Basic Cloud Computing Interview Questions And Answers

The Cloud Computing is not an application but it is a methodology that deploys application in a custom fashion on a server. It can be also learned as an advance model of client-server architecture that is highly flexible, scalable and configurable. This architecture leverages high performance out of machines with quite an ease of management.

The hypervisor is a virtual machine monitor (VMM) that manages resources for virtual machines. The name hypervisor is suggested as it is a supervisory tool for the virtual machines. There are mainly two types of hypervisors :

Type-1: the guest Vm runs directly over the host hardware, e.g Xen, Hyper-V, VmWare ESXi

Type-2: the guest Vm runs over hardware through a host OS, e.g Kvm, Oracle virtualbox

Yes the Type-1 Hypervisors are better in performance as compared to Type-2 hypervisors because Type-1 hypervisors does not run through a host OS, they utilize all resources directly from Host hardware. In cloud implementation Type-1 hypervisors are used rather than Type-2 because Cloud servers need to run multiple OS images and it should be noted that if OS images are run on host a OS as in case of Type-2, the resources will get wasted.

Scalability is a characteristic of cloud computing through which increasing workload can be handled by increasing in proportion the amount of resource capacity. It allows the architecture to provide on demand resources if the requirement is being raised by the traffic. Whereas, elasticity is being one of the characteristic provide the concept of commissioning and decommissioning of large amount of resource capacity dynamically. It is measured by the speed by which the resources are coming on demand and the usage of the resources.

CaaS is a terminology given in telecom industry as Communication as a Service. The Voice-over-Ip (VoIP) follows a same delivery model. CaaS can offer the enterprise user features such as desktop call control, presence, unified messaging, and desktop faxing. In addition to the enterprise features, CaaS also has a set of services for contact center automation that includes IVR, ACD, call recording, multimedia routing (e-mail and text chat), and screen pop integration.

These are the platforms which are public means open to the people for use and deployment. For example, google, amazon etc. They focus on a few layers like cloud application, infrastructure providing and providing platform markets.

Organizations choose to build their private cloud as to keep the strategic, operation and other reasons to themselves and they feel more secure to do it.

It is the combination of public and private cloud. It is the most robust approach to implement cloud architecture as it includes the functionalities and features of both the worlds.

The network topology plays a vital role in selecting a cloud model and success of that model

Public Cloud
These are the platforms which are public means open to the people for use and deployment. For example, google, amazon etc. They focus on a few layers like cloud application, infrastructure providing and providing platform markets.

Private Cloud
Organizations choose to build their private cloud as to keep the strategic, operation and other reasons to themselves and they feel more secure to do it.

Hybrid Clouds
It is the combination of public and private cloud. It is the most robust approach to implement cloud architecture as it includes the functionalities and features of both the worlds.

The minimal requirement to implement are basically three things:

• OS to support hypervisor or a hypervisor.
- Preferably open-source software like Linux and Xen hypervisor

• Networking topology and implementation.
- Public Network or Private network with Level 3 Switch

• Selection of cloud model as per requirement or business.
- SaaS, Software as a Service
- PaaS, Platform as a Service
- CaaS, Communication as a Service

The primitive Client-Server architecture is a one-to-one communication between only two physical machines namely Client machine and Server machine (datacenter). Whereas the cloud computing, infrastructure is similar at the client side but varies at server-side. The server-side contains a main Cloud Controller that forwards the request to its worker machines known as Nodes. These nodes are a grid computing machines that dedicate all its resources to process application. These nodes are maintained in clusters. So a cloud computing infrastructure is quite complicated on server side that processes all the requests from clients and send the result back.

The cloud technology is the best example of sustainable technology that utilizes all the computing resources. If a person needs to setup a quick business and wants to host its website, he need not require to setup a full-fledged private cloud. Rather he should go for public cloud hosting that provides different pay-per-use subscriptions, which could actually result in being economical. There are numbers of vendors that provide such services like godaddy.com etc.

It depends on the type of business that demands a cloud setup. Suppose if the subscription on a public cloud for an application that is to be deployed on OS images is proving to be more costly then to buy some new datacenters and maintain them. Then obviously the a private cloud has to be setup instead of a public cloud. This public clouds follow utility billing methodology as electricity bill for example.

The platforms that are used for large scale cloud computing are:
► Apache Hadoop
► MapReduce

The different deployment models in cloud computing are:
► Private Cloud
► Public Cloud
► Community Cloud
► Hybrid Cloud

Utility computing allows the user to pay only for what they are using. It is a plug-in managed by an organization which decides what type of services has to be deployed from the cloud.
Most organizations prefer hybrid strategy.

► Identity management:
► Access control:
► Authentication and Authorization:

In Cloud Computing, systems integrator provides the strategy of the complicated process used to design a cloud platform. Integrator allows to create more accurate hybrid and private cloud network, as integrators have all the knowledge about the data center creation.

Cloud computing consists of different datacenters like:
► Containerized Datacenters
► Low Density Datacenters

► Professional cloud
► Personal cloud
► Performance cloud

The different layers of cloud computing are:
► SaaS: Software as a Service (SaaS), it provides users access directly to the cloud application without installing anything on the system.
► IaaS: Infrastructure as a service, it provides the infrastructure in terms of hardware like memory, processor speed etc.
► PaaS: Platform as a service, it provides cloud application platform for the developers

The benefits involved in cloud architecture is:
► Zero infrastructure investment
► Just in time infrastructure
► More efficient resource utilization

Window Azure provides three core services which are given as:
► Compute
► Storage
► Management

It authorizes the application services.

Allows only the authorized and authenticated user only to access the data and applications.