Chapeter 2 introduction to cloud computing

Introduction to
Cloud Computing
Prakash G Khaire
Assistant Professor
The Mandvi Education Society Institute of Computer Studies

Definitions
• Cloud Computing is a paradigm of computing and
a new way of thinking about IT industry.
• It is not any specific technology, and due to its
evolving nature its definition is also evolving.

Definitions
• A scientific definition is proposed by the GRIDS Lab
the University of Melbourne
“A cloud is a type of parallel and distributed system consisting of a
collection of interconnected and virtualized computers that are dynamically
provisioned and presented as one or more unified computing resources based
on service level agreements established through negotiation between the service
provider and consumers.”

Definitions
• The NIST (National Institute of Standards and
Technology) definition is as follows
“Cloud Computing is a model for enabling 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 release with minimal management
effort or service provider interaction. This cloud model is composed of
five essential characteristics, three service models and four deployment
model.”

Central Ideas Behind Cloud Computing
Cloud
Computing
Utility
Computing
SLASOA

• The combination of utility computing, SOA and SLA
provides scalability, elasticity, availability, reliability,
manageability, interoperability, performance
optimization and accessibility portability.
• Cloud users can classified based on the
functionalities serve.
1. User’s Perspectives
2. Provider’s perspective

1. User’s Perspectives
o Users are more interested in the “service” they get rather than how the get it.
o Their only concern is the quality of service, because they do not own any physical
infrastructure
o they want to pay for only as much as they haveused.
2. Provider’s perspective
o Cloud provides use the following three main enabling techniques to help
users benefit from cloud computing.
• Virtualization
• Parallelized and distributed computing
• Web Service

Central Ideas Behind Cloud Computing –
Utility Computing
• Utility computing provides a service provisioning model.
• The service provider makes the infrastructure and
computing resources available to its customers.
• The customers then use it as per their requirement and
make a monthly usage payment for computing, storage
and network resources just as they would do for any
other utility service.
• From a computer science perspective, service is what
we connect together through web service.

Functionalities of Service
• A service should be well defined
• A service should be autonomous
• A service should be independent and not
depend on the circumstances or state of
other services.

Service-Oriented Architecture
• SOA is a collection of various services that
communicate with each other.
• It is loosely coupled services that can be used for
multiple business requirements.
• It enables full flexibility in designing services, which
helps during system integration model.
• SOA is usually implemented by a web service
model.

Service Level Agreement
• SLA is a mutual agreement between consumers
and service provider that defines detailed service
offerings, delivery time, quality of service (QoS) and
scope or constraints of the offered services.
• Common content in the Contract
o Uptime and downtime ratio
o System throughput
o Response time

Properties and Characteristics of
Cloud Computing
High scalability and elasticity
High availability and reliability
High manageability and interoperability
High accessibility and portability
High performance and optimzation

Scalability and Elasticity
1. Scalability
o Means a process or network is its ability to quickly handle any unexpected rise in
the volumeof work within a gap or discontinuity in servicedelivery.
o “Increasing”thecapacity to meet the “increasing” workload.
o Two Basic Category
• Horizontal Scaling : It is done by adding more machines into your pool of
resources
• Vertical Scaling : It is done by adding more power (CPU, RAM) to your existing
machine.
2. Elasticity
1. In cloud environment,elasticity represents responsivenessof demand and supply to
price changes.
2. If demand movesby more than the price change, it is described as relatively
elastic.

Methods for Achieving Scalability and Elasticity
• Two methods are commonly used
oDynamic Provisioning
oMulti-tenant Design

Dynamic Provisioning
• Means those instances when a virtual server is provisioned on the
basis of the customer’s requirement through a cloud administration
console, client application or through the network and system
administrator.
• The following two problems may occur
o Underestimated system utilization, results in under-provision
o Overestimated system utilization, results in low utilization.

Multi-Tenant Design
• Multi-tenant design architecture is a kind of software
architecture that can handle multiple client
organizations or where a software that runs on one
server has the ability to serve multiple client requests
simultaneously.
• Following are requirements of the multi-tenant design
o Customization : Multi-tenant applications are generally mandatory to deliver
good quality customization to support every organization’s objectives and
goal
o QoS : Multi-tenant applications must offer high levels of security and
robustness.

Availability and Reliability
• Availability
o The ration of time a system or component is functional to the total time it is
required to the total time it is required or probable to function.
• Reliability
• It means the capacity of a system hardware or software to perform
constantly without fail according to defined specifications.

Method of Achieving and Reliability
• Fault-tolerant system
• System resilience
• Reliable system security

Fault-tolerant system
• It is special property of a system which empowers it to continue
operating properly even in the event of the failure of some of its
components.
• Characteristics of Fault-tolerant system
o Not even a single chance of failure
o Detection of fault and isolation for the component that failed
o Control of fault for preventing dissemination of failure
o Accessibility of reversion modes

System Resilience
• It is a system’s capability for providing and maintaining an
adequate level of services despite faults and challenges with
existing operations.
• Resiliency preserves the system capability to return to its
original state after meetingtrouble.
• If a risk event hits a system offline, an extremely resilient system
willreturn to work and function as planned as soon as possible.
• Following are some risk events
o If power is lost at a plant for two days, then how would our system recover?
o If a key service is lost because a database becomes corrupt, can the business recover?

System Resilience
• Disaster Recovery
o It is a procedure and a set of policies regarding preparing for
recovering or maintenance of technology infrastructure
critical to an organization after a human-induced or natural
disaster.
o Following are some common strategies for disaster recovery
• Backup : Replication of data
• Preparing : Enabling local mirroring systems, hard disk
protection system and uninterruptible power supply (UPS)

System Security
• It is the most important concern in information security
• Following are some main security issues related to cloud
computing.
o Data Protection : To provide protected data, cloud providers must ensure that
one customer’s data is properly segregated from that of another
o Application Security : Cloud Provides must guarantee that applications
available as a service via the cloud are secure
o Identity management : Every enterprise must have its individual identity
management system to control access to information and computing
resources
o Privacy : Providers must guarantee that all critical data are masked and that
only authorized users have access to data in its entirely.

Manageability and Interoperability
• Manageability
o It means managing entire cloud systems.
o System management in cloud computing is much more dependent on
overall network and offered services management
• Interoperability
o It is a characteristics of a system or product which provides an easy-to-
understand interface or platform to enable work with any other services
and platforms with unlimited access.

Method of achieving
Manageability and Interoperability
• Following are the three main methods
1. System Control Automation
2. System State Monitoring
3. Automatic Billing

Control Automation
• Its purpose is to develop computer systems capable of self-
management, to overcome the rapidly growing complexity of
computing system administration and to diminish the barrier that
complexity poses to any additional development.
• Functional areas of control automation
o Self-Configuration : Automatic Configuration of components
o Self-Healing : Enablement mechanism of automatic detection of any
system faults and reaction of those faults
o Self-Optimization : Enablement mechanism for monitoring and controlling
of system resources for ensuring optimal resource utilization with specified
requirements.
o Self-Protection : Active identification of all kinds of threats and
enablement of self protected from random attacks.

System Monitoring
• A distributed system for collecting and storing state
data in cloud computing.
• Certain things that need to be always monitored
o Status of physical machine and virtual machine
o Detail resource utilization metrics
o Networkand bandwidth performance
o System logs
o Billingdetails

Automatic Billing System
• A cloud environment usually follows the pay-per-use
model (users pay according to their usage).
• A cloud provider must first decide the price for the
list of service usage.
• It has to record the supply or service usage of each
other, and then charge them by these records.

Methods of Knowing User’s Usage
• Get the information by means of a monitoring
system
• Repeatedly calculate the total amount of money a
user should pay and automatically request money
from user’s banking account.

Accessibility and Portability
• Accessibility : It is the word used to define the
degree to which a device, product or service is
accessible to as many people as possible.
• Service Portability : It is the capacity to access
services with the help of devices, anywhere,
constantly with mobility provision and dynamic
variation to resource variations.

Methods for achieving
Accessibility and Portability
• Consistent Access :
o It offers a set of cloud services just as we access general media.
o Users can access cloud services from any operating system or any platform
directly across the globe.
o Web browser technique is the most extensive platform in any intelligent
electronic devices.
• Thin Client
o It is a program that depends completely on another computer for achieving
all traditional roles
o It does not contain any internal memory so thin clients utilize different browsers
such as Internet Explorer, Google Chrome or Mozilla Firefox.
o It is widely used because it is low priced, provides security, consumes less
power, is easily reparable and replaceable etc.

Performance and Optimization
• Cloud providers make use of powerful infrastructure or other
highlighting resources to develop a high performance and
highly optimized environment, and then bring the entire
bunch of services to cloud users.
• Methods for achieving Performance and Optimization
o Parallel processing
o Load balancing
o Job Schedular

Parallel Processing
• It is an advanced method of computation where
multiple calculations are carried out simultaneously.
• A big computation problem is first split into small
ones and then further divided into even smaller
problems.

Load Balancing
• It is a procedure to allocate workload equally
across two or more computers, network links, hard
drives, CPUs or additional resources to receive best
resource utilization, decrease response time,
maximize throughput and prevent overload.
• Load balancing is necessary to improve resource
utilization, system performance and energy
efficiency.

Job Scheduler
• It is a kind of software application that is responsible
for unattended background executions, usually
known for historical details such as batch
processing.

Benefits of Cloud Computing
• Following are the key benefits of cloud computing
from the market and enterprises perspective
o Reduction of initial upfront investment
o Reduction of capital expenditure
o Improvement in industrial specialization
o Improvement in resource utilization

Traditional IT and Cloud Computing with
respect to business
Matrices Traditional IT Cloud Computing
Initial Investment The enterprise takes the risk A cloud reduces the risk
Infrastructure The enterprise maintains the
infrastructure
A cloud provider
maintains the
infrastructure
Time Period Deployment duration is
lengthy
Business readiness is
quick

respect to Capital Expenditure
Business Focus The enterprise needs to own its
IT department
A cloud provider takes
care of everything
Payment The enterprise pays for all
assets and human resources
The enterprise pays as
per the service used
Time Duration Establishment time is lengthy Business readiness is
quick

respect to Industrial Specialization
Collaboration The enterprise needs to take
care of everything
The enterprise minds its
own business
Management and
Control
The enterprise works with
inadequate manageability
A cloud provider
provides professional
control
Industry
Relationship
It is a standalone enterprise It is a win-win
partnership

respect to Resource Utilization
IT Resource
Utilization
IT resource underutilization is
a problem
Enables sharing to
increase the
consumption of IT
resources
Power
Consumption
Wastage of power and cooling
system is a problem
A cloud system should
be worldwide optimized

Benefits of Cloud Computing
• Following are the key benefits of cloud computing
from the Ends users and individuals perspective
o Reduction of local computing power.
o Reduction of local storage power
o Availability of a variety of thin client devices in
daily life.

respect to End-user experience
Hardware
Necessity
The user wants to buy
powerful hardware
Only necessary
hardware is required for
connecting to the
Internet
Software
Necessity
Application has to be installed
in the local computer
No installation is
necessary on the system
Portability It is not a really portable It is natively portable

respect to Storage
Storage Space Limited to local disk, may be
less consumed
Dynamically allocated
on demand
Storage Data
Consistency
Hard to retain data consistency Data Consistency
continued by cloud
Availability Consistent user backup Cloud service assurance

respect to end devices
Small Device
Intelligence
Functionalities are restricted
because of their power
consumption
Transfer computing-
intensive jobs into cloud,
and then wait for results
Computing power Can be accessed only through a
desk top computer
Can be accessed via
small smart devices

Service Models
• Cloud computing combines various services. It is the
same as choosing a service according to your
needs.
o Constructing a new house
o Buying a house
o Staying in a hotel

What if you want to have an IT department
• Similar to constructing a new house
o Iaas – Infrastructure as a Service, which allows to rent some virtualized
infrastructure and develop your own IT system from among those resources,
which you may control entirely.
• Similar to buying a house
o PaaS – Platform as a Service solution, which lets you develop your IT system
through one cloud platform without at all bothering about lower-level resource
management.
• Similar to staying in a hostel
o SaaS – Software as a Service (SaaS) solution, which lets you pre-existed IT
system solutions that were provided by some cloud application providers,
without ever having to know anything about how these services were
accoomplished

Cloud Service Models
Infrastructure as a Service
Platform as a Service
Software as a Service

• IaaS means renting hardware.
• The IaaS service offers raw infrastructure resources
that are the base requirements for the
establishment of a data center such as
o Network
o Storage
o processing power
o Memory
o Bandwidth
o operating system installations
o overall network and system administration.

• The most revolutionary benefits of IaaS is that
customers do not require to manage or to control
the system and network administrations related
tasks.
• Customers can dynamically make provisions for all
their infrastructure resources on demand basis.
• They can select a particular resource and
customize it according to their requirements.

• Following are some IaaS providers and their services
o Amazon’s EC2 or Elastic Compute Cloud
o Rackspace’s Cloud Servers
o Flexiant’s FlexiScale
o GoGrid’s Cloud Hosting and Storage
o Google’s Compute Engine
o Microsoft’s Azure

The billing models also contain
o Daily or Montly subscription plans
o “Pay-as-you-go” Billing
o Addition to data transfer
o Server RAM hours (GoGrid)
o Separate cloud storage billing

• Platform is a computing platform offered through
the web.
• Web applications can be created and codes
deployed without purchasing any license software
or hardware.
• PaaS offerings are specific to web developers, web
designers and application developers.

• “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
application hosting environment configurations.”

• Some PaaS Providers and the environment they
provide are as follows
o Microsoft’s Azure
o Google’s App Engine
o Salesforce.com’s force.com
o VM Ware’s cloud foundary
o Engine Yard

• Main services of PaaS experienced by users
1. Programming IDE
1. Users can use programming development environment to develop that offered
servicesin PaaS.
2. This IDE integrates all development functionalities together which are supporting it
form runtime environment.
3. The IDE comes with developers tools such as debugger, profiler and testing
environment.
2. System Control Interface
1. Police based control
2. Workflow control

• SaaS offers to the consumers applications over the
web that run on a cloud infrastructure.
• These applications are available from several client
devices via a thin client such as web browser, for
example email.
• Consumers need not worry about the fundamental
cloud infrastructure, servers, storage, operating
system, application abilities and procedures of
deployement.

• The SaaS service model delivers the services as
applications to the consumer using standard interfaces.
• The services run on top of a cloud infrastructure, which is
obscure to the consumers.
• In a SaaS offering, the cloud provider is only responsible
for the control and management of the underlying
infrastructure, the operating system and the appications.
• Subscribes can only control some user specific and
application related settings.

SaaS Providers and theirs offerings ???

System architecture of IaaS
Resource Management Interface System monitoring interface
Virtualization layer
Computing System Network System Storage System
User

• Virtualization is the main enabling techniques in the
IaaS system architecture.
• The virtualization technique move the OS onto the
hypervisor.
• With the help of this technique, multiple OS share
the physical hardware and offer different services.
• It increases availability, utilization, security and
accessibility.

1. Virtual Machine : As IaaS provider must be capable of controlling system
states. Memory utilization, CPU loading and internal network loading are
some examples of virtual machines.
2. Virtual Storage : An IaaS provider must be capable of controlling
and monitoring the storage states of each virtual storage. Some
examples are duplication of data information, effective usage of
virtual space management and access bandwidth
3. Virtual Network : An IaaS provider should be capable of controlling
and monitoring network states of every virtual network; for example,
connectivity between networks, bandwidth of virtual networks and
balancing of load of each network.

System architecture of PaaS
Programming IDE System control Interface
• Policy Based
• Workflow
Programming
APIs
• Development
tools
Runtime Environment
Scalability and
Elasticity
Availability and
Reliability
Performance
Optimization
Manageability
and
Interoperability
Computing Resource Network Storage Resource

System architecture of PaaS
• Platform services provide an end-to-end
application development environment for
developers.
• The main enabling technique is the Runtime
Environment Design.
• Run time environment refers to the gathering of
software services accessible i.e a collection of
program libraries.

System architecture of SaaS
Web-based application Web Portal
General
Application
Business
Application
Scientific
Application
Government
Application
Commercial Platform Open Source Platform Others
Mobile User Desktop/Laptop User Business User

Deployment Model
Community
Cloud
Private
Cloud
Public
Cloud
Hybrid
Cloud

Public Cloud
Public cloud computing services are available to anyone,
from anywhere, and at any time through the Internet.
This computing infrastructure is hosted at the vendor’s
workplace.
The end user cannot view the infrastructure.
The computing infrastructure is shared between
companies.
The Service provider makes the resources such as storage
and applications available to the public over the WWW.

Public Cloud
Basic characteristics of Public Cloud
Uniformly designed infrastructure
Common policies
Resources occupied as a Share
Multi-tenantscenario – infrastructure rented or leased
Economics of scale

Private Cloud
Here the computing infrastructure is dedicated to the customer
and is not shared with any other companies.
They are costly and highly secure than public clouds.
Private clouds may be hosted externally as well as in their own
premise hosted clouds.
Public clouds guarantee a fair management and the respect of
the customer’s privacy but still there are threat or as
unacceptable risk that some organizations are not willing to
take, institution like government and military agencies.
Loss of control where virtual IT infrastructure resides could
open the way to other problematic situations.

Private Cloud
Basic Characteristics of Private Cloud
Non-uniformly designed infrastructure
Custom and modified policies
Specific resources
Internal Infrastructure
End-to-end control

Community Cloud
The cloud infrastructure is shared between the companies of the
same community.
For example, all the government organizations in a city can
share the same cloud but not the non-governmental
organizations.
The users of a specific community cloud fall into a well-
identified community, sharing same concerns or needs-they can
be government bodies, industries, or even simple users but all of
them focus on the same issues for their interaction with the
cloud.

Hybrid Cloud
Organizations can submit less valued applications in public
cloud and high valued applications in the private cloud.
The combination is known as hybrid cloud.
Cloud bursting is used to define a system where the
organization uses its own infrastructure for normal usage
and cloud is used for peak times.

Challenges with Cloud Computing
• Security
• Quality of Services
• Integration of Services
• High network response time
• The problem of metering

Cloud Supporting Services
• Apart from the three prominent services IaaS, PaaS, & SaaS, there are
various services offered by cloud providers for enhancing
collaboration and effective utilizationof resource
• Cloud Storage Service –
o Object storage it is a medium to store unlimited amount of data from any
location using a simple web interface and stored objects are highly
scalable, available, secure and quickly accessible.
o Block Storage services are mostly fit for use as the primary storage for a file
system, database or any other application that requires regular granular
updates and access to raw, unformatted block-level storage.

Cloud Supporting Services
• Cloud Database Service – It provides resizable capacity while
taking care of cheaper cost and less database management efforts
so that we can focus on developing applications rather than on
database administration-related tasks.
• Cloud Load-Balancing Service – It handles unexpected traffic of
hosted applications or websites and uneven load.
• Cloud Backup and Disaster-Recovery Services – A plan can be
built if some good architectural approach is being followed when
designing cloud infrastructure.

Management and Administration of
Cloud Services
• A company has to ask itself many questions about
the efficiency of various services. Here are list of
issues to consider.
o What vendors are available to solve your problem?
o How effective are the providers in managing their individual environment?
o How do these vendors handle an outage?
o Do they offer frequent services always?
o What is their experience in negotiation with customer issues?

Management and Administration of
Cloud Services
• Business Continuity Management
o Business across the globe are never interrupted and continuity is always
maintained.
• System Reliability
o It is mainly essential for the IT industry to allow administration systems that
let them monitor every dimension of the services they are receiving.
• Fault Tolerance
o System or solution architect to design a fault tolerant application that can
leverage maximum and optimal utilization of cloud resources.
• Response Time
o The response time creates the first impact of service offerings.

Chapeter 2 introduction to cloud computing

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Chapeter 2 introduction to cloud computing