Cloud Computing Technical Interivew Questions - Part 1

1. What is cloud computing?

The cloud computing is the computing which is completely based on the Internet. It can also be defined as the next stage in the evolution of the Internet. The cloud computing uses the cloud (Internet) that provides the way to deliver the services whenever and wherever the user of the cloud needs. Companies use the cloud computing to fulfill the needs of their customers, partners, and providers. The cloud computing includes vendors, partners, and business leaders as the three major contributors. The vendors are the one who provide applications and their related technology, infrastructure, hardware, and integration.

The partners are those who offer cloud services demand and provide support service to the customers. The business leaders are the ones who use or evaluate the cloud service provided by the partners. The cloud computing enables the companies to treat their resources as a pool and not as independent resources.

2. What is a cloud?

A cloud is a combination of hardware, networks, storage, services, and interfaces that helps in delivering computing as a service. It has broadly three users which are end user, business management user, and cloud service provider. The end user is the one who uses the services provided by the cloud. The business management user in the cloud takes the responsibility of the data and the services provided by the cloud. The cloud service provider is the one who takes care or is responsible for the maintenance of the IT assets of the cloud. The cloud acts as a common center for its users to fulfill their computing needs.

3. What are the basic characteristics of cloud computing?

The four basic characteristics of cloud computing are given as follows:

• Elasticity and scalability.
• Self-service provisioning and automatic de-provisioning.
• Standardized interfaces.
• Billing self-service based usage model.

4. What is a Cloud Service?

A cloud service is a service that is used to build cloud applications. This service provides the facility of using the cloud application without installing it on the computer. It reduces the maintenance and support of the application as compared to those applications that are not developed using the cloud service. The different kinds of users can use the application from the cloud service, which may be public or private application.

5. What are main features of cloud services?

Some important features of the cloud service are given as follows:

• Accessing and managing the commercial software.
• Centralizing the activities of management of software in the Web environment.
• Developing applications that are capable of managing several clients.
• Centralizing the updating feature of software that eliminates the need of downloading the upgrades.

6. How many types of deployment models are used in cloud?

There are 4 types of deployment models used in cloud:

1. Public cloud
2. Private cloud
3. Community cloud
4. Hybrid cloud

7. What is the AppFabric component?

The AppFabric component is used to create access control and distribute messages across clouds and enterprises. It has a service-oriented architecture, and can be considered as the backbone of the Windows Azure platform. It provides connectivity and messaging among distributed applications. It also has the capabilities of integrating the applications and the business processes between cloud services and also between cloud services and global applications.

The AppFabric component provides a development environment that is integrated with Visual Studio 2010.TheWindows Communication Foundation (WCF) services built in VS 2010 can be published on cloud from the Visual Studio design environment.

The two important services of AppFabric are as follows:

• Access Control Service (ACS) - Allows rules-driven and claims-based access control for distributed applications. These claims-based rules and authorization roles can be defined in the cloud for accessing on-premise and cloud services. The claim can be a user or application attribute, which the service application expects, such as e-mail address, phone number, password, and role, for appropriate access control. When any application wants to use the Web service, it sends the required claims to ACS for requesting a token. ACS converts the input claims into output claims by following the rules of mapping. These rules are created during the configuration of ACS. The ACS issues a token containing the output claims for the consumer application. This application uses this token in the request header and sends to the Web service. This service validates the claims in the token and gives suitable access to the user.
• Service bus - Provides messaging between cross-enterprise and cross-cloud scenarios. It provides publish/subscribe, point-to-point, and queues message patterns for exchange of messages across distributed applications in the cloud. It integrates with the Access Control service to establish secure relay and communication.

8. Why does an organization need to manage the workloads?

The workload can be defined as an independent service or a set of code that can be executed. It can be everything from a data-intensive workload to storage or a transaction processing workload and does not rely upon the outside elements. The workload can be considered as a small or complete application.

The organization manages workloads because of the following reasons:

• To know how their applications are running.
• To know what functions they are performing.
• To know the charges of the individual department according to the use of the service.

9. Which services are provided by Window Azure operating system?

Windows Azure provides three core services which are given as follows:

• Compute
• Storage
• Management

10. Explain hybrid and community cloud.

The hybrid cloud consists of multiple service providers. This model integrates various cloud services for Hybrid Web hosting. It is basically a combination of private and public cloud features. It is used by the company when a company has requirements for both the private and public clouds. Consider an example when an organization wants to implement the SaaS (Software as a Service) application throughout the company. The implementation requires security that can be provided by the private cloud used inside the firewall. The additional security can be provided by the VPN on requirement. Now, the organization has both the private and public cloud features.

The community cloud provides a number of benefits, such as privacy and security. This model, which is quite expensive, is used when the organizations having common goals and requirements are ready to share the benefits of the cloud service.

11. Explain public and private cloud.

The public cloud (or external cloud) is freely available for access. You can use a public cloud to collect data of the purchasing of items from a Web site on the Internet. You can also use public cloud for the reasons, which are given as follows:

• Helps when an application is to be used by a large number of people, such as an e-mail application, on the Internet.
• Helps when you want to test the application and also needs to develop the application code.
• Helps when you want to implement the security for the application.
• Helps when you want to increase the computing capacity.
• Helps when you are working on the projects in collaboration.
• Helps when you are developing the project on an ad-hoc basis by using PaaS.

The private cloud allows the usage of services by a single client on a private network. The benefits of this model are data security, corporate governance, and reliability concerns. The private cloud is used by the organization when it has a huge, well-run data center having a lot of spare capacity. It is also used when an organization is providing IT services to its clients and the data of organization is highly important. It is best suited when the requirements are critical.

The characteristics of this model are given as follows:

• Provides capability to internal users and allows provision of services.
• Automates the tasks of management and provides the billing of consumption of a particular service.
• Offers a well-managed environment.
• Enables the optimization of computational resources, such as servers.
• Manages the workload of the hardware.
• Offers self-service based provisioning of hardware resources and software.

12. Give a brief introduction of Windows Azure operating system.

The Windows Azure operating system is used for running cloud services on the Windows Azure platform, as it includes necessary features for hosting your services in the cloud. It also provides runtime environment that consists of Web server, computational services, basic storage, queues, management services, and load balancers. The operating system provides development. Fabric for development and testing of services before their deployment on the Windows Azure in the cloud.

13. What are the advantages of cloud services?

Some of the advantages of cloud service are given as follows:

• Helps in the utilization of investment in the corporate sector; and therefore, is cost saving.
• Helps in the developing scalable and robust applications. Previously, the scaling took months, but now, scaling takes less time.
• Helps in saving time in terms of deployment and maintenance.