Introduction to Cloud computing

Class: FY.M.Sc Computer Science
Subject Code :- CSDT 114
Subject Name :- Cloud Computing
Chapter 1 – Introduction to Cloud
Computing
-By Anupama Alagannawar
MIT ACSC, Department of Computer Science 2020-21

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

Introduction to Cloud Computing
• Cloud Computing is the delivery of computing services such
as servers, storage, databases, networking, software,
analytics, intelligence, and more, over the Cloud (Internet).
Definition:
• Cloud Computing is a model for enabling ubiquitous,
Convenient, on-demand network access to a shared pool of
configurable computing resources that can be rapidly
provisioned and released with minimal management effort
or service provider interaction.
-NLIST
• A style of computing where a SCALABLE and ELASTIC IT-
enabled capabilities are provided as a service to external
customers using internet technologies.
- Garner INC.

Introduction to Cloud Computing

What is Cloud Computing?
• Cloud Computing is a general term used to describe a new class of
network based computing that takes place over the Internet,
– basically a step on from Utility Computing
– a collection/group of integrated and networked hardware,
software and Internet infrastructure (called a platform).
– Using the Internet for communication and transport provides
hardware, software and networking services to clients
• These platforms hide the complexity and details of the underlying
infrastructure from users and applications by providing very simple
graphical interface or API (Applications Programming Interface).

What is Cloud Computing?
• In addition, the platform provides on demand
services, that are always on, anywhere,
anytime and any place.
• Pay for use and as needed, elastic
– scale up and down in capacity and functionalities
• The hardware and software services are
available to
– general public, enterprises, corporations and
businesses markets

Cloud Summary
• Cloud computing is an umbrella term used to refer to
Internet based development and services
• A number of characteristics define cloud data,
applications services and infrastructure:
– Remotely hosted: Services or data are hosted on remote
infrastructure.
– Ubiquitous: Services or data are available from anywhere.
– Commodified: The result is a utility computing model
similar to traditional that of traditional utilities, like gas
and electricity - you pay for what you would want!

What is Cloud Computing
8
Adoptedfrom:EffectivelyandSecurelyUsingthe CloudComputing Paradigmbypeter Mell, Tim Grance
• Shared pool of configurable computing resources
• On-demand network access
• Provisioned by the Service Provider

Cloud Computing Characteristics
9
Common Characteristics:
Low Cost Software
Virtualization Service Orientation
Advanced Security
Homogeneity
Massive Scale Resilient Computing
Geographic Distribution
Essential Characteristics:
Resource Pooling
Broad Network Access Rapid Elasticity
Measured Service
On Demand Self-Service

Data Centre v/s Cloud Computing
• Cloud Computing provides an
alternative to the on-premises
datacentre. With an on-
premises datacentre, we have
to manage everything, such as
purchasing and installing
hardware, virtualization,
installing the operating
system, and any other
required applications, setting
up the network, configuring
the firewall, and setting up
storage for data. After doing
all the set-up, we become
responsible for maintaining it
through its entire lifecycle.
• But if we choose Cloud
Computing, a cloud vendor is
responsible for the hardware
purchase and maintenance.
They also provide a wide
variety of software and
platform as a service. We can
take any required services on
rent. The cloud computing
services will be charged based
on usage.

The cloud environment provides an easily accessible online
portal that makes handy for the user to manage the compute,
storage, network, and application resources.

Some Cloud Service providers

Advantages of cloud computing
• Cost: It reduces the huge capital costs of buying hardware
and software.
• Speed: Resources can be accessed in minutes, typically
within a few clicks.
• Scalability: We can increase or decrease the requirement
of resources according to the business requirements.
• Productivity: While using cloud computing, we put less
operational effort. We do not need to apply patching, as
well as no need to maintain hardware and software. So, in
this way, the IT team can be more productive and focus on
achieving business goals.
• Reliability: Backup and recovery of data are less expensive
and very fast for business continuity.
• Security: Many cloud vendors offer a broad set of policies,
technologies, and controls that strengthen our data
security.

Benefits of (Public) Clouds
• No upfront infrastructure investment
– No procuring hardware, setup, hosting, power, etc..
• On demand access
– Lease what you need and when you need..
• Efficient Resource Allocation
– Globallyshared infrastructure, can alwaysbe kept busy by serving users from
different time zones/regions...
• Nice Pricing
– Based on Usage, QoS, Supply and Demand, Loyalty, …
• Application Acceleration
– Parallelism for large-scale data analysis,what-if scenarios studies…
• Highly Availability, Scalable, and Energy Efficient
• Supports Creation of 3rd Party Services & Seamless offering
– Buildson infrastructure and follows similar Business model as Cloud

Disadvantages of cloud computing
• 1). Downtime
Downtime is often cited as one of the biggest
disadvantages of cloud computing. Since cloud computing
systems are internet-based, service outages are always an
unfortunate possibility and can occur for any reason.
• 2). Security and privacy
Although cloud service providers implement the best
security standards and industry certifications, storing data
and important files on external service providers always
opens up risks. Any discussion involving data must address
security and privacy, especially when it comes to managing
sensitive data.

• 3). Vulnerability to attack
In cloud computing, every component is online, which
exposes potential vulnerabilities. Even the best teams
suffer severe attacks and security breaches from time
to time. Since cloud computing is built as a public
service, it’s easy to run before you learn to walk. After
all, no one at a cloud vendor checks your
administration skills before granting you an account:
• 4). Limited control and flexibility
Since the cloud infrastructure is entirely owned,
managed, and monitored by the service provider, it
transfers minimal control over to the customer.

• 5). Vendor lock-in
Vendor lock-in is another perceived disadvantageof cloud computing. Easy
switching between cloud services is a service that hasn’t yet completely evolved,
and organizations mayfind it difficult to migrate their services from one vendor
to another. Differences between vendor platforms maycreate difficulties in
migrating from one cloud platform to another, which could equate to additional
costs and configuration complexities. Gaps or compromises made during
migration could also expose your data to additional security and privacy
vulnerabilities.
• 6). Cost concerns
Adopting cloud solutions on a small scale and for short-term projects can be
perceived as being expensive. However, the most significant cloud computing
benefit is in terms of IT cost savings. Pay-as-you-gocloud services can provide
more flexibility and lower hardware costs, but the overall price tag could end up
being higher than you expected. Until you are sure of what will work best for you,
it’s a good idea to experiment with a variety of offerings.

Types of Cloud /Cloud Deployment
Models

Types of Cloud Computing
• Public Cloud: The cloud resources that are owned and
operated by a third-party cloud service provider are termed
as public clouds. It delivers computing resources such as
servers, software, and storage over the internet
Whole computing infrastructure is located on the premises
of a cloud computing company that offers the cloud
service.
• Private Cloud: The cloud computing resources that are
exclusively used inside a single business or organization are
termed as a private cloud. A private cloud may physically be
located on the company’s on-site datacentre or hosted by a
third-party service provider.
Hosting all your computing infrastructure yourself and is
not shared. The security and control level is highest while
using a private network.

Types of Cloud Computing
• Hybrid Cloud:
It is the combination of public and private clouds,
which is bounded together by technology that allows
data applications to be shared between them. Hybrid
cloud provides flexibility and more deployment options
to the business.
using both private and public clouds, depending on
their purpose. You host your most important
applications on your own servers to keep them more
secure and secondary applications elsewhere.
• Community Cloud – A community cloud is shared
between organizations with a common goal or that fit
into a specific community (professional community,
geographic community, etc.).

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

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

Cloud Service Models
Software as a
Service (SaaS)
Platform as a
Service (PaaS)
Infrastructure as a
Service (IaaS)
Google App
Engine
SalesForce CRM
LotusLive

Different Cloud Computing Layers‫‏‬
Application Service
(SaaS)‫‏‬
Application Platform
Server Platform
Storage Platform Amazon S3, Dell, Apple, ...
3Tera, EC2, SliceHost,
GoGrid, RightScale, Linode
Google App Engine, Mosso,
Force.com, Engine Yard,
Facebook, Heroku, AWS
MS Live/ExchangeLabs, IBM,
Google Apps; Salesforce.com
Quicken Online, Zoho, Cisco
24

Services
Application
Development
Platform
Storage
Hosting
Cloud Computing Service Layers
Description
Services – Complete business services such as
PayPal, OpenID, OAuth, Google Maps, Alexa
Services
Application
Focused
Infrastructure
Focused
Application – Cloud based software that
eliminates the need for local installation such
as Google Apps, Microsoft Online
Storage – Data storage or cloud based NAS
such as CTERA, iDisk, CloudNAS
Development – Software development
platforms used to build custom cloud based
applications (PAAS & SAAS) such as SalesForce
Platform – Cloud based platforms, typically
provided using virtualization, such as Amazon
ECC, Sun Grid
Hosting – Physical data centers such as those
run by IBM, HP, NaviSite, etc.
25

Infrastructure as a service (IaaS)
• A vendor provides clients pay-as-you-go access to
storage, networking, servers and other
computing resources in the cloud.
• Iaas is also known as Hardware as a Service
(HaaS). It is one of the layers of the cloud
computing platform. It allows customers to
outsource their IT infrastructures such as servers,
networking, processing, storage, virtual
machines, and other resources. Customers access
these resources on the Internet using a pay-as-
per use model.

Infrastructure as a service (IaaS)
• In traditional hosting services, IT infrastructure was rented
out for a specific period of time, with pre-determined
hardware configuration. The client paid for the
configuration and time, regardless of the actual use. With
the help of the IaaS cloud computing platform layer, clients
can dynamically scale the configuration to meet changing
requirements and are billed only for the services actually
used.
• IaaS cloud computing platform layer eliminates the need
for every organization to maintain the IT infrastructure.

Services provided by IaaS
Compute: Computing as a Service includes virtual central
processing units and virtual main memory for the Vms that is
provisioned to the end- users.
Storage: IaaS provider provides back-end storage for storing files.
Network: Network as a Service (NaaS) provides networking
componentssuch as routers, switches,and bridges for the Vms.
Load balancers: It provides load balancing capability at the
infrastructure layer.

Advantages of IaaS cloud computing
layer
• There are the following advantages of IaaS computing layer -
• 1. Shared infrastructure
IaaS allows multiple users to share the same physical infrastructure.
• 2. Web access to the resources
Iaas allows IT users to access resources over the internet.
• 3. Pay-as-per-use model
IaaS providers provide services based on the pay-as-per-use basis.
The users are required to pay for what they have used.
• 4. Focus on the core business
IaaS providers focus on the organization's core business rather than
on IT infrastructure.
• 5. On-demand scalability
On-demand scalability is one of the biggest advantages of IaaS.
Using IaaS, users do not worry about to upgrade software and
troubleshoot the issues related to hardware components.

Top Iaas Providers who are providing
IaaS cloud computing platform

Platform as a Service | PaaS
• Platform as a Service (PaaS) provides a runtime
environment. It allows programmers to easily create, test,
run, and deploy web applications.
• You can purchase these applications from a cloud service
provider on a pay-as-per use basis and access them using
the Internet connection.
• In PaaS, back end scalability is managed by the cloud
service provider, so end- users do not need to worry about
managing the infrastructure.
• PaaS includes infrastructure (servers, storage, and
networking) and platform (middleware, development tools,
database management systems, business intelligence, and
more) to support the web application life cycle.
• Example: Google App Engine, Force.com, Joyent, Azure.

Services provided by PAAS
1. Programming languages
PaaS providers provide various programming languages for the developers to
develop the applications. Some popular programming languages provided by
PaaS providers are Java, PHP, Ruby, Perl, and Go.
2. Application frameworks
PaaS providers provide application frameworks to easily understand the
application development. Some popular application frameworks provided by
PaaS providers are Node.js, Drupal, Joomla, WordPress, Spring, Play, Rack, and
Zend.
3. Databases
PaaS providers provide various databases such as
ClearDB, PostgreSQL, MongoDB, and
Redis to communicatewith the applications.
4. Other tools
PaaS providers provide various
other tools that are required to
develop, test, and deploy the
applications.

Advantages of PaaS
1) Simplified Development
PaaS allows developers to focus on development and innovation
without worrying about infrastructure management.
2) Lower risk
No need for up-front investment in hardware and software.
Developers only need a PC and an internet connection to start
building applications.
3) Prebuilt business functionality
Some PaaS vendors also provide already defined business
functionality so that users can avoid building everything from very
scratch and hence can directly start the projects only.
4) Instant community
PaaS vendors frequently provide online communities where the
developer can get the ideas to share experiences and seek advice
from others.
5) Scalability
Applications deployed can scale from one to thousands of users
without any changes to the applications.

PaaS Providers

Software as a Service | SaaS
• SaaS is also known as "On-Demand Software". It is a
software distribution model in which services are hosted by
a cloud service provider. These services are available to
end-users over the internet so, the end-users do not need
to install any software on their devices to access these
services.
There are the following services provided by SaaS providers
• Business Services - SaaS Provider provides various business
services to start-up the business. The SaaS business
services include ERP (Enterprise Resource
Planning), CRM (Customer Relationship
Management), billing, and sales.

Services provided by SaaS providers
• Document Management - SaaS document management is
a software application offered by a third party (SaaS
providers) to create, manage, and track electronic
documents.
Example: Slack, Samepage, Box, and Zoho Forms.
• Social Networks - As we all know, social networking sites
are used by the general public, so social networking service
providers use SaaS for their convenience and handle the
general public's information.
• Mail Services - To handle the unpredictable number of
users and load on e-mail services, many e-mail providers
offering their services using SaaS.

Services provided by SaaS providers

Advantages of SaaS cloud computing
layer
• 1) SaaS is easy to buy
• SaaS pricing is based on a monthly fee or annual fee subscription, so it
allows organizations to access business functionality at a low cost, which is
less than licensed applications.
• Unlike traditional software, which is sold as a licensed based with an up-
front cost (and often an optional ongoing support fee), SaaS providers are
generally pricing the applications using a subscription fee, mostcommonly
a monthly or annually fee.
• 2. One to Many
• SaaS services are offered as a one-to-many model means a single instance
of the application is shared by multiple users.
• 3. Less hardware requiredfor SaaS
• The software is hosted remotely, so organizations do not need to invest in
additional hardware.

Advantages of SaaS cloud computing layer
4. Low maintenance requiredfor SaaS
• Software as a service removes the need for installation, set-up, and daily
maintenance for the organizations. The initial set-up cost for SaaS is
typically less than the enterprise software. SaaS vendors are pricing their
applications based on some usage parameters, such as a number of users
using the application. So SaaS does easy to monitor and automatic
updates.
5. No special software or hardware versions required
• All users will have the same version of the software and typically access it
through the web browser. SaaS reduces IT support costs by outsourcing
hardware and software maintenance and support to the IaaS provider.
6. Multidevice support
• SaaS services can be accessed from any device such as desktops, laptops,
tablets, phones, and thin clients.
7. API Integration
• SaaS services easily integrate with other software or services through
standard APIs.
8. No client-side installation
• SaaS services are accessed directly from the service provider using the
internet connection, so do not need to require any software installation.

Multi Tenant Technology
• A multi-tenant cloud is a cloud computing architecture that allows
customers to share computing resources in a public or private
cloud. Each tenant's data is isolated and remains invisible to other
tenants.
• In a multi-tenant cloud system, users have individualized space for
storing their projects and data. Each section of a cloud network
with multi-tenant architecture includes complex permissions with
the intention of allowing each user access to only their stored
information along with security from other cloud tenants. Within
the cloud infrastructure, each tenant's data is inaccessible to all
other tenants, and can only be reached with the cloud provider's
permissions.
• In a private cloud, the customers, or tenants, may be different
individuals or groups within a single company, while in a public
cloud, entirely different organizations may safely share their server
space. Most public cloud providers use the multi-tenancy model. It
allows them to run servers with single instances, which is less
expensive and helps to streamline updates.

Multi-tenant cloud vs single-tenant
cloud
Multi-tenant cloud vs single-tenant cloud
• In a single-tenant cloud, only one customer is
hosted on a server and is granted access to it.
Due to multi-tenancy architectures hosting
multiples customers on the same servers, it is
important to fully understand the security and
performance the provider is offering. Single-
tenant clouds give customers more control over
the management of data, storage, security and
performance.

Multi-tenant cloud vs single-tenant
cloud

Benefits of multi-tenant cloud
• Multi-tenant cloud networks provide increased storage and
improved access compared to single-tenancy clouds that include
limited access and security parameters. Multi-tenancy in cloud
computing makes a greater pool of resources available to a larger
group of people without sacrificing privacy and security or slowing
down applications. The virtualization of storage locations in cloud
computing allows for flexibility and ease of access from almost any
device or location.
• Example of multi-tenancy
Multi-tenant clouds can be compared to the structure of an
apartment building. Each resident has access to their own
apartment within the agreement of the entire building and only
authorized individuals can enter the specific units. However, the
entire building shares resources such as water, electricity and
common areas.

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