another SaaS)
 Security as a service (SECaaS)
 Database as a service (DaaS)
 Monitoring/management as a service (MaaS)
 Communications, content and computing as a service (CaaS)
 Identity as a service (IDaaS)
 Backup as a service (BaaS)
 Desktop as a service (DaaS)
11

Requirements of CSP (Cloud Service Provider)
• Increase productivity
• Increase end user satisfaction
• Increase innovation
• Increase agility
12

• Broad network access (cloud) + resource pooling (cloud) +
business-driven infrastructure on-demand (SOI) + service-
orientation (SOI) = XaaS
• Xaas fulfils all the 4 demands!
Source: Understanding the Cloud Computing Stack: PaaS, SaaS, IaaS © Diversity Limited, 2011
13

Classical Service Model
Storage
Servers
Network
O/S
Middleware
Virtualization
Data
Applications
Runtime
Managed
by
user
 All the Layers(H/W, Operating System, Development Tools, Applications) Managed by the
Users
 Initial IT budget and resources.
 Users bears the costs of the hardware, maintenance and technology.
 Each system is designed and funded for a specific business activity: custom build-to-order
 Systems are deployed as a vertical stack of “layers” which are tightly coupled, so no single
part can be easily replaced or changed
 Prevalent of manual operations for provisioning, management
 Result: Legacy IT
Source: Dragan , “XaaS as a Modern Infrastructure for eGoverement Busines Model in the Republic of Croatia”
14
ADR MOV SSN

Key impact of cloud computing for IT function:
From Legacy IT to Evergreen IT
Dedicated Infrastructure
Application
End-user devices
Simplified IT Stack
Dedicated Infrastructure
Application
End-user devices
Simplified IT Stack
Legacy IT Evergreen IT
15

Client Server Architecture
Source:Wikipedia
17

Client Server Architecture
Source:Wikipedia
2

Client server architecture
• Consists of one or more load balanced servers
servicing requests sent by the clients
• Clients and servers exchange message in
request-response fashion
• Client is often a thin client or a machine with
low computational capabilities
• Server could be a load balanced cluster or a
stand alone machine.
3

Three Tier Client-Server Architecture
Source: Wikipedia
4

Client Server model vs. Cloud model
Client server model Cloud computing model
• Simple service model where
server services client
requests
• May/may not be load
balanced
• Scalable to some extent in a
cluster environment.
• No concept of virtualization
• Variety of complex service
models, such as, IaaS, PaaS,
SaaS can be provided
• Load balanced
• Theoretically infinitely
scalable
• Virtualization is the core
concept
5

Cloud Services
Source : http://www.opengroup.org/soa/source-book/socci/extend.htm#figure2
6

Cloud service models
Source: http://www.cs.helsinki.fi/u/epsavola/seminaari/Cloud%20Service%20Models.pdf
7

Simplified description of cloud service models
 SaaS applications are designed for end users and are
delivered over the web
 PaaS is the set of tools and services designed to make
coding and deploying applications quickly and efficiently
 IaaS is the hardware and software that powers it all –
servers, storage, network, operating systems
Source: http://broadcast.rackspace.com/hosting_knowledge/whitepapers/Understanding-the-Cloud-Computing-Stack.pdf
8

Transportation Analogy
• By itself, infrastructure isn’t useful – it just sits there waiting
for someone to make it productive in solving a particular
problem. Imagine the Interstate transportation system in
the U.S. Even with all these roads built, they wouldn’t be
useful without cars and trucks to transport people and
goods. In this analogy, the roads are the infrastructure and
the cars and trucks are the platform that sits on top of the
infrastructure and transports the people and goods. These
goods and people might be considered the software and
information in the technical realm
9

Software as a Service
• SaaS is defined as software that is deployed over the internet.
With SaaS, a provider licenses an application to customers
either as a service on demand, through a subscription, in a
“pay-as-you-go” model, or (increasingly) at no charge when
there is opportunity to generate revenue from streams other
than the user, such as from advertisement or user list sales.
10

SaaS characteristics
• Web access to commercial software
• Software is managed from central location
• Software is delivered in a ‘one to many’ model
• Users not required to handle software upgrades and patches
• Application Programming Interfaces (API) allow for integration
between different pieces of software.
11

Applications where SaaS is used
• Applications where there is significant interplay between
organization and outside world. E.g. email newsletter campaign
software
• Applications that have need for web or mobile access. E.g. mobile
sales management software
• Software that is only to be used for a short term need.
• Software where demand spikes significantly. E.g. Tax/Billing
softwares.
• E.g. of SaaS: Sales Force Customer Relationship Management (CRM)
software
12
Put an end

Applications where SaaS may not be the best
option
• Applications where extremely fast processing of
real time data is needed
• Applications where legislation or other regulation
does not permit data being hosted externally
• Applications where an existing on-premise solution
fulfills all of the organization’s needs
13

Platform as a Service
• Platform as a Service (PaaS) brings the benefits that
SaaS bought for applications, but over to the software
development world. PaaS can be defined as a
computing platform that allows the creation of web
applications quickly and easily and without the
complexity of buying and maintaining the software and
infrastructure underneath it.
• PaaS is analogous to SaaS except that, rather than being
software delivered over the web, it is a platform for the
creation of software, delivered over the web.
14

Characteristics of PaaS
 Services to develop, test, deploy, host and maintain applications in the same
integrated development environment. All the varying services needed to fulfill the
application development process.
 Web based user interface creation tools help to create, modify, test and deploy
different UI scenarios.
 Multi-tenant architecture where multiple concurrent users utilize the same
development application.
 Built in scalability of deployed software including load balancing and failover.
 Integration with web services and databases via common standards.
 Support for development team collaboration – some PaaS solutions include
project planning and communication tools.
 Tools to handle billing and subscription management
15

Scenarios where PaaS is used
 PaaS is especially useful in any situation where multiple developers
will be working on a development project or where other external
parties need to interact with the development process
 PaaS is useful where developers wish to automate testing and
deployment services.
 The popularity of agile software development, a group of software
development methodologies based on iterative and incremental
development, will also increase the uptake of PaaS as it eases the
difficulties around rapid development and iteration of software.
 PaaS Examples: Microsoft Azure, Google App Engine
16

Scenarios where PaaS is not ideal
• Where the application needs to be highly portable in terms
of where it is hosted.
• Where proprietary languages or approaches would impact
on the development process
• Where a proprietary language would hinder later moves to
another provider – concerns are raised about vendor lock
in
• Where application performance requires customization of
the underlying hardware and software
17

Infrastructure as a Service
• Infrastructure as a Service (IaaS) is a way of
delivering Cloud Computing infrastructure –
servers, storage, network and operating systems
– as an on-demand service.
• Rather than purchasing servers, software,
datacenter space or network equipment, clients
instead buy those resources as a fully outsourced
service on demand.
18

Characteristics of IaaS
• Resources are distributed as a service
• Allows for dynamic scaling
• Has a variable cost, utility pricing model
• Generally includes multiple users on a single
piece of hardware
19

Scenarios where IaaS makes sense
 Where demand is very volatile – any time there are significant spikes
and troughs in terms of demand on the infrastructure
 For new organizations without the capital to invest in hardware
 Where the organization is growing rapidly and scaling hardware
would be problematic
 Where there is pressure on the organization to limit capital
expenditure and to move to operating expenditure
 For specific line of business, trial or temporary infrastructural needs
20

Scenarios where IaaS may not be the best
option
• Where regulatory compliance makes the
offshoring or outsourcing of data storage and
processing difficult
• Where the highest levels of performance are
required, and on-premise or dedicated hosted
infrastructure has the capacity to meet the
organization’s needs
21

SaaS providers
22

Feature comparison of PaaS providers
23

Feature comparison of IaaS providers
24

XaaS
Managed
by
service
provider
Storage
Servers
Network
O/S
Middleware
Virtualization
Data
Applications
Runtime
Managed
by
user
Managed
by
user
Managed
by
service
provider
Storage
Servers
Network
O/S
Middleware
Virtualization
Applications
Runtime
Data
Managed
by
service
provider
Storage
Servers
Network
O/S
Middleware
Virtualization
Applications
Runtime
Data
SaaS PaaS IaaS
25
ADR MOV SSN

Role of Networking in cloud computing
• In cloud computing, network resources can be
provisioned dynamically.
• Some of the networking concepts that form the core
of cloud computing are Virtual Local Area Networks,
Virtual Private Networks and the different protocol
layers.
• Examples of tools that help in setting up different
network topologies and facilitate various network
configurations are OpenSSH, OpenVPN etc.
Source: http://www.slideshare.net/alexamies/networking-concepts-and-tools-for-the-cloud
26

Networking in different cloud models
Source: http://www.slideshare.net/alexamies/networking-concepts-and-tools-for-the-cloud
27

Network Function Virtualization
Source: https://portal.etsi.org/nfv/nfv_white_paper.pdf
Definition: “Network Functions Virtualisation aims to transform the way that network
operators architect networks by evolving standard IT virtualisation technology to
consolidate many network equipment types onto industry standard high volume servers,
switches and storage, which could be located in Datacentres, Network Nodes and in the end
user premises, as illustrated in Figure 1. It involves the implementation of network functions
in software that can run on a range of industry standard server hardware, and that can be
moved to, or instantiated in, various locations in the network as required, without the need
for installation of new equipment.”

Network Function Virtualization
Source: https://portal.etsi.org/nfv/nfv_white_paper.pdf

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