This document provides an architectural overview of cloud computing and describes how a payroll processing application could be migrated to the cloud. It discusses the key attributes and layers of cloud computing including infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS). It then describes how the existing payroll application, which is deployed on-premises at many government locations, could be re-architected as a multi-tenant SaaS application in the cloud to reduce costs and maintenance burdens.

1. Architectural Overview of
Cloud Computing
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2. Introduction
High performance networks and advanced
development of internet is the basis for cloud
computing .
Cloud computing has started taking shape
incorporating virtualization and on demand
deployment and internet delivery of services.
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3. Cloud is a pool of virtualized computer resources
networked, which can:
Host a variety of workloads.
Batch-style back-end jobs.
Interactive user-facing applications.
Workloads can be deployed and scaled out quickly through
the rapid provisioning of virtual machines or physical
machines.
Support redundant, self recovering, highly scalable
programming models that allow workloads to recover from
many unavoidable hardware / software failures.
Monitor resource use in real time to enable rebalancing of
allocations when needed.
Introduction
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4. Conventional
• Manually Provisioned
• Dedicated Hardware
• Fixed Capacity
• Pay for Capacity
• Capital & Operational
Expenses
Cloud
• Self-provisioned
• Shared Hardware
• Elastic Capacity
• Pay for Use
• Operational Expenses
Conventional Computing
vs.
Cloud Computing
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5. Five Key Cloud Attributes:
1. Shared / pooled resources
2. Broad network access
3. On-demand self-service
4. Scalable and elastic
5. Metered by use
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6. Shared / Pooled Resources:
• Resources are drawn from a common pool
• Common resources build economies of scale
• Common infrastructure runs at high efficiency
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7. Broad Network Access:
• Open standards and APIs
• Almost always IP, HTTP, and REST
• Available from anywhere with an internet
connection
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8. On-Demand Self-Service:
• Completely automated
• Users abstracted from the implementation
• Near real-time delivery (seconds or minutes)
• Services accessed through a self-serve
web interface
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9. Scalable and Elastic:
• Resources dynamically-allocated between
users
• Additional resources dynamically-released
when needed
• Fully automated
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10. Metered by Use:
• Services are metered, like a utility
• Users pay only for services used
• Services can be cancelled at any time
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11. Architecture Overview
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12. Architectural Layers of Cloud
Computing
In the cloud computing stack, there are three basic
layers that together create cloud environment. They
are:
1.Infrastructure as a Service(IaaS)
2.Platform as a Service (PaaS)
3.Software as a Service (SaaS)
SaaS
PaaS
I aaS
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13. SaaS
PaaS
IaaS
Amazon Google Microsoft Salesforce
Service Delivery Model
Examples
Products and companies shown for illustrative purposes only and should not
be construed as an endorsement 13Dr.K.Ashok kumar

14. Framework of cloud computing
Virtualized resources
Compute Networking
Storage
Image Metadata
Image
Virtualized images
Software kernel (OS. VM Manager)
Hardware
Application
Platform
Infrastructure
Basic middleware
(database services , application server )
Developments tools
Services and built in functionality
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15. Virtual infrastructure management
and Cloud Computing
For building the cloud environment a variety of
requirements must be met to provide a uniform and
homogeneous view of the virtualized resources.
Virtual Infrastructure Management is the key
component to build the cloud environment which does
the dynamic orchestration of virtual machines on a pool
of physical resources.
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16. Virtual infrastructure management provide primitives
to schedule and manage VMs across multiple physical
hosts.
Cloud management provide remote and secure
interface for creating controlling and monitoring
virtualized resources on IaaS.
Virtual infrastructure managementVirtual infrastructure management
and Cloud Computingand Cloud Computing
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17. View of Cloud Deployment
Cloud
Application
Client
Infrastructure
Application
PaaS
VirtualizedApplication
Platfor
m
Service
IaaS
Infrastructure
Storage
SaaS
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18. Software as a Service
 It is a Deployment/Delivery model
• Hosted and managed by vendor
• Delivered across the internet
 It is a Business Model : usage-based pricing(vs.
perpetual license model of on –premise
software).Examples:
• Per user per month
• Per transaction
• Per GB of storage per month
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19. Software as a ServiceSoftware as a Service
Architectural
 Multi-tenancy
 Scalability
 Security
 Performance
Functional
 Provisioning
 Billing
 Metering
 Monitoring
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20. MULTI-TENANCY
 Multi-tenancy is an architectural pattern
 A single instance of the software is run on the service
provider’s infrastructure
 Multiple tenants access the same instance.
 In contrast to the multi-user model, multi-tenancy
requires customizing the single instance according to
the multi-faceted requirements of many tenants.
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21. A Multi-tenants application lets customers (tenants) share the
same hardware resources, by offering them one shared
application and database instance ,while allowing them to
configure the application to fit there needs as if it runs on
dedicated environment.
These definition focus on what we believe to be the key
aspects of multi tenancy:
1.The ability of the application to share hardware resources.
2.The offering of a high degree of configurability of the
software.
3.The architectural approach in which the tenants make use
of a single application and database instance.
MULTI-TENANCYMULTI-TENANCY
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22. Multi-tenants Deployment Modes
for Application Server
Tenant A
Fully isolated Application server
Each tenant accesses an application
server running on a dedicated servers.
Virtualized Application Server
Each tenant accesses a dedicated
application running on a separate virtual
machine.
Shared Virtual Server
Each tenant accesses a dedicated
application server running on a shared
virtual machine.
Shared Application Server
The tenant shared the application server
and access application resources
through separate session or threads.
Tenant B
Application Server
Application server
Virtual
machine
Virtual
machine
Application server
Tenant A
Tenant B
Virtual
machine
Tenant A
Tenant B
Session thread
Session Thread
Application Server
Tenant A
Tenant B
Application server
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23. Multi-tenants Deployment Modes in Data Centers
Fully isolated data center
The tenants do not share any data
center resources
Virtualized servers
The tenants share the same host but
access different databases running
on separate virtual machines
Shared Server
The tenants share the same server
(Hostname or IP) but access
different databases
Shared Database
The tenants share the same server
and database (shared or different
ports) but access different
schema(tables)
Shared Schema
The tenants share the same server,
database and schema (tables). The
irrespective data is segregated by
key and rows.
Tenant A
Tenant B
Tenant A
Tenant B
Tenant A
Tenant B
Virtual
Machine Database
Virtual
Machine
Database
Tenant A
Tenant B
Tenant A
Tenant B
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24. Conceptual framework of Software as a Service
Presentation Menu and Navigation User Controls Display and Rendering Reporting
Security
Identity and
federation
Authentication and
Single Sign on
Authorization and
Role-based Access
Control
Entitlement
Encryption
Regularity Controls
Operation
Monitoring and
Altering
Backup and Restore
Provisioning
Configuration and
Customization
Performance and
Availability
Metering and Indicators
Infrastructure
Database Storage Computer Networking and
Communications
Application Engine
User Profile
Notification and
Subscription
Metadata
Execution
Engine
Metadata
Services
Messaging
Workflow
Execution
Handling
Orchestration
Data
Synchronization
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25. Migrating to Cloud Environment
The Software can be redeployed in cloud
environment as Software as a Service (SaaS).
The main sections of the software can be
mapped to the SaaS architecture.
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26. Payroll Processing in Cloud
Computing
Many State Government departments are utilizing
standardized set up of payroll packages which are
deployed at user locations and it is amounting huge
investment on procurement of hardware and software
and maintenance for various locations of the
organization.
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27. Payroll Software Installed at more thanPayroll Software Installed at more than
300 locations300 locations
User Software Module
Standalone Loaded on PC
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28. DrawbacksDrawbacks
Drawbacks :
 Software Maintenance problems.
 Individual Hardware is required.
 Often Data Loss occurs.
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29. Migrating the payroll package, to cloud
environment can be worked out without
changing business logic.
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30. IN CLOUD
User-1
Software
Module
User-1 User-3
Single Instance
Multi-tenancy
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31. Architectural Overview for Multi-tenancy
Client
Authentication
Authentication
Module
Ticket Server
Session Ticket
Tenant Token
+ Create Ticket()
Tenant Auth
Data
Tenant
Config
Data
Layout Component
Configuration Component
File I/O Component
Workflow Component
Database
Query Adjuster Load Balancer Record Initializer
Database Pool
Data Data Data
Single-tenant
business logic
Query
Create Ticket()
HTTP
Request
Configuration
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32. Provisioning for new tenants
• For Separate server model new machine is to be
installed.
• For separate database model create a database
start it on a server.
• For separate schema and shared schema models
scripts / stored procedure could create new
schema in one of the existing databases.
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33. Background of the Application
The existing application, which is implemented in state
government departments, is having the following main
sections:
 Data admin
 Master data entry
 Month process
 Token no. entry
 Reports
 Back up to system
The existing package is deployed in the user premises and
found difficult in regular software maintenance and
overhead costs for the infrastructure requirements.
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34. The application is ideally suited to deploy in cloud
environment with following features:
 The application can be taken up as a single instance and multi-
tenant model
 Configurability option in the software is required to be provided.
Configurability in SaaS enables the flexibility to access the software
by many tenants with the option of configuring each tenant for
their application needs.
 The software will have configurability for the following :
1.User interface.
2.Workflow.
3.Data.
4.Access control.
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35. User requirements / Use cases Type of environment in cloud Impact
Payroll processing IaaS (VM)
Cloud storage and
SaaS
1. Processing time will be reduced.
2. Hardware requirements will be
reduced.
3. Number of users can be
increased with scalability.
4. Maintenance cost will be
reduced.
Project Management PaaS and Cloud storage 1. Processing time can be reduced.
2. Project execution time and cost
can be reduced.
3. Efficient way of utilization of skill
sets and manpower can be attained.
e-Governance & Office automation IaaS
Cloud storage
SaaS
1. Hardware cost can be reduced.
2. CPU processing time can be
reduced.
3. Accountability can be maintained.
4. Maintainance cost can be
reduced.
5. Reduces energy consumption.
SaaS ApplicationsSaaS Applications
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36. SOA and Cloud Computing
In cloud environment we adopt the bundling of resources into
layers of
Saas
Paas
Iaas
And furthur add a layer for business process management with
the concept of service oriented architecture(SOA).
SOA is a base for furthur building of cloud environment for
composite application with work flow concepts.
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