Thursday, 6 June 2013

Cloud Computing Basic Interview Question answer

 

Cloud Computing Basic

What is Hypervisor in Cloud Computing and its types?

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

Are Type-1 Hypervisors better in performance than Type-2 Hypervisors and Why?

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.

What are the characteristics on which a Cloud Computing Model should be selected for implementing and managing workload?
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.

What do you understand by CaaS?

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.

What is the minimal requirement to implement an IAAS Cloud?

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

How is the Cloud Computing different from primitive Client-Server Architecture?

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.

Why should one prefer public cloud over private cloud?

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.

Is it cost effective to implement a private cloud rather than a public cloud and why?

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.

Does network topology play an important role in deciding the success of a Cloud Infrastructure?

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.

Is Cloud Computing an application?

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.
 

Cloud Computing Architecture


What is the use of defining cloud architecture?

Cloud architecture is a software application that uses on demand services and access pool of resources from the cloud. Cloud architecture act as a platform on which the applications are built. It provides the complete computing infrastructure and provides the resources only when it is required. It is used to elastically scale up or down the resources according to the job that is being performed.

How does cloud architecture overcome the difficulties faced by traditional architecture?

Cloud architecture provide large pool of dynamic resources that can be accessed any time whenever there is a requirement, which is not being given by the traditional architecture. In traditional architecture it is not possible to dynamically associate a machine with the rising demand of infrastructure and the services. Cloud architecture provides scalable properties to meet the high demand of infrastructure and provide on-demand access to the user.

What are the three differences that separate out cloud architecture from the tradition one?

The three differences that make cloud architecture in demand are:
1. Cloud architecture provides the hardware requirement according to the demand. It can run the processes when there is a requirement for it.
2. Cloud architecture is capable of scaling the resources on demand. As, the demand rises it can provide infrastructure and the services to the users.
3. Cloud architecture can manage and handle dynamic workloads without failure. It can recover a machine from failure and always keep the load to a particular machine to minimum.

What are the advantages of cloud architecture?

Cloud architecture uses simple APIs to provide easily accessible services to the user through the internet medium. It provides scale on demand feature to increase the industrial strength. It provides the transparency between the machines so that users don't have to worry about their data. Users can just perform the functionality without even knowing the complex logics implemented in cloud architecture. It provides highest optimization and utilization in the cloud platform

What is the business benefits involved in cloud architecture?

1. Zero infrastructure investment: Cloud architecture provide user to build large scale system with full hardware, machines, routers, backup and other components. So, it reduces the startup cost of the business.
2. Just-in-time Infrastructure: It is very important to scale the infrastructure as the demand rises. This can be done by taking cloud architecture and developing the application in the cloud with dynamic capacity management.
3. More efficient resource utilization: Cloud architecture provides users to use their hardware and resource more efficiently and utilize it in a better way. This can be done only by applications request and relinquish resources only when it is needed (on-demand).
What are the examples of cloud architectures on which application can run?
There are lot of examples that uses cloud architecture for their applications like:
1. Processing Pipelines
Uses like document processing pipelines that convert documents of any form into raw searchable text.
- Image processing pipelines: Create thumbnails or low resolution image
- Video transcoding pipelines: Convert video from one form to another online
- Indexing: Create an index of web crawl data
- Data mining: Perform search over millions of records
2. Batch Processing Systems
- Systems that uses log management or generate reports.
- Automated Unit Testing and Deployment Testing
3. Websites
- Instant Websites: websites for conferences or events
- Promotion websites
What are the different components required by cloud architecture?
There are 5 major components of cloud architecture.
1. Cloud Ingress:
Provides a mean to communicate with the outside world. This can be done with the help of communication methods such as:
- Queue based communications
- HTTP communications
- REST/SOAP
- Service Bus
2. Processor Speed:
Processor speed is the major section on which the whole cloud architecture is based. It provides on demand resources that can be dynamically allocated to the user. It saves lots of cost and has many benefits of virtualization.
3. Cloud storage services:
Cloud services provide means to store data to user's applications. It is used to provide services for different types of storages like: table data, files.
4. Cloud provided services:
Additional services are provided by the cloud, like data services, payment processing services, and search or web functionality services.
5. Intra-Cloud communications:
it provides a way to communicate with other systems that are using cloud architecture. Providers usually provide services so that one user can communicate easily with another user by being on cloud.
What are the different phases involves in cloud architecture?
There are four phases that basically gets involved in the cloud architecture:
1. Launch phase: It launches the basic services and makes the system ready for communication and for application building
2. Monitor phase: It monitors the services that is being launched and then manages them so that on demand the user will be able to get what he wants.
3. Shutdown phase: It shutdown the services that are not required first and after all the services gets shutdown, and then it closes the system services.
4. Cleanup phase: It clean up the left out processes and services that is being either broken or didn't get shutdown correctly.
What is the relationship between SOA and cloud architecture?
Service oriented architecture (SOA) is an architectural style that supports service oriented methodology that is being added in the cloud architecture as a mandatory component. Cloud architecture support the use of on-demand access to resources and it provides lots of other facilities that are being found in SOA as well. SOA makes these requirements optional to use. But, to get the full functionality and more performance based efficiency there is a requirement for the mixture of SOA and cloud architecture.
How does the Quality of service is being maintained in the cloud architecture?
Cloud architecture mainly focuses on quality of service. It is a layer that manages and secures the transmission of the resources that is being acquired by on-demand access. Quality of service is being maintained such that it increases the performance, automated management, and support services. Cloud architecture provides easy to use methods and proper ways to ensure the quality of service. It is represented by a common cloud management platform that delivers many cloud services based on the same foundation.
What are the different roles defined by cloud architecture?
Cloud architecture defines three roles:
- Cloud service consumer: it is used to provide different services to the consumer on demand.
- Cloud service provider: here provider provides the services to meet the requirements of the user by monitoring the traffic and demands that are coming.
- Cloud service Creator: here creator is used to create the services and provide the infrastructure to the user to use and give the access to the resources. The roles that are being defined can be performed by one person or it can be performed by many people together. There can be more roles defined depending on the cloud architecture and the complexity with which it will scale.
What are the major building blocks of cloud architecture?
The major building blocks of cloud architecture are:
1. Reference architecture: it is used for documentation, communication, designing and defining various types of models
2. Technical Architecture: defines the structured stack, structure the cloud services and its components, show the relationship that exist between different components, management and security
3. Deployment Operation Architecture: it is used to operate and monitor the processes and the services.
What are the different cloud service models in cloud architecture?
There are 4 types of cloud service models available in cloud architecture:
1. Infrastructure as a service:
It provides the consumer with hardware, storage, network and other resources on rent. Through this consumer can deploy and run software using dedicated software. This includes the operating system and the applications that are associated with it.
2. Platform as a service:
it provides the user to deploy their software and application on the cloud infrastructure using the tools that are available with the operating system.
3. Software as a service: it provides the users the ability to run its application on the cloud infrastructure and can access it from any client device using any interface like web browser.
4. Business Process as a service: it provides any business process that is delivered through cloud service model using the internet and accesses the resources through the web portal.

What is the difference between vertical scale up and Horizontal scale out?

- Vertical scale up provides more resources to a single computational unit, whereas horizontal scale out provides additional computational unit and run them in parallel.
- Vertical scale up provides a provision to move a workload to other system that doesn't have workload, whereas horizontal scale out split the workload among various computational units.
- Vertical scale up doesn't have a database partitioning concept, whereas horizontal scale out provides the database partitioning.

How does cloud architecture provide performance transparency and automation?

There are lots of tools that are being used by the cloud architecture to provide the performance transparency and automation. The tools allow the user to monitor report and manage the cloud architecture. It also allows them to share the applications using the cloud architecture. Automation is the key component of cloud architecture as it provides the services to increase the degree of the quality. It brings the capacity on demand and allows the requirements of the user to be met.


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