UNIT-3

LAYERED CLOUD ARCHITECTURE DESIGN-

Layered Architecture of Cloud

Application Layer

1. The application layer, which is at the top of the stack, is where the actual cloud apps are located. Cloud applications,
as opposed to traditional applications, can take advantage of the automatic-scaling functionality to gain greater
performance, availability, and lower operational costs.
2. This layer consists of different Cloud Services which are used by cloud users. Users can access these applications
according to their needs. Applications are divided into Execution layers and Application layers.
3. In order for an application to transfer data, the application layer determines whether communication partners are
available. Whether enough cloud resources are accessible for the required communication is decided at the
application layer. Applications must cooperate in order to communicate, and an application layer is in charge of this.
4. The application layer, in particular, is responsible for processing IP traffic handling protocols like Telnet and FTP.
Other examples of application layer systems include web browsers, SNMP protocols, HTTP protocols, or HTTPS,
which is HTTP’s successor protocol.
Platform Layer
1. The operating system and application software make up this layer.
2. Users should be able to rely on the platform to provide them with Scalability, Dependability, and Security
Protection which gives users a space to create their apps, test operational processes, and keep track of execution
outcomes and performance. SaaS application implementation’s application layer foundation.
3. The objective of this layer is to deploy applications directly on virtual machines.
4. Operating systems and application frameworks make up the platform layer, which is built on top of the infrastructure
layer. The platform layer’s goal is to lessen the difficulty of deploying programmers directly into VM containers.
5. By way of illustration, Google App Engine functions at the platform layer to provide API support for implementing
storage, databases, and business logic of ordinary web apps.
Infrastructure Layer

1. It is a layer of virtualization where physical resources are divided into a collection of virtual resources using
virtualization technologies like Xen, KVM, and VMware.
2. This layer serves as the Central Hub of the Cloud Environment, where resources are constantly added utilizing a
variety of virtualization techniques.
3. A base upon which to create the platform layer. constructed using the virtualized network, storage, and computing
resources. Give users the flexibility they want.
4. Automated resource provisioning is made possible by virtualization, which also improves infrastructure
management.
5. The infrastructure layer sometimes referred to as the virtualization layer, partitions the physical resources using
virtualization technologies like Xen, KVM, Hyper-V, and VMware to create a pool of compute and storage
resources.
6. The infrastructure layer is crucial to cloud computing since virtualization technologies are the only ones that can
provide many vital capabilities, like dynamic resource assignment.

Datacenter Layer

 In a cloud environment, this layer is responsible for Managing Physical Resources such as servers, switches,
routers, power supplies, and cooling systems.
 Providing end users with services requires all resources to be available and managed in data centers.
 Physical servers connect through high-speed devices such as routers and switches to the data center.
 In software application designs, the division of business logic from the persistent data it manipulates is well-
established. This is due to the fact that the same data cannot be incorporated into a single application because it can
be used in numerous ways to support numerous use cases. The requirement for this data to become a service has
arisen with the introduction of microservices.
 A single database used by many micro services creates a very close coupling. As a result, it is hard to deploy new or
emerging services separately if such services need database modifications that may have an impact on other services.
A data layer containing many databases, each serving a single micro service or perhaps a few closely related micro
services, is needed to break complex service interdependencies.

NIST CLOUD COMPUTING REFERENCE ARCHITECTURE

The NIST cloud computing definition [1] is widely accepted as a valuable contribution toward providing a clear
understanding of cloud computing technologies and cloud services. It provides a simple and unambiguous taxonomy of
three service models available to cloud consumers: cloud software as a service (SaaS), cloud platform as a service
(PaaS), and cloud infrastructure as a service (IaaS). It also summarizes four deployment models describing how the
computing infrastructure that delivers these services can be shared: private cloud, community cloud, public cloud, and
hybrid cloud. Finally, the NIST definition also provides a unifying view of five essential characteristics that all cloud
services exhibit: on demand self-service, broad network access, resource pooling, rapid elasticity, and measured service.
The Conceptual Reference Model Figure presents an overview of the NIST cloud computing reference architecture,
which identifies the major actors, their activities and functions in cloud computing. The diagram depicts a generic high-
level architecture and is intended to facilitate the understanding of the requirements, uses, characteristics and standards
of cloud computing. Figure 1: The Conceptual Reference Model As shown in Figure 1, the NIST cloud computing
 reference architecture defines five major actors: cloud consumer, cloud provider, cloud carrier, cloud auditor and cloud
broker. Each actor is an entity (a person or an organization) that participates in a transaction or process and/or performs
tasks in cloud computing. Table briefly lists the actors defined in the NIST cloud computing reference architecture.

ACTOR DEFINITION
Cloud Consumer A person or organization that maintains a business relationship with, and uses service
from, Cloud Providers.
Cloud Provide A person, organization, or entity responsible for making a service available to interested
parties.
Cloud Auditor A party that can conduct independent assessment of cloud services, information system
operations, performance and security of the cloud implementation.
Cloud Broker An entity that manages the use, performance and delivery of cloud services, and
negotiates relationships between Cloud Providers and Cloud Consumers.
Cloud Carrier An intermediary that provides connectivity and transport of cloud services from Cloud
Providers to Cloud Consumers.

Cloud Consumer -The cloud consumer is the principal stakeholder for the cloud computing service. A cloud consumer
represents a person or organization that maintains a business relationship with, and uses the service from a cloud provider.
A cloud consumer browses the service catalog from a cloud provider, requests the appropriate service, sets up service
contracts with the cloud provider, and uses the service. The cloud consumer may be billed for the service provisioned, and
needs to arrange payments accordingly. Cloud consumers need SLAs to specify the technical performance requirements
fulfilled by a cloud provider. SLAs can cover terms regarding the quality of service, security, remedies for performance
failures. A cloud provider may also list in the SLAs a set of promises explicitly not made to consumers, i.e. limitations, and
obligations that cloud consumers must accept. A cloud consumer can freely choose a cloud provider with better pricing and
more favorable terms. Typically a cloud provider‟s pricing policy and SLAs are non-negotiable, unless the customer
expects heavy usage and might be able to negotiate for better contracts. Depending on the services requested, the activities
and usage scenarios can be different among cloud consumers. Figure 6 presents some example cloud services available to a
cloud consumer (For details, see Appendix B: Examples of Cloud Services) [13]. NIST SP 500-292 NIST Cloud Computing
Reference Architecture 6 Figure 6: Example Services Available to a Cloud Consumer SaaS applications in the cloud and
made accessible via a network to the SaaS consumers. The consumers of SaaS can be organizations that provide their
members with access to software applications, end users who directly use software applications, or software application
administrators who configure applications for end users. SaaS consumers can be billed based on the number of end users,
the time of use, the network bandwidth consumed, the amount of data stored or duration of stored data. Cloud consumers of
PaaS can employ the tools and execution resources provided by cloud providers to develop, test, deploy and manage the
applications hosted in a cloud environment. PaaS consumers can be application developers who design and implement
application software, application testers who run and test applications in cloud-based environments, application deployers
who publish applications into the cloud, and application administrators who configure and monitor application performance
on a platform. PaaS consumers can be billed according to, processing, database storage and network resources consumed by
the PaaS application, and the duration of the platform usage. Consumers of IaaS have access to virtual computers, network-
accessible storage, network infrastructure components, and other fundamental computing resources on which they can
deploy and run arbitrary software. The consumers of IaaS can be system developers, system administrators and IT managers
who are interested in creating, installing, managing and monitoring services for IT infrastructure operations. IaaS consumers
are provisioned with the capabilities to access these computing resources, and are billed according to the amount or duration
of the resources consumed, such as CPU hours used by virtual computers, volume and duration of data stored, network
bandwidth consumed, number of IP addresses used for certain intervals. NIST Cloud Computing Reference Architecture
Cloud Provider- A cloud provider is a person, an organization; it is the entity responsible for making a service available to
interested parties. A Cloud Provider acquires and manages the computing infrastructure required for providing the services,
runs the cloud software that provides the services, and makes arrangement to deliver the cloud services to the Cloud
Consumers through network access. For Software as a Service, the cloud provider deploys, configures, maintains and
updates the operation of the software applications on a cloud infrastructure so that the services are provisioned at the
expected service levels to cloud consumers. The provider of SaaS assumes most of the responsibilities in managing and
controlling the applications and the infrastructure, while the cloud consumers have limited administrative control of the
applications. For PaaS, the Cloud Provider manages the computing infrastructure for the platform and runs the cloud
software that provides the components of the platform, such as runtime software execution stack, databases, and other
middleware components. The PaaS Cloud Provider typically also supports the development, deployment and management
process of the PaaS Cloud Consumer by providing tools such as integrated development environments (IDEs), development
version of cloud software, software development kits (SDKs), deployment and management tools. The PaaS Cloud
Consumer has control over the applications and possibly some the hosting environment settings, but has no or limited
access to the infrastructure underlying the platform such as network, servers, operating systems (OS), or storage. For IaaS,
the Cloud Provider acquires the physical computing resources underlying the service, including the servers, networks,
storage and hosting infrastructure. The Cloud Provider runs the cloud software necessary to makes computing resources
available to the IaaS Cloud Consumer through a set of service interfaces and computing resource abstractions, such as
virtual machines and virtual network interfaces. The IaaS Cloud Consumer in turn uses these computing resources, such as a
virtual computer, for their fundamental computing needs Compared to SaaS and PaaS Cloud Consumers, an IaaS Cloud
Consumer has access to more fundamental forms of computing resources and thus has more control over the more software
components in an application stack, including the OS and network. The IaaS Cloud Provider, on the other hand, has control
over the physical hardware and cloud software that makes the provisioning of these infrastructure services possible, for
example, the physical servers, network equipments, storage devices, host OS and hypervisors for virtualization. A Cloud
Provider‟s activities can be described in five major areas, as shown in Figure 7, a cloud provider conducts its activities in
the areas of service deployment, service orchestration, cloud service management, security, and privacy.

Cloud Auditor- A cloud auditor is a party that can perform an independent examination of cloud service controls with the
intent to express an opinion thereon. Audits are performed to verify conformance to standards through review of objective
evidence. A cloud auditor can evaluate the services provided by a cloud provider in terms of security controls, privacy
impact, performance, etc. Auditing is especially important for federal agencies as “agencies should include a contractual
clause enabling third parties to assess security controls of cloud providers” . Security controls are the management,
operational, and technical safeguards or countermeasures employed within an organizational information system to protect
the confidentiality, integrity, and availability of the system and its information. For security auditing, a cloud auditor can
make an assessment of the security controls in the information system to determine the extent to which the controls are
implemented correctly, operating as intended, and producing the desired outcome with respect to the security requirements
for the system. The security auditing should also include the verification of the compliance with regulation and security
policy. For example, an auditor can be tasked with ensuring that the correct policies are applied to data retention according
to relevant rules for the jurisdiction. The auditor may ensure that fixed content has not been modified and that the legal and
business data archival requirements have been satisfied. A privacy impact audit can help Federal agencies comply with
applicable privacy laws and regulations governing an individual’s privacy, and to ensure confidentiality, integrity, and
availability of an individuals personal information at every stage of development and operation . 2.5 Cloud Broker As cloud
computing evolves, the integration of cloud services can be too complex for cloud consumers to manage. A cloud consumer
may request cloud services from a cloud broker, instead of contacting a cloud provider directly. A cloud broker is an entity
that manages the use, performance and delivery of cloud services and negotiates relationships between cloud providers and
cloud consumers. In general, a cloud broker can provide services in three categories : Service Intermediation: A cloud
broker enhances a given service by improving some specific capability and providing value-added services to cloud
consumers. The improvement can be managing access to cloud services, identity management, performance reporting,
enhanced security, etc. Service Aggregation: A cloud broker combines and integrates multiple services into one or more
new services. The broker provides data integration and ensures the secure data movement between the cloud consumer and
multiple cloud providers. Service Arbitrage: Service arbitrage is similar to service aggregation except that the services being
aggregated are not fixed. Service arbitrage means a broker has the flexibility to choose services from multiple agencies. The
cloud broker, for example, can use a credit-scoring service to measure and select an agency with the best score. 2.6 Cloud
Carrier A cloud carrier acts as an intermediary that provides connectivity and transport of cloud services between cloud
consumers and cloud providers. Cloud carriers provide access to consumers through network, telecommunication and other
access devices. For example, cloud consumers can obtain cloud services NIST SP 500-292 NIST Cloud Computing
Reference Architecture 9 through network access devices, such as computers, laptops, mobile phones, mobile Internet
devices (MIDs), etc [1]. The distribution of cloud services is normally provided by network and telecommunication carriers
or a transport agent [8], where a transport agent refers to a business organization that provides physical transport of storage
media such as high-capacity hard drives. Note that a cloud provider will set up SLAs with a cloud carrier to provide services
consistent with the level of SLAs offered to cloud consumers, and may require the cloud carrier to provide dedicated and
secure connections between cloud consumers and cloud providers. 2.7 Scope of Control between Provider and Consumer
The Cloud Provider and Cloud Consumer share the control of resources in a cloud system. As illustrated in Figure 8,
different service models affect an organization’s control over the computational resources and thus what can be done in a
cloud system. The figure shows these differences using a classic software stack notation comprised of the application,
middleware, and OS layers.

Public Cloud vs Private Cloud vs Hybrid Cloud

Public Cloud
A Public Cloud is Cloud Computing in which the infrastructure and services are owned and operated by a third-party
provider and made available to the public over the internet. The public can access and use shared resources, such as
servers, storage, and applications and the main thing is you pay for what you used. . Examples of public cloud providers
– are Amazon Web Services (AWS), Microsoft Azure, and Google Cloud Platform (GCP)

Advantages

 Cost Efficient: In the public cloud, we have to pay for what we used. So it is more cost-efficient than maintaining
the physical servers or their own infrastructure.
 Automatic Software Updates: In the public cloud, there are automatic software updates. we don’t have to update
the software manually.
 Accessibility: Public clouds allow users to access their resources and applications from anywhere in the world. We
just need an internet connection to access it.

Disadvantages

 Security and Privacy Concerns: Public clouds can be vulnerable to data breaches, cyber attacks, and other security
risks. Since data is stored on servers owned by a third-party provider, there is always a risk that confidential or
sensitive data may be exposed or compromised.
 Limited Control: With public cloud services, users have limited control over the infrastructure and resources used
to run their applications. This can make it difficult to customize the environment to meet specific requirements.
 Reliance on Internet Connectivity: Public cloud services require a reliable and stable internet connection to access
the resources and applications hosted in the cloud. If the internet connection is slow or unstable, it can affect the
performance and availability of the services.
 Service Downtime: Public cloud providers may experience service downtime due to hardware failures, software
issues, or maintenance activities. This can result in temporary loss of access to applications and data.
 Compliance and Regulatory Issues: Public cloud services may not meet certain compliance or regulatory
requirements, such as those related to data privacy or security. This can create legal or contractual issues for
businesses that are subject to these requirements.
 Cost Overruns: Public cloud services are typically billed on a pay-per-use basis, which can result in unexpected
cost overruns if usage exceeds anticipated levels. Additionally, the cost of using public cloud services may increase
over time, as providers adjust their pricing models or add new features and services.
Private Cloud
A Private Cloud is a cloud computing environment in which the infrastructure and services are owned and operated by a
single organization, for example, a company or government, and it is accessed by only authorized users within that
organization. Private Cloud organizations have their own data center. private cloud provides a higher level of security.
Examples – HPE, Dell, VMware, etc.

Advantages

 Security Status: Private clouds provide a higher level of security. as the organization has full control over the cloud
service. They can customize the servers to manage their security.
 Customization of Service: Private clouds allow organizations to customize the infrastructure and services to meet
their specific requirements. and also can customize the security.
 Privacy: Private clouds provide increased privacy as the organization(company or government ) has more control
over who has access to their data and resources.

Disadvantages

 Higher Cost: Private clouds require dedicated hardware, software, and networking infrastructure, which can be
expensive to acquire and maintain. This can make it challenging for smaller businesses or organizations with limited
budgets to implement a private cloud.
 Limited Scalability: Private clouds are designed to serve a specific organization, which means that they may not be
as scalable as public cloud services. This can make it difficult to quickly add or remove resources in response to
changes in demand.
 Technical Complexity: Setting up and managing a private cloud infrastructure requires technical expertise and
specialized skills. This can be a challenge for organizations that lack in-house IT resources or expertise.
 Security Risks: Private clouds are typically considered more secure than public clouds since they are operated
within an organization’s own infrastructure. However, they can still be vulnerable to security risks such as data
breaches or cyber attacks.
 Lack of Standardization: Private clouds are often built using proprietary hardware and software, which can make it
challenging to integrate with other cloud services or migrate to a different cloud provider in the future.
 Maintenance and Upgrades: Maintaining and upgrading a private cloud infrastructure can be time-consuming and
resource-intensive. This can be a challenge for organizations that need to focus on other core business activities.
Hybrid Cloud
A hybrid cloud is a combination of both public and private cloud environments that allows organizations to take
advantage of the benefits of both types of clouds. It manages traffic levels during peak usage periods It can provide
greater flexibility, scalability, and cost-effectiveness than using a single cloud environment. Examples – IBM, DataCore
Software, Rackspace, Threat Stack, Infinidat, etc.

Advantages

 Flexibility: Hybrid cloud stores its data (also sensitive) in a private cloud server. While public server provides
Flexibility and Scalability.
 Scalability: Hybrid cloud Enables organizations to move workloads back and forth between their private and public
clouds depending on their needs.
 Security: Hybrid cloud controls over highly sensitive data. and it provides high-level security. Also, it takes
advantage of the public cloud’s cost savings.

Disadvantages

 Complexity: Hybrid clouds are complex to set up and manage since they require integration between different cloud
environments. This can require specialized technical expertise and resources.
 Cost: Hybrid clouds can be more expensive to implement and manage than either public or private clouds alone, due
to the need for additional hardware, software, and networking infrastructure.
 Security Risks: Hybrid clouds are vulnerable to security risks such as data breaches or cyber attacks, particularly
when there is a lack of standardization and consistency between the different cloud environments.
 Data Governance: Managing data across different cloud environments can be challenging, particularly when it
comes to ensuring compliance with regulations such as GDPR or HIPAA.
 Network Latency: Hybrid clouds rely on communication between different cloud environments, which can result in
network latency and performance issues.
 Integration Challenges: Integrating different cloud environments can be challenging, particularly when it comes to
ensuring compatibility between different applications and services.
 Vendor Lock-In: Hybrid clouds may require organizations to work with multiple cloud providers, which can result
in vendor lock-in and limit the ability to switch providers in the future.
Difference between Public Cloud vs Private Cloud vs Hybrid Cloud
Factors Public Cloud Private Cloud Hybrid Cloud

Resources are shared Resources are shared

It is a combination of public and private clouds.
Resources among multiple with a single
based on the requirement.
customers organization

Data of multiple Data of a single

Data is stored in the public cloud, and provide
Tenancy organizations is stored organization is stored in
security in the public cloud.
in the public cloud a clouds the public cloud

Pay Model Pay what you used Have a variety of pricing It can include a mix of public cloud pay-as-you-
models go pricing, and private cloud fixed pricing. It
has other pricing models such as consumption-
based, subscription-based, etc.
 Third-party service
Operated by Specific organization Can be a combination of both
provider

It has scalability and flexibility by allowing

Scalability and It has more scalability It has predictability and
organizations to use a combination of public and
Flexibility and flexibility, consistency
private cloud services.

Can be more expensive, but it can also be less

Expensive less expensive More expensive expensive , depending on the specific needs and
requirements of the organization.

The general public Restricted to a specific

Availability Can be a combination of both.
(over the internet) organization
Infrastructure as a Service | IaaS
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.

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.

IaaS is offered in three models: public, private, and hybrid cloud. The private cloud implies that the infrastructure resides at
the customer-premise. In the case of public cloud, it is located at the cloud computing platform vendor's data center, and the
hybrid cloud is a combination of the two in which the customer selects the best of both public cloud or private cloud.

IaaS provider provides the following services -

1. Compute: Computing as a Service includes virtual central processing units and virtual main
memory for the Vms that is provisioned to the end- users.
2. Storage: IaaS provider provides back-end storage for storing files.
3. Network: Network as a Service (NaaS) provides networking components such as routers,
switches, and bridges for the Vms.
4. 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.

Disadvantages of IaaS cloud computing layer

1. Security

Security is one of the biggest issues in IaaS. Most of the IaaS providers are not able to provide 100%
security.

2. Maintenance & Upgrade

Although IaaS service providers maintain the software, but they do not upgrade the software for some
organizations.

3. Interoperability issues
It is difficult to migrate VM from one IaaS provider to the other, so the customers might face problem
related to vendor lock-in.

Some important point about IaaS cloud computing layer

IaaS cloud computing platform cannot replace the traditional hosting method, but it provides more than
that, and each resource which are used are predictable as per the usage.

IaaS cloud computing platform may not eliminate the need for an in-house IT department. It will be
needed to monitor or control the IaaS setup. IT salary expenditure might not reduce significantly, but
other IT expenses can be reduced.

Breakdowns at the IaaS cloud computing platform vendor's can bring your business to the halt stage.
Assess the IaaS cloud computing platform vendor's stability and finances. Make sure that SLAs (i.e.,
Service Level Agreement) provide backups for data, hardware, network, and application failures. Image
portability and third-party support is a plus point.

The IaaS cloud computing platform vendor can get access to your sensitive data. So, engage with
credible companies or organizations. Study their security policies and precautions.

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.

PaaS providers provide the Programming languages, Application frameworks, Databases, and Other tools:
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
communicate with the applications.

4. Other tools
PaaS providers provide various other tools that are required to develop, test, and deploy the
applications.

Advantages of PaaS
There are the following 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.

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.

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.

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, most commonly 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 required for SaaS

The software is hosted remotely, so organizations do not need to invest in additional hardware.

4. Low maintenance required for 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.

Disadvantages of SaaS cloud computing layer

1) Security

Actually, data is stored in the cloud, so security may be an issue for some users. However, cloud
computing is not more secure than in-house deployment.

2) Latency issue

Since data and applications are stored in the cloud at a variable distance from the end-user, there is a
possibility that there may be greater latency when interacting with the application compared to local
deployment. Therefore, the SaaS model is not suitable for applications whose demand response time
is in milliseconds.

3) Total Dependency on Internet

Without an internet connection, most SaaS applications are not usable.

4) Switching between SaaS vendors is difficult

Switching SaaS vendors involves the difficult and slow task of transferring the very large data files over
the internet and then converting and importing them into another SaaS also.

Popular SaaS Providers

ARCHITECTURAL DESIGN CHALLENGES

1. Data Security and Privacy

Data security is a major concern when switching to cloud computing. User or organizational
data stored in the cloud is critical and private. Even if the cloud service provider assures data
integrity, it is your responsibility to carry out user authentication and authorization, identity
management, data encryption, and access control. Security issues on the cloud include
identity theft, data breaches, malware infections, and a lot more which eventually decrease
the trust amongst the users of your applications

2. Cost Management

Even as almost all cloud service providers have a “Pay As You Go” model, which reduces the
overall cost of the resources being used, there are times when there are huge costs incurred
to the enterprise using cloud computing. When there is under optimization of the resources,
let’s say that the servers are not being used to their full potential, add up to the hidden costs.

3. Multi-Cloud Environments

Due to an increase in the options available to the companies, enterprises not only use a
single cloud but depend on multiple cloud service providers. Most of these companies use
hybrid cloud tactics and close to 84% are dependent on multiple clouds. This often ends up
being hindered and difficult to manage for the infrastructure team. The process most of the
time ends up being highly complex for the IT team due to the differences between multiple
cloud providers.

4. Performance Challenges
Performance is an important factor while considering cloud-based solutions. If the
performance of the cloud is not satisfactory, it can drive away users and decrease profits.
Even a little latency while loading an app or a web page can result in a huge drop in the
percentage of users.

5. Interoperability and Flexibility

When an organization uses a specific cloud service provider and wants to switch to another
cloud-based solution, it often turns up to be a tedious procedure since applications written for
one cloud with the application stack are required to be re-written for the other cloud.

6. High Dependence on Network

Since cloud computing deals with provisioning resources in real-time, it deals with enormous
amounts of data transfer to and from the servers. This is only made possible due to the
availability of the high-speed network.

7. Lack of Knowledge and Expertise

Due to the complex nature and the high demand for research working with the cloud often
ends up being a highly tedious task. It requires immense knowledge and wide expertise on
the subject. Although there are a lot of professionals in the field they need to constantly
update themselves. Cloud computing is a highly paid job due to the extensive gap between
demand and supply.

Cloud Storage
The cloud storage is a computer data storage model in which the data that is digital in format is
stored, and hence it is said to be on the cloud, in logical pools. This physical storage consists of
multiple servers which can be located in the different parts of the country or may be in different parts
of the world depends on many factors. The maintenance of these servers is owned by some private
companies.

The cloud storage services are also responsible for keeping the data available and accessible 24x7,
and it also safeguard the data and run the physical environment. In order to store user, entity, or
application information, individuals and organisations purchase or lease storage capacity from
providers.

The Cloud storage resources, for example a cloud desktop storage, a cloud storage portal or a
Network-based content management system in the cloud. These all can be easily accessed with the
help of a co-located cloud computing service or it can be a web service application programming
interface which in general is known by the name of API or applications that use the API.

Architecture of Cloud Storage

In terms of interfaces the cloud storage is basically based on highly virtualized technology which is
more like broader cloud computing. It is possible to use cloud storage services from an off-site
provider (Amazon S3) or from an on-site provider (ViON Capacity Services).

Usually, cloud storage refers to a hosted object storage service, although the concept has extended
to include other forms of data storage, such as block storage, that are also available as a service.

Some of the examples of cloud storage which can easily be hosted and deployed with cloud storage
characteristics are as follows -, Oracle Cloud Storage, Microsoft Azure Storage and Amazon S3.

Cloud storage is

o It consists of several distributed resources, but still functions as one, either in a cloud
architecture of federated or cooperative storage.
o Highly fault-tolerant via redundancy and data distribution.
o Extremely durable through the manufacture of copies of versions.
o Ultimately, it is usually compatible with data replication advantages.
o Companies just need to pay for the storage they actually use, normally an average of a month's
consumption. This does not indicate that cloud storage is less costly, rather that operating costs
are incurred rather than capital expenses.
o Cloud storage companies can cut their energy usage by up to 70 percent, making them a
greener company.
o The provision of storage and data security is inherent in the architecture of object storage, so the
additional infrastructure, effort and expense to incorporate accessibility and security can be
removed depending on the application.
o 10 Advantages of Cloud Storage
o Below are the advantages of cloud storage:
o 1. Cost Saving
o By using cloud storage, there is no need to buy as many hard drives, enclosures to
house them in, RAID cards to enable data redundancy, electricity to power them, or
hardware warranty services to safeguard them. However, it also cuts management
expenses by decreasing the need for in-depth capacity planning, streamlining
monitoring, and minimizing on-premise hardware and software management.
Administrators can instead concentrate on other, more crucial activities.
o 2. Data Redundancy and Replication
o The majority of cloud storage providers maintain numerous copies of data, even inside of
a single “Data Center”, and they provide excellent object durability to lower the risk of
data loss. Geographic replication options, however, can spread out several copies of
data across areas if you’re searching for even greater security. Others provide
replication services that swiftly transfer data between data centers, while some offer
geo-replication as a storage class option. Your backups are adequately shielded.
o 3. Data Tiering for Cost Savings
o Various storage classes and data tiers are offered by numerous cloud storage providers.
Choose based on how regularly and rapidly one restores backups, as well as how long
one wants to retain the backups. Consider using the vendor’s hot storage for backups
that require quick and/or frequent restores because it offers the fastest and most
economical retrieval. Consider shifting data to archive storage for long-term archiving,
Although data retrieval may be more time-consuming and expensive, storage expenses
are far lower, especially if one intends to preserve backups for many years. The ability to
automatically shift data between tiers is a feature that some vendors offer. This
minimizes administration and makes it easier to obtain cost savings.
o 4. Regulatory Compliance
o For regulatory compliance, keeping backups in the same area as the data’s origin may
be the best option. Worldwide alternatives for data centers are provided by many cloud
suppliers. Look for a cloud storage provider that can accommodate if one needs to store
EU client data in an EU data center. Moving data to cloud storage within the same region
is also advantageous for performance. Even if you are not subject to regulation, the
enhanced performance might be valuable to you.
o 5. Ransomware/Malware Protection
o Ransomware is plain nasty. Unfortunately, it frequently makes the news. The malware
will search the network for shares that contain files and documents to encrypt in addition
to the locally infected computer, which is one of the more frightening characteristics of
ransomware. You might be relieved to learn that your cloud storage can assist prevent
ransomware by providing some backup security advantages because it’s more difficult to
 access without proper authentication if you’re hit by ransomware or another type of
malware that is encrypting or destroying files.
o 6. Usability or Accessibility
o The key advantages of cloud storage are accessibility and usability. You can rapidly
upload your file to your online drive even if you lack technical ability because they both
have simple user interfaces. Most cloud data storage providers include drag-and-drop
functionality and an intuitive user interface. For instance, if you saved a file to a disc on a
mobile device, you can access that file on a computer or any other device with internet
access. It doesn’t matter where you are right now. Your files, which are kept online in
one of the data centers, can be accessed if you have a strong internet connection.
o 7. Flexibility
o In general, using the cloud gives businesses more flexibility than hosting on a local
server. Additionally, a cloud-based solution could be able to quickly meet your need for
more bandwidth without necessitating a difficult (and expensive) update to your IT
infrastructure. This improved independence and flexibility may considerably raise the
overall effectiveness of your firm. You won’t be able to focus on achieving your
company’s goals and satisfying consumers if your present IT solutions need you to
devote too much of your time to computer and data-storage concerns. However, if you
rely on a third party to manage the IT hosting and infrastructure, you’ll free up more time
for the areas of your organization that directly impact your bottom line.
o 8. Automation
o A cloud storage service may be used by multiple users, and as everything is handled
and automated by the cloud provider vendor, one user’s current task would not influence
 that of another. When you want to store a file in the cloud, cloud storage services
function like a hard drive on your computer and won’t interfere with any ongoing tasks.
o 9. Scalable
o You can upgrade the service plan if the storage included in the current plan is
insufficient. Additionally, the additional space will be provided to your data storage
environment with some new capabilities, so you won’t need to migrate any data from one
place to another. Scalable and adaptable cloud storage is offered.
o 10. Reliability
o Many people create a cloud backup of their hard disc in case their hard drive fails. The
comfort that comes from knowing that data won’t suddenly vanish one day may be well
worth the small price.
o 10 Disadvantages of Cloud Storage
o Below are the disadvantages of cloud storage:
o 1. Vulnerability
o The majority of PCs and servers that save data require an internet connection. Cloud
solutions are internet-based by nature, which means that they are linked to other
computers and servers. Thus, making them vulnerable to attacks by malicious users on
the network.
o 2. Internet Dependency
o The internet starts to be reliant on your storage. Due to the fact that the internet will
govern our world in 2022, this disadvantage will diminish. One can always save files
while offline and access them later. However, an internet connection will be required for
the update and sync.
o 3. Issues in Security and Privacy
o Uncertainties about privacy and security on the cloud are the next significant point to be
made in relation to the drawbacks of cloud storage. Confidential data must be given over
to a third-party organization in order to be stored in the cloud. One must therefore have
complete faith in the cloud vendor.
o 4. Limitations on Control
o After the user moves data to the cloud, the vendor is now in charge of it. This implies
that users must rely on the vendors to maintain their services in a safe, stable, up-and-
running, and fully functional manner. This limits the influence on data safety Nearly all
reliability is left up to the storage vendor, along with accessibility.
o 5. Cost
o Although cloud storage options are normally a cost-effective choice, they could not be
available if utilized for short-term or very small-scale projects, depending on the cloud
vendor. Users can be on the hook for 18 more months than needed, which is not
financially feasible if the demand for data storage is for 6 months but the vendor’s
minimum offer is 2 years.
o 6. Migration
o The ability to switch to another cloud service has grown much less well than other
aspects of cloud storage. As a result, many clients continue to find this scenario to be
quite difficult. Although several of these options are currently unavailable, one may
choose to migrate data to another solution if one discovers that the cloud provider does
not adequately address all of the users’ needs. If there are such options, they might be
pricey. As a result, additional expenses are now necessary, most often in the form of
 signing a deal with a second cloud-storage vendor while being bound by the terms of the
first.
o 7. Regulatory Compliances
o Only cloud storage options with the highest levels of security protection may be trusted
by financial organizations. When penalties, fines, and lawsuits are imposed because
authorities think it necessary for specific criteria for data protection, the company will be
the target, not the cloud provider.
o 8. Minimal Support
o Even when using a simple, rapid, and secure cloud solution, problems can occur
because every user and business has different wants and specifics. The absence of
support for cloud storage is one of the main difficulties there.
o 9. Features
o Each cloud service provider is unique from the others. Users may occasionally only be
able to use the basic kinds of cloud storage that cloud providers provide. As a result, one
cannot modify certain features or take advantage of all of their benefits.
o 10. Data Management
o Given that cloud storage systems have their own organizational systems, managing data
may be a pain. The system used by a cloud vendor might not work with the way one
manages their storage currently.

Cloud Service Provider Companies

Cloud Service providers (CSP) offers various services such as Software as a Service, Platform as a
service, Infrastructure as a service, network services, business applications, mobile
applications, and infrastructure in the cloud. The cloud service providers host these services in a
data center, and users can access these services through cloud provider companies using an Internet
connection.

There are the following Cloud Service Providers Companies -

Amazon Web Services (AWS)

AWS (Amazon Web Services) is a secure cloud service platform provided by Amazon. It offers
various services such as database storage, computing power, content delivery, Relational Database,
Simple Email, Simple Queue, and other functionality to increase the organization's growth.

Features of AWS
AWS provides various powerful features for building scalable, cost-effective, enterprise applications.
Some important features of AWS is given below-

o AWS is scalable because it has an ability to scale the computing resources up or down
according to the organization's demand.
o AWS is cost-effective as it works on a pay-as-you-go pricing model.
o It provides various flexible storage options.
 o It offers various security services such as infrastructure security, data encryption, monitoring &
logging, identity & access control, penetration testing, and DDoS attacks.
o It can efficiently manage and secure Windows workloads.

2. Microsoft Azure
Microsoft Azure is also known as Windows Azure. It supports various operating systems, databases,
programming languages, frameworks that allow IT professionals to easily build, deploy, and manage
applications through a worldwide network. It also allows users to create different groups for related
utilities.

Features of Microsoft Azure

o Microsoft Azure provides scalable, flexible, and cost-effective

o It allows developers to quickly manage applications and websites.
o It managed each resource individually.
o Its IaaS infrastructure allows us to launch a general-purpose virtual machine in different
platforms such as Windows and Linux.
o It offers a Content Delivery System (CDS) for delivering the Images, videos, audios, and
applications.
o 3. Google Cloud Platform
o Google cloud platform is a product of Google. It consists of a set of physical devices, such as
computers, hard disk drives, and virtual machines. It also helps organizations to simplify the
migration process.

Features of Google Cloud

o Google cloud includes various big data services such as Google BigQuery, Google
CloudDataproc, Google CloudDatalab, and Google Cloud Pub/Sub.
 o It provides various services related to networking, including Google Virtual Private Cloud
(VPC), Content Delivery Network, Google Cloud Load Balancing, Google Cloud Interconnect,
and Google Cloud DNS.
o It offers various scalable and high-performance
o GCP provides various serverless services such as Messaging, Data Warehouse, Database,
Compute, Storage, Data Processing, and Machine learning (ML)
o It provides a free cloud shell environment with Boost Mode.

4. IBM Cloud Services

IBM Cloud is an open-source, faster, and more reliable platform. It is built with a suite of advanced
data and AI tools. It offers various services such as Infrastructure as a service, Software as a service,
and platform as a service. You can access its services like compute power, cloud data & Analytics,
cloud use cases, and storage networking using internet connection.
Feature of IBM Cloud

o IBM cloud improves operational efficiency.

o Its speed and agility improve the customer's satisfaction.
o It offers Infrastructure as a Service (IaaS), Platform as a Service (PaaS), as well as Software as
a Service (SaaS)
o It offers various cloud communications services to our IT environment.

5. VMware Cloud
VMware cloud is a Software-Defined Data Center (SSDC) unified platform for the Hybrid Cloud. It
allows cloud providers to build agile, flexible, efficient, and robust cloud services.
Features of VMware

o VMware cloud works on the pay-as-per-use model and monthly subscription

o It provides better customer satisfaction by protecting the user's data.
o It can easily create a new VMware Software-Defined Data Center (SDDC) cluster on AWS
cloud by utilizing a RESTful API.
o It provides flexible storage options. We can manage our application storage on a per-application
basis.
o It provides a dedicated high-performance network for managing the application traffic and also
supports multicast networking.
o It eliminates the time and cost complexity.
6. Oracle cloud
Oracle cloud platform is offered by the Oracle Corporation. It combines Platform as a Service,
Infrastructure as a Service, Software as a Service, and Data as a Service with cloud infrastructure. It
is used to perform tasks such as moving applications to the cloud, managing development
environment in the cloud, and optimize connection performance.

Features of Oracle cloud

o Oracle cloud provides various tools for build, integrate, monitor, and secure the applications.
o Its infrastructure uses various languages including, Java, Ruby, PHP, Node.js.
o It integrates with Docker, VMware, and other DevOps tools.
o Oracle database not only provides unparalleled integration between IaaS, PaaS, and SaaS, but
also integrates with the on-premises platform to improve operational efficiency.
o It maximizes the value of IT investments.
 o It offers customizable Virtual Cloud Networks, firewalls, and IP addresses to securely support
private networks.

Simple Storage Service

Cloud Storage - AWS S3
AWS S3 is also called AWS Simple Storage Service.

S3 is a storage service.

It allows uploading any type of file.

In S3 you can set access permissions to a file.

It is object-level storage.

o S3 is a safe place to store the files.

o It is Object-based storage, i.e., you can store the images, word files, pdf files, etc.
o The files which are stored in S3 can be from 0 Bytes to 5 TB.
o It has unlimited storage means that you can store the data as much you want.
 o Files are stored in Bucket. A bucket is like a folder available in S3 that stores the files.
o S3 is a universal namespace, i.e., the names must be unique globally. Bucket contains a DNS
address. Therefore, the bucket must contain a unique name to generate a unique DNS address.

S3 is a simple key-value store

S3 is object-based. Objects consist of the following:

o Key: It is simply the name of the object. For example, hello.txt, spreadsheet.xlsx, etc. You can
use the key to retrieve the object.
o Value: It is simply the data which is made up of a sequence of bytes. It is actually a data inside
the file.
o Version ID: Version ID uniquely identifies the object. It is a string generated by S3 when you
add an object to the S3 bucket.
o Metadata: It is the data about data that you are storing. A set of a name-value pair with which
you can store the information regarding an object. Metadata can be assigned to the objects in
Amazon S3 bucket.
o Subresources: Subresource mechanism is used to store object-specific information.
o Access control information: You can put the permissions individually on your files.
Advantages of Amazon S3

o Create Buckets: Firstly, we create a bucket and provide a name to the bucket. Buckets are the
containers in S3 that stores the data. Buckets must have a unique name to generate a unique
DNS address.
o Storing data in buckets: Bucket can be used to store an infinite amount of data. You can
upload the files as much you want into an Amazon S3 bucket, i.e., there is no maximum limit to
store the files. Each object can contain upto 5 TB of data. Each object can be stored and
retrieved by using a unique developer assigned-key.
o Download data: You can also download your data from a bucket and can also give permission
to others to download the same data. You can download the data at any time whenever you
want.
o Permissions: You can also grant or deny access to others who want to download or upload the
data from your Amazon S3 bucket. Authentication mechanism keeps the data secure from
unauthorized access.
o Standard interfaces: S3 is used with the standard interfaces REST and SOAP interfaces which
are designed in such a way that they can work with any development toolkit.
o Security: Amazon S3 offers security features by protecting unauthorized users from accessing
your data.
Amazon S3 Concepts

o Buckets
o Objects
o Keys
o Regions
o Data Consistency Model
Javatpoint Services