Advanced Cloud Computing Interview Questions - Part 3

Introduction to Cloud Computing

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.

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).

Cloud computing – Amazon 

What are the different components used in AWS?

The components that are used in AWS are:
1. Amazon S3: it is used to retrieve input data sets that are involved in making a cloud architecture and also used to store the output data sets that is the result of the input.
2. Amazon SQS: it is used for buffering requests that is received by the controller of the Amazon. It is the component that is used for communication between different controllers.
3. Amazon SimpleDB: it is used to store intermediate status log and the tasks that are performed by the user/
4. Amazon EC2: it is used to run a large distributed processing on the Hadoop cluster. It provides automatic parallelization and job scheduling.

What are the uses of Amazon web services?

Amazon web services consist of a component called as Amazon S3 that acts as a input as well used as an output data store. It is used in checking the input and according to that gives the output. The input consists of the web that is stored on Amazon S3 as object and it is update frequently to make the changes in the whole architecture. It is required due to the on demand growing of the data set and to provide persistent storage.

How to use Amazon SQS?

Amazon SQS is a message passing mechanism that is used for communication between different connectors that are connected with each other. It also acts as a communicator between various components of Amazon. It keeps all the different functional components together. This functionality helps different components to be loosely coupled, and provide an architecture that is more failure resilient system.

How buffer is used in Amazon web services?

Buffer is used to make the system more resilient to burst of traffic or load by synchronizing different component. The components always receive and process the requests in unbalanced way. Buffer keeps the balance between different components and makes them work at the same speed to provide faster services.

What is the need of the feature isolation in Amazon web services?

Isolation provides a way to hide the architecture and gives an easy and convenient way to the user to use the services without any difficulty. When a message is passed between two controllers then a queue is maintained to keep the message. No controller calls any other controller directly. The communication takes place between the controllers by storing their messages in a queue. It is a service that provides a uniform way to transfer the messages between different application components. This way all the controllers are kept isolated from each other.

Cloud Computing – MapReduce

What do you understand by MapReduce?

MapReduce is a software framework that was created by Google. It`s prime focus was to aid in distributed computing, specifically large sets of data on a group of many computers. The frameworks took its inspiration from the map and reduce functions from functional programming.

Explain how mapreduce works.

The processing can occur on data which are in a file system (unstructured ) or in a database ( structured ). The mapreduce framework primarily works on two steps:
1. Map step
2. Reduce step

Map step: During this step the master node accepts an input (problem) and splits it into smaller problems. Now the node distributes the small sub problems to the worker node so that they can solve the problem.

Reduce step: Once the sub problem is solved by the worker node, the node returns a solution to the master node which accepts all the solutions of the worker node and re-compiles them into a solution. This solution is for the input that was provided to the master node.

What is an input reader in reference to mapreduce?

The input reader as the name suggests primarily has two functions:
1. Reading the Input
2. Splitting it into sub-parts

The input reader accepts a user entered problem and then it divides/splits the problem into parts which then each are assigned a map function. Also an input reader will always read data from a stable storage source only to avoid problems.

Ubuntu Cloud

What components have been released by ubuntu for their for their cloud strategy? Ubuntu till date has released three components, they are named as : - Ubuntu Server Edition on Amazon EC2 (IaaS) - Ubuntu enterprise cloud powered by Eucalyptus (IaaS) - UbuntuOne(SaaS) The first two components are targeted for the infrastructure layer of the computer stack. And UbuntuOne is meant for the software layer also known as Software as a service (SaaS). List out a few of the uses of the private cloud concept. The private cloud concept has a variety of usage scenarios. Some of them are : - It enables an organization to rapidly develop and also prototype cloudware applications. Also this can be done behind a firewall enabling the creation/development of privacy sensitive applications such as classified data handling. - Being an elastic platform it enables the use of high performance applications whose load can be fluctuating. The system is based on aggregated peak loads of different applications at a single point of time. - By using private cloud concept the organization can assign a pool of hardware inside the firewall henceforth enabling it to be assigned to the users by a common gui to speed up the process. What does private cloud offer in building an infrastructure? Private cloud offers complete set of development tools and easy to configure panel where you can customize and deploy prototype applications. - It keeps the private sensitive application separate and hidden from the world. - It provides the provision to create high performance applications and include the concept of elasticity. - It uses a firewall and keeps all the resources in a pool that separates them with other resources that are made public. What are elements included in ubuntu cloud architecture? The elements that are included in ubuntu cloud architecture are: 1. Cloud controller: it is the main controller that controls the communication between two nodes and allows the system to communicate with each other. 2. Walrus Storage controller: It controls the storage of the data and resource at one place for easy access. 3. Elastic block storage controller: it uses the elasticity concept and allow the resources to scale up as the demand rises. This block consists of dynamic resources. 4. Cluster controller: it controls the cloud clusters which are made up of mady nodes and contains the configuration of all the nodes from a single point. 5. Node controller: it consists of the hardware resources that is being provided to the web or to the user through cluster controller.