Basic Cloud Computing Interview Preparation Guide

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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