30 Cloud Computing Interview Questions and Answers

How does cloud computing provides on-demand functionality?

Cloud computing is a metaphor used for internet. It provides on-demand access to virtualized IT resources that can be shared by others or subscribed by you. It provides an easy way to provide configurable resources by taking it from a shared pool. The pool consists of networks, servers, storage, applications and services.

What is the difference between scalability and elasticity?

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 are the different layers of cloud computing?

Cloud computing consists of 3 layers in the hierarchy and these are as follows:
1. Infrastructure as a Service (IaaS) provides cloud infrastructure in terms of hardware like memory, processor speed etc.
2. Platform as a Service (PaaS) provides cloud application platform for the developers.
3. Software as a Service (SaaS) provides cloud applications which are used by the user directly without installing anything on the system. The application remains on the cloud and it can be saved and edited in there only.

What resources are provided by infrastructure as a service?

Infrastructure as a Service provides physical and virtual resources that are used to build a cloud. Infrastructure deals with the complexities of maintaining and deploying of the services provided by this layer. The infrastructure here is the servers, storage and other hardware systems.

How important is platform as a service?

Platform as a Service is an important layer in cloud architecture. It is built on the infrastructure model, which provides resources like computers, storage and network. This layer includes organizing and operate the resources provided by the below layer. It is also responsible to provide complete virtualization of the infrastructure layer to make it look like a single server and keep it hidden from the outside world.

What does software as a service provide?

Software as Service is another layer of cloud computing, which provides cloud applications like google is doing, it is providing google docs for the user to save their documents on the cloud and create as well. It provides the applications to be created on fly without adding or installing any extra software component. It provides built in software to create wide varieties of applications and documents and share it with other people online.

What are the different deployment models?

Cloud computing supports many deployment models and they are as follows:
• Private Cloud
Organizations choose to build there private cloud as to keep the strategic, operation and other reasons to themselves and they feel more secure to do it. It is a complete platform which is fully functional and can be owned, operated and restricted to only an organization or an industry. More organizations have moved to private clouds due to security concerns. Virtual private cloud is being used that operate by a hosting company.

• 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.

• 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. It allows organizations to create their own cloud and allow them to give the control over to someone else as well.

What are the different datacenters deployed for this?

Cloud computing is made up of various datacenters put together in a grid form. It consists of different datacenters like:
• Containerized Datacenters
These are the traditional datacenters that allow high level of customization with servers, mainframe and other resources. It requires planning, cooling, networking and power to access and work.

• Low-Density Datacenters
These datacenters are optimized to give high performance. In these datacenters the space constraint is being removed and there is an increased density. It has a drawback that with high density the heat issue also creeps in. These datacenters are very much suitable to develop the cloud infrastructure.

What is the use of API’s in cloud services?

API stands for Application programming interface is very useful in cloud platforms as it allows easy implementation of it on the system. It removes the need to write full fledged programs. It provides the instructions to make the communication between one or more applications. It also allows easy to create application with ease and link the cloud services with other systems.

What are the different modes of software as a service?

Software as a Service provides cloud application platform on which user can create application with the tools provided.

The modes of software as a service are defined as:
1. Simple multi-tenancy: in this each user has its own resources that are different from other users. It is an inefficient mode where the user has to put more time and money to add more infrastructure if the demand rises in less time to deliver.
2. Fine grain multi-tenancy: in this the functionality remains the same that the resources can be shared to many. But it is more efficient as the resources are shared not the data and permission within an application.

What is the security aspects provided with cloud?

Security is one of the major aspects which come with any application and service used by the user. Companies or organizations remain much more concerned with the security provided with the cloud.

There are many levels of security which has to be provided within cloud environment such as:
• Identity management: it authorizes the application service or hardware component to be used by authorized users.
• Access control: permissions has to be provided to the users so that they can control the access of other users who are entering the in the cloud environment.
• Authorization and authentication: provision should be made to allow the authorized and authenticated people only to access and change the applications and data.

What is the difference between traditional datacenters and cloud?

Cloud computing uses the concept of datacenter as it is the datacenter is based on the tradition one so the difference between them are as follows:
- Cost of the traditional datacenter is higher, due to heating issues and other hardware/software related issues but this is not the case with the cloud computing infrastructure.
- It gets scaled when the demand increases. Most of the cost is being spent on the maintenance being performed on the datacenters, whereas cloud platform requires minimum maintenance and not very expert hand to handle them.

What are the three cost factors involves in cloud data center?

Cloud data center doesn’t require experts to operate it, but it requires skilled people to see the maintenance, maintain the workloads and to keep the track of the traffic. The labor cost is 6% of the total cost to operate the cloud data center. Power distribution and cooling of the datacenter cost 20% of the total cost. Computing cost is at the end and is the highest as it is where lots of resources and installation has to be done. It costs the maximum left percentage.

How the cloud services are measured?

Cloud computing provides the services to the organizations so they can run their applications and install them on the cloud. Virtualization is used to deploy the cloud computing models as it provides a hidden layer between the user and the physical layer of the system. The cloud services are measured in terms of use. Pay as much as you use that can be on the basis of hours or months or years. Cloud services allow users to pay for only what they use and according to the demand the charges or the prices gets increased.

What are the optimizing strategies used in cloud?

To optimize the cost and other resources there is a concept of three-data-center which provides backups in cases of disaster recovery and allows you to keep all the data intact in the case of any failure within the system. System management can be done more efficiently by carrying out pre-emptive tasks on the services and the processes which are running for the job. Security can be more advanced to allow only the limited users to access the services.

What are different data types used in cloud computing?

Cloud computing is going all together for a different look as it now includes different data types like emails, contracts, images, blogs, etc. The amount of data increasing day by day and cloud computing is requiring new and efficient data types to store them. For example if you want to save video then you need a data type to save that. Latency requirements are increasing as the demand is increasing. Companies are going for lower latency for many applications.

What are the security laws which take care of the data in the cloud?

The security laws which are implements to secure data in the cloud are as follows:
Input validation: controls the input data which is being to any system.
Processing: control that the data is being processed correctly and completely in an application.
File: control the data being manipulated in any type of file.
Output reconciliation: control the data that has to be reconciled from input to output.
Backup and recovery: control the security breaches logs and the problems which has occurred while creating the back.

How to secure your data for transport in cloud?

Cloud computing provides very good and easy to use feature to an organization, but at the same time it brings lots of question that how secure is the data, which has to be transported from one place to another in cloud. So, to make sure it remains secure when it moves from point A to point B in cloud, check that there is no data leak with the encryption key implemented with the data you sending.

What do you understand from VPN?

VPN stands for virtual private network; it is a private cloud which manages the security of the data during the transport in the cloud environment. VPN allows an organization to make a public network as private network and use it to transfer files and other resources on a network.

What does a VPN consists of?

VPN is known as virtual private network and it consists of two important things:
1. Firewall: it acts as a barrier between the public network and any private network. It filters the messages that are getting exchanged between the networks. It also protects from any malicious activity being done on the network.
2. Encryption: it is used to protect the sensitive data from professional hackers and other spammers who are usually remain active to get the data. With a message always there will be a key with which you can match the key provided to you.

Name few platforms which are used for large scale cloud computing

There are many platforms available for cloud computing but to model the large scale distributed computing the platforms are as follows:
1. MapReduce: is software that is being built by Google to support distributed computing. It is a framework that works on large set of data. It utilizes the cloud resources and distributes the data to several other computers known as clusters. It has the capability to deal with both structured and non-structured data.
2. Apache Hadoop: is an open source distributed computing platform. It is being written in Java. It creates a pool of computer each with hadoop file system. It then clusters the data elements and applies the hash algorithms that are similar. Then it creates copy of the files that already exist.

What are some examples of large cloud providers and their databases?

Cloud computing has many providers and it is supported on the large scale. The providers with their databases are as follows:
• Google bigtable: it is a hybrid cloud that consists of a big table that is spilt into tables and rows. MapReduce is used for modifying and generating the data.
• Amazon SimpleDB: is a webservice that is used for indexing and querying the data. It allows the storing, processing and creating query on the data set within the cloud platform. It has a system that automatically indexes the data.
• Cloud based SQL: is introduced by Microsoft and it is based on SQL database. it provides data storage by the usage of relational model in the cloud. The data can be accessed from the cloud using the client application.

What are some open source cloud computing platform databases?

Cloud computing platform has various databases that are in support. The open source databases that are developed to support it is as follows:
1. MongoDB: is an open source database system which is schema free and document oriented database. It is written in C++ and provides tables and high storage space.
2. CouchDB: is an open source database system based on Apache server and used to store the data efficiently
3. LucidDB: is the database made in Java/C++ for data warehousing. It provides features and functionalities to maintain data warehouse.

What essential things a user should know before going for cloud computing platform?

A user should know some parameters by which he can go for the cloud computing services. The parameters are as follows:
1. User should know the data integrity in cloud computing. It is a measure to ensure integrity like the data is accurate, complete and reasonable.
2. Compliance: user should make sure that proper rules and regulations are followed while implementing the structure.
3. Loss of data: user should know about the provisions that are provided in case of loss of data so that backup and recovery can be possible.
4. Business continuity plans: user should think about does the cloud services provide him uninterrupted data resources.
5. Uptime: user should know about the uptime the cloud computing platform provides and how helpful it is for the business.
6. Data storage costs: user should find out about the cost which you have to pay before you go for cloud computing.

What are system integrators?

Systems integrators are the important part of cloud computing platform. It provides the strategy of the complicated process used to design a cloud platform. It includes well defined architecture to find the resources and the characteristics which have to be included for cloud computing. Integrators plan the users cloud strategy implementation. Integrators have knowledge about data center creation and also allow more accurate private and hybrid cloud creation.

What is the requirement of virtualization platforms in implementing cloud?

Virtualization is the basis of the cloud computing and there are many platforms that are available like VMware is a technology that provides the provision to create private cloud and provide a bridge to connect external cloud with private cloud.
There are three key features that have to be identified to make a private cloud that is:
- Cloud operating system.
- Manage the Service level policies
- Virtualization keeps the user level and the backend level concepts different from each other so that a seamless environment can be created between both.

What is the use of eucalyptus in cloud computing environment?

Eucalyptus stands for “Elastic Utility Computing Architecture for Linking
Your Programs to Useful Systems” and provides an open source software infrastructure to implement clusters in cloud computing platform. It is used to build private, public and hybrid clouds. It can also produce your own datacenter into a private cloud and allow you to extend the functionality to many other organizations. Eucalyptus provides APIs to be used with the web services to cope up with the demand of resources used in the private clouds.

Explain different layers which define cloud architecture

Cloud computing architecture consists of many layers which help it to be more organized and can be managed from one place.
The layers are as follows:
1. Cloud controller or CLC is the top most level in the hirerachy which is used to manage the virtualized resources like servers, network and storage with the user APIs.
2. Walrus is used for the storage and act as a storage controller to manage the demands of the users. It maintains a scalable approach to control the virtual machine images and user data.
3. Cluster Controller or CC is used to control all the virtual machines for executions the virtual machines are stored on the nodes and manages the virtual networking between Virtual machines and external users.
4. Storage Controller or SC provides a storage area in block form that are dynamically attached by Virtual machines.
5. Node Controller or NC is at the lowest level and provides the functionality of a hypervisor that controls the VMs activities, which includes execution, management and termination of many instances.

How user will gain from utility computing?

Utility computing allow the user to pay per use means whatever they are using only for that they have to pay. It is a plug in that needs to be managed by the organizations on deciding what type of services has to be deployed from the cloud. Utility computing allows the user to think and implement the services according to them. Most organizations go for hybrid strategy that combines internal delivered services that are hosted or outsourced services.

Is there any difference in cloud computing and computing for mobiles?

Mobile cloud computing uses the same concept but it just adds a device of mobile. Cloud computing comes in action when a task or a data get kept on the internet rather then individual devices. It provides users on demand access to the data which they have to retrieve. Applications run on the remote server, and then given to the user to be able to, store and manage it from the mobile platform.