What is meant by cloud computing?

Technology that makes use of the remote service over the internet to manage, access and store data online instead of local drives is known as cloud computing. Instead of maintaining physical servers’ data centers, users can use technology services. The data includes files, documents, images, video, audio, etc. However, the cloud refers to the internet or network.

In networking, cloud computing describes a range of computing concepts that has large computers connected over a real-time communication network known as the internet.

Purpose of cloud computing

Cloud computing is used to develop new services and applications. It helps to backup, store, and analysis the data. Cloud computing is used in streaming both audios and videos, delivering the software based on the demand, and host websites and blogs.

Basic concepts of cloud computing

There are models and services which work behind to make cloud computing more accessible and feasible to the end-users. The working models of cloud computing are,

• Deployment model.
• Service model.

Deployment model

The deployment model in cloud computing defines the specific cloud environment type depending on the scale, access, purpose, cloud nature, and ownership. Cloud deployment defines the server’s location and who controls those servers. Specifies the look of cloud infrastructure. It also defines the relationship between user and infrastructure. The four different types of deployment models in cloud computing are,

• Public cloud.
• Private cloud.
• Hybrid cloud.
• Community cloud.

Public cloud

The public cloud is easily accessible by the general public. Public cloud is useful for the organization with fluctuating and growing demands. This is a great choice for companies which has a low-security concern. The deployment and configuration are easy, quick, and make a unique choice to the test environment.

Example: Google, LinkedIn, and Facebook.

Private cloud

Private cloud accesses the service and system within an organization. Private cloud infrastructure can be customized based on the organization’s requirement and it is suitable to the organization which prefers cost efficiency, data, and resource control. This is integrated along with the organization’s data centers and controlled by the IT team.

Example: Microsoft, HP data center, and Elastra-private cloud.

Hybrid cloud

A hybrid cloud is a combination of both the private and public cloud, where the critical activities are handled by the private cloud and the public cloud handles the non-critical activities. The resources are offered either by the external or internal providers. This is mostly used for cloud bursting; that is when an organization executes an application on-site, it can explode into a public cloud when the load becomes heavy.

Example: Amazon Web Services (AWS), Google Cloud, and Microsoft Azure.

Community cloud

Community cloud is the same as pubic cloud, whereas the access is to a specified set of users or organization, and this is a major difference. The users or organizations will share similar use cases, objectives and also share the same infrastructure. It is managed either by the organizations present in the community or by a third party.

Example: United States (U.S) federal agencies.

Service model

Cloud computing has various cloud services, which are defined based on the user companies, roles, service providers. The three major models and services of cloud computing are,

• Infrastructure-as-a-service (IaaS).
• Platform-as-a-service (PaaS).
• Software-as-a-service (SaaS).

IaaS

IaaS gives on-demand access to computing resources. IaaS is a cloud provider which manages the infrastructure including network, data storage, servers, and virtualization through internet connection; whereas the user can manage operating system (OS), middleware, and application(apps). IaaS has a big computer resource and it has the responsibility to maintain and run them, whereas, the client just needs internet and computer to access these resources. The user can access IaaS either through the dashboard or API. The responsibility of cloud providers is to take care of repairs, hardware issues, and outages. The payment in IaaS is based on usage and it is a multi-tenant virtualized environment.

Example: Azure virtual machine, AWS EC2 instance.

PaaS

PaaS helps the consumer to develop an environment on-demand for testing, developing, managing service, and delivering.  This is an efficient method to develop databases, mobile applications and the administrator need not worry about managing or developing the infrastructure. PaaS simply refers to application and hardware; whereas, the cloud provider manages the software platform and the user manages the applications and data present in the apps.  PaaS is a multi-tenant environment with high scalability and also has a multi-tier architecture.

Example: Microsoft Azure Web Apps, Google App Engine.

SaaS

SaaS is also known as cloud application or cloud-based software and guarantee the end-user by delivering software application as a service, which is managed by the cloud provider. The applications in SaaS can be either mobile apps or web applications, where the user can easily access through the browser. SaaS takes care of all software updates, software maintenance, and bugs. API or dashboard is used to connect the cloud application. SaaS allows team access to the software rather than installing the app locally on each user’s computer. The payment in SaaS is based on usage and it is a multi-tenant environment with a highly scalable architecture.

Example: Salesforce, dropbox.

Advantages of cloud computing

• Scalability: Computer resources are supplied based on the demand.
• Accessibility: Independence in location and device to access stored information over the internet.
• Cost: The maintenance cost for both the software and hardware are reduced by cloud computing.
• Data security: Cloud computing has many security features and make sure the data is handled and stored securely.
• Storage capacity: Cloud computing provides a large amount of storage to store necessary data like images, video, audio, document, etc.

Disadvantages of cloud computing

• Security: The organization’s sensitive data are sent to a service provider(third party). There are chances to hack those over sensitive data.
• Internet: In cloud computing all the data is stored and accessed by using internet. Without a proper internet connection, the data stored in the cloud cannot be accessed.
• Vendor lock-in: This problem arises while transferring the organization’s service form one vendor to another vendor. As the platform provided by the vendor will vary, it will cause difficulty in moving the cloud.
• Control: Service provider will manage and monitor the cloud infrastructure; whereas, users have limited control over the service.
• Flexibility: There is no possibility to have computing resources with special customization.

Context and Applications

This topic is important for postgraduate and undergraduate courses, particularly for, Bachelors in Computer Science and Engineering and Associate of Science in Computer Science.

Practice Problems

Question 1: Select the cloud services.

a) IaaS

b) PaaS

C) SaaS

d) All the above

Answer: Option d is correct.

Explanation: Cloud computing has various cloud services, and the three major cloud services are IaaS, PaaS, and SaaS. The cloud services are defined based on the user companies, roles, service providers.

Question 2: Which cloud provider hosts OS software at the data centers?

a) IaaS

b) PaaS

C) SaaS

d) None of the above

Answer: Option b is correct.

Explanation: The cloud provider in PaaS will host everything in the data centers which includes middleware, OS software, hardware, software stack, and database.

Question 3: ___ is called cloud-based software.

a) IaaS

b) PaaS

c) SaaS

d) All the above

Answer: Option c  is correct.

Explanation: The other name for SaaS is cloud application or cloud-based software which guarantee the end-user by delivering software applications.  The applications in SaaS can be accessed through the web browser.

Question 4:Which one of the following is not a type of deployment model in cloud computing?

a) IBM cloud

b) Public cloud

C) Private cloud

d) Hybrid cloud

Answer: Option a is correct.

Explanation: The four different types of deployment models in cloud computing are, public, private, hybrid, and community cloud. The deployment model in cloud computing defines the location and who controls the servers.

Question 5: Google is an example of ___ cloud.

a) IBM cloud

b) Public cloud

C) Private cloud

d) Hybrid cloud

Answer: Option b is correct.

Explanation: The general public can easily access the public cloud and Google is one example. In the public cloud deployment and configuration are easy and quick.