Module 4

Models of Cloud Computing – Cloud Service Models – SaaS – PaaS – IaaS – Cloud
Deployment Models – Public, Private, Community and Hybrid Clouds – Cloud Storage

Cloud Data Centre – Cloud Data Centre Core Elements (Application, DBMS, Compute,
Storage and Network) – Storage Network Technologies – Cloud Backup – Cloud and
Disaster Recovery – Replication Technologies – Computing on Demand.
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Cloud Service Models

The cloud applications are built on three layers namely infrastructure, platform,software

Based on this there are 3 cloud computing models

 Iaas
 Paas
 Saas

Software as a Service
 Applications are hosted by a cloud vendor(supplier)
 This is available to the customers through the Internet
 The software is accessed at the customer’s location
 One machine can serve many cloud users simultaneously(multitenant)

Eg: Google Apps, Netflix, Gmail, Googlr Docs

Applications of SaaS

Complaint resolution system

Employee management system
Attendance management System

Importance of SaaS

 SaaS is one to many software delivery model

 Expenses is Nil
 Only a web browser is needed for accessing the service
 Very much scalable
 Applications are centrally managed.
 Data of every consumer is saved and protected
 Service level improvement
 Pay as you go pricing
 Rapid implementation

SaaS providers

NetSuite
Intuit
Financial Force.com
Coupa Software
AT &T

Platform as a Service

 Platform in computer software means Hardware architecture, OS, runtime libraries,

 All together it is the stage on which computer programs can be run
 PaaS gives all facilities needed for building and delivering a web application
 Cloud suppliers provide database, OS, web server and programming language.
 The application designers can build their application without purchasing the
software and hardware.

Eg: Google App Engine, Microsoft azure Mendix, Engine Yard

Importance of PaaS

 Cloud provides different platforms

 Multiple OS support
 Platform for accessing database
 Act as middleware

Uniqueness in PaaS

Application expansion: cloud user can customize the application as per requirement
Simplicity of use: user friendly . Drag and drop Integrated development environments
(IDE) are available.
Accessibility: an alternative platform is always available anywhere anytime
Scalability: the infrastructure can manage different application loads
Safety: only log on activities are provided
Comprehensiveness: application developed can be incorporated with other applications
Portability: applications can be shifted from one PaaS to another
Porting devices: for easy migration from on premise platform to online platform
Proper documentation: there is a properly documented API to document user
verification, recovery, savings of file etc.
Infrastructure as a service (IaaS)
 It is the delivery of computer infra structure as a service
 Cloud supplier provides computers as physical or virtual machines
 Virtual machines are operated by hypervisor (Xen, Vmware)
 Other IaaS resources are
 Image sin Virtual machine image history, blocks of storage, software collections,
firewalls, IP addresses, VLANs
 Cloud user deploy OS images on their application software and machine
 Cloud supplier prepare bill based on usage only.

Eg: Rackspace cloud, Amazon cloud formation, Google Compute Engine

IaaS providers

Amazon
Rackspace
Gogrid
Symetriq

Paas is dedicated to application developer.

Saas is for end user.
Iaas provides applications and middleware support to application developer.
Iaas is platform free.

It is an amalgamation of software and hardware resources.

Iaas software(hypervisor) runs independent of hardware. It keeps record of hardware
resource usage and distributes resources based on demand. This is called resource
pooling
Cloud Deployment Models

Private cloud:

 Cloud infrastructure is provided exclusively for a single organization with multiple

consumers.
 Owned , operated and managed by the organization or third party or combination
 It may exist on /off premises

Community cloud

 Cloud infrastructure is provided for exclusive use by specific community of

consumers within an organization( with similar mission, policy, security
requirements, )
 Owned managed and operated by one or more organizations in the community
 It may exist on /off premises

Public cloud

 This is for open use by general public

 May be owned, managed, operated by business academic or government
organization or a combination of them.
 It exists on the premises of the cloud provider

Hybrid cloud

 Composition of 2 or more distinct cloud infrastructure (private, community, or

public)
Public cloud

 Users have many options to opt for any service provider

 It may cost a lesser amount
 Private information of the cloud user is protected.
 The physical infrastructure is possessed by cloud service supplier
 The cloud consumers share the infra structure and pay for what they use.
 Different clients access collection of services provided by the cloud supplier

Eg: Google, Amazon Elastic Compute Cloud (EC3), Microsoft

Private cloud

 Private cloud services gives the control of cloud infra structure to the user
 Infrastructure access is permitted to members of organization
 Private cloud is hosted in the data centre of the company and services are offered to
users within the company
 Higher cost compared to public cloud
 A private cloud is possessed by the consumer, but constructed and deployed by a
third party
 Physical servers may be positioned at the location of the consumer
 Private clouds are owned by big organizations
 Safety is stricter in private cloud than in public cloud. Because the infrastructure is
owned by the organization and the organization has control over the applications
installed.

Eg: Vmware, Microsoft, Eucalyptus with Ubuntu Server

Virtual private cloud: a consumer is allotted private cloud inside public cloud’s
physical infrastructure

Community cloud
Limited and consumed by means of a group or cluster who are engaged in a general task.
The members of the society get access to the information on the cloud. Community cloud
falls between public and private cloud. Cost is higher than public cloud.
Eg: Google Gov Cloud, NASA Nebula cloud

Hybrid Cloud

 Hybrid cloud is a combination of two or more clouds, private, public and community
clouds
 Cloud users are supplied with information on the public cloud and the cloud supplier
has to maintain the company significant services.
 Hybrid cloud enables to migrate and manage workloads between these various cloud
environments
 organizations choose to adopt hybrid cloud platforms to reduce costs, minimize risk,
and extend their existing capabilities to support digital transformation.
 Cloud bursting is a configuration method that uses cloud computing resources
whenever on-premises infrastructure reaches peak capacity. When organizations run
out of computing resources in their internal data center, they burst the extra
workload to external third-party cloud services.

 Many organizations want to continue using their existing on-premises computing

infrastructure and also get the benefits of the public cloud.
 They can deploy a cloud-bursting hybrid cloud architecture to access public cloud
resources when they have no more on-premises compute capacity.

Advantages of cloud-bursting techniques

 Use local resources efficiently
 Reduce further investment in on-premises infrastructure costs
 Enjoy the scale and flexibility that public clouds bring
 Avoid service interruption to business-critical applications due to sudden workload
spikes

Cloud storage
 Cloud storage is a service model where in data is maintained, controlled, and backed
up distantly and made accessible to users over the Internet.
 It is a network of online storage hosted by third parties(cloud storage providers)
 Companies who need to host data, take storage space on rental basis
 Cloud storage is accessed through web based user interface or API

3 major cloud storage models

Public cloud storage(Amazon Simple Storage Service(S3)-multi occupant storage

Private cloud storage – dedicated storage restricted behind firewall of a corporation.

Suitable for users who need more customization and power on data.

Hybrid cloud storage- amalgamation of public and private cloud storage.

Storage Network Technologies
Cloud computing offers virtualization to provide services to more than one user at a
time.Communication is important between storage and virtualization devices.

Just-in-time information for business users.It is the information ought to be accessible to

users at the time they require it.
Cloud need a Resilient and flexible storage architecture .
Cloud uses Fibre channel storage area network (FC SAN) .
This is a high-pace, devoted network of systems and shared storage tools.
FC SAN employs small computer system interface (SCSI) protocol for transferring data
between storage tools and compute systems.

The following are the components of a Fibre Channel SAN:

 Node ports

 Cables Connectors

 Interconnecting devices

 Storage arrays

 SAN management software

The fibre channel fabric is a rational space wherein every joint converses with each other
via a switch or manifold unified FC switches.

Compute systems communicate with storage tools via specific vents known as ports.
Ports are the fundamental construction blocks of an FC network. In the network, ports
may be of different kinds as follows:

N_port - It is also called the node port. It is a compute system port host bus adaptor
(HBA) or a storage range port which is associated to a switch within a switched fibre.

E port - It is an FC port which develops the association between two FC switches. This
port is called the expansion port. The E port on an FC switch unites to the E port of other
FC switches in the network

F_port- It is a port on a switch which unites an N port. It is also defined as a fabric port.
G_port - It is a standard port which may function as an F port or an E port and decides
its functionality mechanically all through initialization.

World wide name and channel address are the two kinds of addresses which are used for
communication in an FC SAN situation.

Replication Technique
The procedure of generating an accurate/similar replica of data is known as replication.
The accurate copy of data that is generated is known as replica. Such replicas may be
used for revival in the occurrence of data loss.

The main aim of replication is to allow users to have the chosen data at the correct place,
in a condition suitable to the needs of revival.

This permits reviving industry functions by using the replicas.

1. Offering an alternating source for backup to enhance the effect on construction

2. Offering a source for rapid revival
3. Facilitating judgment support actions, like reporting
4. Mounting and analysing projected modification to an application or an operating
situation
5. Reviving an application from the copy in the occurrence of a malfunction in the source
level

Key Factors to Consider with Replicas

Replicas may be continuous replica or point-in-time (PIT).

Continuous replica: The data on the replica is matched with the manufacture data
during the entire period.

Point In Time: The data on the replica is a copied picture of the manufacture at a certain
timestamp.

Local replication is the procedure of replicating data inside a similar data center.

Local replication technologies may be categorized on the basis of the site where the
replication is carried out.

Compute-based : Replication is carried out using the resources of the CPU of the
computer system through software which is working on the compute system.

Compute-based regional replication may be more classified as file system snapshot and
logical volume management (LVM)- mirroring.

Storage array-based: Replication is carried out on the storage range by using the
resources of the CPU of the range via the operating environment of range.
Storage group-based regional replication may be classified follows:

 Pointer-based virtual replication

 Pointer-based complete degree replication
 Complete degree mirroring

Remote replication is the procedure of generating replicas of data to be kept in isolated

places for safety.

Remote replicas assist corporations to improve the threats associated with regionally
determined disaster.

The infrastructure where the replica is saved at the isolated location is called target. Data
has to be shifted from the source location to the target location over several networks.

The two fundamental manners of remote replications are a follows-synchronous and

asynchronous replication.

For improvement of threats recognized in two-site replication, three-site replication is

employed.

In a three-site replication, data from the source location is replicated to two remote
locations.

Replication might be synchronous or asynchronous.

Cloud backup
Backup is a replica of the manufactured data, generated and maintained for the only
intention of improving corrupted or deleted data.

Corporations require backup data at a cheaper price with the least number of resources.

Corporations should guarantee that true data is in the correct place at the correct time.

Backup technologies need a guarantee successful execution of the revival and backup
solution.

Backups are carried out for three key reasons-documentation, operational restores, and
disaster recovery.

The backup replicas are used for reinstating data at an alternate location when the
primary location is harmed because of a catastrophe.

Operational backup is a backup of data at a point in time and is used to reinstate data in
the occurrence of data loss or rational corruptions which can happen during routine
procedures.
Documentation is a general prerequisite used to protect contract report, email, and other
e work goods for rigid approval.

Full backup is a backup of the total data on the manufactured amounts at point in time
and is generated by replication of the data on the manufacture amounts to a secondary
storage tool. This is much quicker, but takes longer to reinstate.

Cumulative backup imitates data has been distorted since the last full backup. This
technique takes more time than incremental back up but is quicker to reinstate.

Synthetic full backup is another kind of backup which is employed in executions where
the construction amount resources cannot be entirely set aside for a backup procedure for
expanded phases.

A backup system uses client server design - backup server and multiple backup
consumers.

The backup server controls the backup function sustains the backup list that restrains
information regarding the backup metadata and backup procedure. The backup server
relies on the backup consumers for collecting the data to be backed up. The consumers
may be native to the server or may occupy an additional server, apparently to back data
perceptible to that server.

The backup metadata has been obtained by the backup server from the backup
consumers to out its actions. The metadata is saved either locally inside the backup
server or outwardly in a range. The storage joint is accountable for writing data to the
backup tool. Characteristically, the storage joint is incorporated through the backup
server and both are hosted on a similar physical platform. The storage node is directly
connected to a backup device.

Disaster recovery
The Backup Server commences the back up procedure for distinct customers according
to the back up program organized for them.The backup server synchronizes the backup
procedure with all the constituents in a backup arrangement. The backup server sustains
the information regarding the backup consumers to be dealt with and the storage joints to
be employed in a backup function. The backup server recovers the backup-concerned
information from the backup list and, on the basis of this information initiates a suitable
storage joint to put in the backup media into the backup tools.

Concurrently, it initiates the backup consumers to transmit their metadata to the backup
server to back up the data to a suitable storage joint. On getting this demand, the backup
consumer transmits trailing information to the backup server. The backup server
inscribes this metadata on its backup list.

The backup consumer transmits the data to the storage joint, and the storage joint
inscribes the data the storage tool. The storage joint transmits trailing information to the
backup server as well in order maintain it updated regarding the media being employed
in the backup procedure. A reinstate procedue is manually commenced by the backup
consumer. Upon getting a restore demand, the user unlock the reinstate application in
order to analyse the consumer's record which has been backed up. Whils choosing the
consumer for which a reinstate demand has been made, the user also requires recognizing
the consumer who will obtain the reinstated data. Data may be reinstated on a similar
consumer or another consumer, given the appropriate consents, and then the user chooses
the data which is to be reinstated.

The reinstated application should communicate with the backup server as well. The
backup server recognizes the backup media needed for the reinstate and informs the
storage joint to put in the backup media. Then, the data is interpreted and transmitted to
the consumer which has been recognized to obtain the reinstated data.

Tape drives, a low-priced alternative, is used for backup.

Data Centre Core elements

 Key component of cloud computing is virtualization
 Virtualization provides customized environment to different users
 It is sold on demand
 It is elastic
 Services is fully managed by the provider

The important cloud elements are

 Clients (mobile, thin or thick)

 Data centre (collection of ervers, IT, non IT requirements)
 Distributed Servers geographically distributed)
 storage

The principal components of a cloud data center (CDC) comprise:

Application: it is a computer program. It uses a DBMS to store , retrieve data

DBMS: it gives a systematic way to store and retrieve data in tables
Compute: it is a physical computing machine which controls applications, DBMS, and
OS
Storage : a tool to save data constantly. Storage requirement depends upon total data to
be saved and the time period for which the data is to be stored.
Network: it is a connecting path which allows communication among compute systems
and customers and among storage and compute systems

Application

Interface between host and user, or among multiple hosts.

Business applications have three layered design
application user interface- Front end layer
Application itself – middle layer
Database- back end layer
Data saved on server
Server replies to requests from user
Application transmits the requests to OS to carryout read write operations in the storage
media
R/W functions allow communication between front end and back end layer

Database Management Systems

A DBMS saves data in tables in an organized method

DBMS handles requests from application program, for data
It arranges incoming data in a customized way
Examples: SQL server, ORACLE, MySQL

Compute:

It consists of physical components (hardware devices) that communicate with one

another using software and protocols
Three main constituents
 Memory
 CPU
 Input Output tools
Also logical components ( softwares and protocols)

Types of communication
Between user and compute system (by I/O tools)
Between storage and compute system (by host bus adapter or host regulator )

Compute systems can be

 Separate servers / blade servers
A blade server, (a high-density server) is a compact device containing a computer used to
manage and distribute data in a collection of computers and systems. Its acts between
computers, programs, applications and systems.
Server grouping assembles two or more servers and make them to work collectively
It offers high accessibility and load balancing

 Plain laptops
 Processor
Storage

Data generated by companies or individuals should be saved so that it is effortlessly

available when required. Tools intended for saving data are known as storage tools or
merely storage. The sort of storage used differs on the basis of the kind of data and the
point at which it is generated and used. Tools like memory in a digital camera or cell
phone, CDROMs, DVDs, and disk drives in private computers illustrations of storage
tools. A storage tool utilizes optic, solid, or magnetic medium. DVD/CD utilizes optical
media, whereas diskettes, tapes, and disks use magnetic medium for storage.

Network

Protocol used for communication-

TCP/IP (for WAN , MAN)
Ethernet (LAN)
Every system has a NIC (Network interface card ) and MAC address
Routers and switches for interconnection
Compute storage communication is made possible through
Host bus adaptor (HBA)
Converged bus adaptor (CAN)