Cloud Computing Architecture Interview Preparation Guide

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

► Cloud Ingress
► Processor Speed
► Cloud storage services
► Cloud provided services
► Intra-cloud communications

► Launch Phase
► Monitor Phase
► Shutdown Phase
► Cleanup Phase

The zero or ultra-thin client initializes the network to gather required configuration files that then tell it where its OS binaries are stored. The entire zero client device runs via the network. This creates a single point of failure, in that, if the network goes down, the device is rendered useless.

Infrastructure as a service is taking the physical hardware and going completely virtual (e.g. all servers, networks, storage, and system management all existing in the cloud). This is the equivalent to infrastructure and hardware in the traditional (non-cloud computing) method running in the cloud. In other words, businesses pay a fee (monthly or annually) to run virtual servers, networks, storage from the cloud. This will mitigate the need for a data center, heating, cooling, and maintaining hardware at the local level

Platform as a service is cloud computing service which provides the users with application platforms and databases as a service. This is equivalent to middle-ware in the traditional (non-cloud computing) delivery of application platforms and databases.

Development as a service is web based, community shared development tools. This is the equivalent to locally installed development tools in the traditional (non-cloud computing) delivery of development tools.

The software-as-a-service (SaaS) service-model involves the cloud provider installing and maintaining software in the cloud and users running the software from their cloud clients over the Internet (or Intranet). The users' client machines require no installation of any application-specific software - cloud applications run on the server (in the cloud). SaaS is scalable, and system administration may load the applications on several servers. In the past, each customer would purchase and load their own copy of the application to each of their own servers, but with the SaaS the customer can access the application without installing the software locally. SaaS typically involves a monthly or annual fee.

► Reference architecture
► Technical architecture
► Deployment operation architecture

Cloud computing architecture refers to the components and sub components required for cloud computing. These components typically consist of a front end platform (fat client, thin client, mobile device), back end platforms (servers, storage), a cloud based delivery, and a network (Internet, Intranet, Inter-cloud). Combined, these components make up cloud computing architecture.

Hypervisor is a Virtual Machine Monitor which manages resources for virtual machines. There are mainly two types of hypervisors:
► The guest Vm runs directly over the host hardware, eg Xen, VmWare ESXI
► The guest Vm runs over hardware through a host OS, eg Kvm, oracle virtualbox

To provide the performance transparency and automation there are many tools used by cloud architecture. It allows to manage the cloud architecture and monitor reports. It also allows them to share the application using the cloud architecture. Automation is the key component of cloud architecture which helps to improve the degree of quality.

The characteristics that makes cloud architecture above traditional architecture is:
► According to the demand cloud architecture provides the hardware requirement
► Cloud architecture is capable of scaling the resource on demand
► Cloud architecture is capable of managing and handling dynamic workloads without failure

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.

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.

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.

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.

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

it provides any business process that is delivered through cloud service model using the internet and accesses the resources through the web portal.

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.

it provides the user to deploy their software and application on the cloud infrastructure using the tools that are available with the operating system.

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.

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.

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.

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.