What is Cloud Computing ? – Day 3

In the previous post we have go through about various Cloud Computing as services  iaas, paas IDaas Naas and saas.

Now in this post we will study about the cloud computing management and cloud data storage. All the information in the What is Cloud Computing series is bring from http://www.tutorialspoint.com and howstuffworks.com the main aim of this series to provide information on cloud computing and in the next few post we will look into how clouds work for java.  Now lets move on to Cloud Management.

Cloud Computing Management

It is the responsibility of cloud provider to manage resources and their performance. Management may include several aspects of cloud computing such as load balancing, performance, storage and backups, capacity, deployment , etc. Management is required to access full functionality of resources in the cloud. Cloud Management involves a number of tasks to be performed by the cloud provider to ensure efficient use of cloud resources. Here, we will discuss some of these tasks:cloud_computing-cloud_management_tasks

AUDIT SYSTEM BACKUPS

It is required to timely audit the backups to ensure you can successfully restore randomly selected files of different users. Backups can be performed in following ways:

  • Backing up files by the company, from on-site computers to the disks that reside within the cloud.
  • Backing up files by the cloud provider.

It is necessary to know if cloud provider has encrypted the data, who has access to that data and if the backup is taken at different locations, you must know where.

SYSTEM’S DATA FLOW

The managers should develop a diagram describing a detailed process flow. This process flow will describe the movement of company’s data throughout the cloud solution.

BEWARE OF VENDOR LOCK-IN

The managers must know the procedure to exit from services of a particular cloud provider. There must exist procedures, enabling the managers to export company’s data to a file and importing it to another provider.

KNOWING PROVIDER’S SECURITY PROCEDURES

The managers should know the security plans of the provider for different services:

  • Multitenant use
  • E-commerce processing
  • Employee screening
  • Encryption policy

MONITOR CAPACITY PLANNING AND SCALING CAPABILITIES

The managers should know the capacity planning in order to ensure whether the cloud provider will meet the future capacity requirement for his business or not.

It is also required to manage scaling capabilities in order to ensure services can be scaled up or down as per the user need.

MONITOR AUDIT-LOG USE

In order to identify the errors in the system, managers must audit the logs on a regular basis.

SOLUTION TESTING AND VALIDATION

It is necessary to test the solutions provided by the provider in order to validate that it gives the correct result and is error-free. This is necessary for a system to be robust and reliable.

Cloud Computing Data Storage

Cloud Storage is a service that allows to save data on offsite storage system managed by third-party and is made accessible by a web services API.

Storage Devices

Storage devices can be broadly classified into two categories:

  • Block Storage Devices
  • File Storage Devices

BLOCK STORAGE DEVICES

Block Storage Devices offer raw storage to the clients. This raw storage can be partitioned to create volumes.

FILE STORAGE DEVICES

File Storage Devices offers storage to clients in form of files, maintaining its own file system. This storage is in the form of Network Attached Storage (NAS).

Cloud Storage Classes

Cloud Storage can be broadly classified into two categories:

  • Unmanaged Cloud Storage
  • Managed Cloud Storage

UNMANAGED CLOUD STORAGE

Unmanaged Cloud Storage means that the storage is preconfigured for the consumer. The consumer cannot format nor the consumer can install own file system or change drive properties.

MANAGED CLOUD STORAGE

Managed Cloud Storage offers online storage space on demand. Managed cloud storage system presents what appears to the user to be a raw disk that the user can partition and format.

Creating Cloud Storage System

The cloud storage system stores multiple copies of data on multiple servers and in multiple locations. If one system fails, then it only requires to change the pointer to stored object’s location.

To aggregate storage assets into cloud storage systems, the cloud provider can use storage virtualization software, StorageGRID. It creates a virtualization layer that fetches storage from different storage devices into a single management system. It can also manage data from CIFSand NFS file system over the Internet. The following diagram shows how SystemGRID virtualizes the storage into storage clouds:

cloud_computing-data_storage

Virtual Storage Containers

Virtual storage containers offer high performance cloud storage systems. Logical Unit Number (LNU) of device, files and other objects are created in virtual storage containers. Following diagram shows a virtual storage container, defining a cloud storage domain:

cloud_computing-virtual_storage_containers

Challenges

Storing the data in cloud is not that simple task. Apart from its flexibility and convenience, it also has several challenges faced by the consumers. The consumers require ability to:

  • Provision additional storage on demand.
  • Know and restrict the physical location of the stored data.
  • Verify how data was erased?
  • Have access to a documented process for surely disposing of data storage hardware.
  • Administrator access control over data.

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What is Cloud Computing ? – Day 2

This is the second post on What is cloud computing. In previous post we have learn about what is the cloud computing and how its work. We have also study about its architecture, Infrastructure Components and its various model. In this post we will study on iaas, paas IDaas Naas and saas.

lnfrastructure-as-a-service

IaaSprovides access to fundamental resources such as physical machines, virtual machines, virtual storage,

etc., Apart from these resources, the IaaS also offers:

  •  Virtual machine disk storage
  •  Virtual local area network (VLANs)
  •  Load balancers
  •  IP addresses
  •  Software bundles

All of the above resources are made available to end user via server virtualization. Moreover, these resources
are accessed by the customers as if they own them. All of the above resources are made available to end user via server virtualization. Moreover, these resources are accessed by the customers as if they own them.

cloud_computing-iaas

Benefits

IaaS allows the cloud provider to freely locate the infrastructure over the Internet in a cost-effective manner. Some of the key benefits of IaaS are listed below:

  • Full Control of the computing resources through Administrative Access to VMs.
  • Flexible and Efficient renting of Computer Hardware.
  • Portability, Interoperability with Legacy Applications.

FULL CONTROL OVER COMPUTING RESOURCES THROUGH ADMINISTRATIVE ACCESS TO VMS

IaaS allows the consumer to access computing resources through administrative access to virtual machines in the following manner:

  • Consumer issues administrative command to cloud provider to run the virtual machine or to save data on cloud’s server.
  • Consumer issues administrative command to virtual machines they owned to start web server or installing new applications.

FLEXIBLE AND EFFICIENT RENTING OF COMPUTER HARDWARE

IaaS resources such as virtual machines, storages, bandwidth, IP addresses, monitoring services, firewalls, etc., all are made available to the consumers on rent. The consumer has to pay based the length of time a consumer retains a resource. Also with administrative access to virtual machines, the consumer can also run any software, even a custom operating system.

PORTABILITY, INTEROPERABILITY WITH LEGACY APPLICATIONS

It is possible to maintain legacy between applications and workloads between IaaS clouds. For example, network applications such as web server, e-mail server that normally runs on consumer-owned server hardware can also be run from VMs in IaaS cloud.

Issues

IaaS shares issues with PaaS and SaaS, such as Network dependence and browser based risks. It also have some specific issues associated with it. These issues are mentioned in the following diagram:

cloud_computing-iaas_issues

COMPATIBILITY WITH LEGACY SECURITY VULNERABILITIES

Because IaaS offers the consumer to run legacy software in provider’s infrastructure, therefore it exposes consumers to all of the security vulnerabilities of such legacy software.

VIRTUAL MACHINE SPRAWL

The VM can become out of date with respect to security updates because IaaS allows the consumer to operate the virtual machines in running, suspended and off state. However, the provider can automatically update such VMs, but this mechanism is hard and complex.

ROBUSTNESS OF VM-LEVEL ISOLATION

IaaS offers an isolated environment to individual consumers through hypervisor. Hypervisor is a software layer that includes hardware support for virtualization to split a physical computer into multiple virtual machines.

DATA ERASE PRACTICES

The consumer uses virtual machines that in turn uses the common disk resources provided by the cloud provider. When the consumer releases the resource, the cloud provider must ensure that next consumer to rent the resource does not observe data residue from previous consumer.

Characteristics

Here are the characteristics of IaaS service model:

  • Virtual machines with pre-installed software.
  • Virtual machines with pre-installed Operating Systems such as Windows, Linux, and Solaris.
  • On-demand availability of resources.
  • Allows to store copies of particular data in different locations.
  • The computing resources can be easily scaled up and down.

Cloud Computing Platform as a Service(PaaS)

PaaS offers the runtime environment for applications. It also offers development & deployment tools, required to develop applications. PaaS has a feature of point-and-click tools that enables non-developers to create web applications.

Google’s App Engine, Force.com are examples of PaaS offering vendors. Developer may log on to these websites and use the built-in API to create web-based applications.

But the disadvantage of using PaaS is that the developer lock-in with a particular vendor. For example, an application written in Python against Google’s API using Google’s App Engine is likely to work only in that environment. Therefore, the vendor lock-in is the biggest problem in PaaS.

The following diagram shows how PaaS offers an API and development tools to the developers and how it helps the end user to access business applications.

cloud_computing-paas

Benefits

Following are the benefits of PaaS model:

cloud_computing-paas_benefits

LOWER ADMINISTRATIVE OVERHEAD

Consumer need not to bother much about the administration because it’s the responsibility of cloud provider.

LOWER TOTAL COST OF OWNERSHIP

Consumer need not purchase expensive hardware, servers, power and data storage.

SCALABLE SOLUTIONS

It is very easy to scale up or down automatically based on application resource demands.

MORE CURRENT SYSTEM SOFTWARE

It is the responsibility of the cloud provider to maintain software versions and patch installations.

Issues

Like SaaS, PaaS also place significant burdens on consumer’s browsers to maintain reliable and secure connections to the provider systems. Therefore, PaaS shares many of the issues of SaaS. However, there are some specific issues associated with PaaS as shown in the following diagram:

cloud_computing-paas_issues

LACK OF PORTABILITY BETWEEN PAAS CLOUDS

Although standard languages are used yet the implementations of platforms services may vary. For example, file, queue, or hash table interfaces of one platform may differ from another, making it difficult to transfer workloads from one platform to another.

EVENT BASED PROCESSOR SCHEDULING

The PaaS applications are event oriented which poses resource constraints on applications, i.e., they have to answer a request in a given interval of time.

SECURITY ENGINEERING OF PAAS APPLICATIONS

Since the PaaS applications are dependent on network, PaaS applications must explicitly use cryptography and manage security exposures.

Characteristics

Here are the characteristics of PaaS service model:

  • PaaS offers browser based development environment. It allows the developer to create database and edit the application code either via Application Programming Interface or point-and-click tools.
  • PaaS provides built-in security, scalability, and web service interfaces.
  • PaaS provides built-in tools for defining workflow and approval processes and defining business rules.
  • It is easy to integrate with other applications on the same platform.
  • PaaS also provides web services interfaces that allow us to connect the applications outside the platform.

PaaS Types

Based on the functions, the PaaS can be classified into four types as shown in the following diagram:

cloud_computing-paas_types

STAND-ALONE DEVELOPMENT ENVIRONMENTS

The Stand-alone PaaS works as an independent entity for a specific function. It does not include licensing, technical dependencies on specific SaaS applications.

APPLICATION DELIVERY-ONLY ENVIRONMENTS

The Application Delivery PaaS includes on-demand scaling and application security.

OPEN PLATFORM AS A SERVICE

Open PaaS offers an open source software that helps a PaaS provider to run applications.

ADD-ON DEVELOPMENT FACILITIES

The Add-on PaaS allows to customize the existing SaaS platform.

Cloud Computing Software as a Service(SaaS)

Software as a Service (SaaS) model allows to provide software application as a service to the end users. It refers to a software that is deployed on a hosted service and is accessible via Internet. There are several SaaS applications, some of them are listed below:

  • Billing and Invoicing System
  • Customer Relationship Management (CRM) applications
  • Help Desk Applications
  • Human Resource (HR) Solutions

Some of the SaaS applications are not customizable such as an Office Suite. But SaaS provides us Application Programming Interface (API), which allows the developer to develop a customized application.

Characteristics

Here are the characteristics of SaaS service model:

  • SaaS makes the software available over the Internet.
  • The Software are maintained by the vendor rather than where they are running.
  • The license to the software may be subscription based or usage based. And it is billed on recurring basis.
  • SaaS applications are cost effective since they do not require any maintenance at end user side.
  • They are available on demand.
  • They can be scaled up or down on demand.
  • They are automatically upgraded and updated.
  • SaaS offers share data model. Therefore, multiple users can share single instance of infrastructure. It is not required to hard code the functionality for individual users.
  • All users are running same version of the software.

Benefits

Using SaaS has proved to be beneficial in terms of scalability, efficiency, performance and much more. Some of the benefits are listed below:

  • Modest Software Tools
  • Efficient use of Software Licenses
  • Centralized Management & Data
  • Platform responsibilities managed by provider
  • Multitenant solutions

MODEST SOFTWARE TOOLS

The SaaS application deployment requires a little or no client side software installation which results in the following benefits:

  • No requirement for complex software packages at client side
  • Little or no risk of configuration at client side
  • Low distribution cost

EFFICIENT USE OF SOFTWARE LICENSES

The client can have single license for multiple computers running at different locations which reduces the licensing cost. Also, there is no requirement for license servers because the software runs in the provider’s infrastructure.

CENTRALIZED MANAGEMENT & DATA

The data stored by the cloud provider is centralized. However, the cloud providers may store data in a decentralized manner for sake of redundancy and reliability.

PLATFORM RESPONSIBILITIES MANAGED BY PROVIDERS

All platform responsibilities such as backups, system maintenance, security, hardware refresh, power management, etc., are performed by the cloud provider. The consumer need not to bother about them.

MULTITENANT SOLUTIONS

Multitenancy allows multiple users to share single instance of resources in virtual isolation. Consumers can customize their application without affecting the core functionality.

Issues

There are several issues associated with SaaS, some of them are listed below:

  • Browser based risks
  • Network dependence
  • Lack of portability between SaaS clouds

BROWSER BASED RISKS

If the consumer visits malicious website and browser becomes infected, and the subsequent access to SaaS application might compromise the consumer’s data.

To avoid such risks, the consumer can use multiple browsers and dedicate a specific browser to access SaaS applications or can use virtual desktop while accessing the SaaS applications.

NETWORK DEPENDENCE

The SaaS application can be delivered only when network is continuously available. Also network should be reliable but the network reliability cannot be guaranteed either by cloud provider or the consumer.

LACK OF PORTABILITY BETWEEN SAAS CLOUDS

Transferring workloads from one SaaS cloud to another is not so easy because work flow, business logics, user interfaces, support scripts can be provider specific.

Open SaaS and SOA

Open SaaS uses SaaS applications that are developed using open source programming language. These SaaS applications can run on any open source operating system and database. Open SaaS has several benefits, some of these are listed below:

  • No License Required
  • Low Deployment Cost
  • Less Vendor Lock-in
  • More portable applications
  • More Robust Solution

The following diagram shows the SaaS implementation based on SOA:

cloud_computing-soa_implementation_of_saas

Cloud Computing Identity as a Service(IDaaS)

Overview

Employees in a company require to login into system to perform various tasks. These systems may be based on local server or cloud based. Following are the problems that an employee might face:

  • Remembering different username and password combinations for accessing multiple servers.
  • If an employee leaves the company, it’s required to ensure that each of the user’s account has been disabled. This increases workload on IT staff.

To solve above problems, a new technique emerged which is known as Identity as a Service (IDaaS).

IDaaS offers management of identity (information) as a digital entity. This identity can be used during electronic transactions.

Identity

Identity refers to set of attributes associated with something and make it recognizable. All objects may have same attributes, but their identity cannot be the same. This unique identity is assigned through unique identification attribute.

There are several identity services that have been deployed to validate services such as validating web sites, transactions, transaction participants, client, etc. Identity as a Service may include the following:

  • Directory Services
  • Federated Services
  • Registration
  • Authentication Services
  • Risk and Event monitoring
  • Single sign-on services
  • Identity and Profile management

Single Sign-On (SSO)

To solve the problem of using different username & password combination for different servers, companies now employ Single Sign-On software, which allows the user to login only one time and manages the user’s access to other systems.

SSO has single authentication server, managing multiple accesses to other systems, as shown in the following diagram:

cloud_computing-single_sign_on

SSO WORKING

There are several implementations of SSO. Here, we will discuss the common working of SSO:

cloud_computing-sso_working

Following steps explain the working of Single Sign-On software:

  1. User logs into the authentication server using a username and password.
  2. The authentication server returns the user’s ticket.
  3. User sends the ticket to intranet server.
  4. Intranet server sends the ticket to the authentication server.
  5. Authentication server sends the user’s security credentials for that server back to the intranet server.

If an employee leaves the company, then it just required to disable the user at the authentication server, which in turn disables the user’s access to all the systems.

Federated Identity Management (FIDM)

FIDM describes the technologies and protocols that enable a user to package security credentials across security domains. It uses Security Markup Language (SAML) to package a user’s security credentials as shown in the following diagram:

cloud_computing-fidm

OpenID

It offers users to login into multiple websites with single account. Google, Yahoo!, Flickr, MySpace, WordPress.com are some of the companies that support OpenID.

Benefits

  • Increased site conversation rates.
  • Access to greater user profile content.
  • Fewer problems with lost passwords.
  • Ease of content integration into social networking sites.

Cloud Computing Network as a Service(NaaS)

Overview

Networks as a Service allows us to access to network infrastructure directly and securely. NaaS makes it possible to deploy custom routing protocols.

NaaS uses virtualized network infrastructure to provide network services to the consumer. It is the responsibility of NaaS provider to maintain and manage the network resources which decreases the workload from the consumer. Moreover, NaaS offers network as a utility.

NaaS is also based on pay-per-use model.

How NaaS is delivered?

To use NaaS model, the consumer is required to logon to the web portal, where he can get online API. Here, the consumer can customize the route.

In turn, consumer has to pay for the capacity used. It is also possible to turn off the capacity at any time.

Mobile NaaS

Mobile NaaS offers more efficient and flexible control over mobile devices. It uses virtualization to simplify the architecture to create more efficient processes.

Following diagram shows the Mobile NaaS service elements:

cloud_computing-mobile_naas

NaaS Benefits

NaaS offers a number of benefits, some of them are discussed below:

cloud_computing-naas_benefits

INDEPENDENCE

Each consumer is independent and can segregate the network.

BURSTING

Customers have to pay for high-capacity network only when needed.

RESILIENCE

There exists reliability treatments that can be applied for critical applications.

ANALYTICS

There exists data protection solution for highly sensitive applications.

EASE OF ADDING NEW SERVICE ELEMENTS

It is very easy to integrate new service elements to the network.

SUPPORT MODELS

There exists more open support models, which help to reduce the operation cost.

ISOLATION OF CUSTOMER TRAFFIC

The customer traffic is logically isolated.

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What is Cloud Computing ? – Day 1

The practice of using a network of remote servers hosted on the Internet to store, manage, and process data, rather than a local server or a personal computer. Cloud computing is a computing term or metaphor that evolved in the late 2000s, based on utility and consumption of computer resources. Cloud computing involves deploying groups of remote servers and software networks that allow centralized data storage and online access to computer services or resources. Clouds can be classified as public, private or hybrid. by wikipedia

In cloud computing, the word cloud (also phrased as “the cloud”) is used as a metaphor for “the Internet,” so the phrase cloud computing means “a type of Internet-based computing,” where different services such as servers, storage and applications are delivered to an organization’s computers and devices through the Internet. If you google about cloud computing you will file thousand of website on that. Recently i was look for some information and i found howstuffworks.com, its really cool website and contains lots of good information on various things.  Their is good description given on how cloud computing works and most of the data in this post is belong from there. I have also get some data from  http://www.tutorialspoint.com/. I just put all the information on cloud computing together to give brief description on it.

How Cloud Works :

Let’s say you’re an executive at a large corporation. Your particular responsibilities include making sure that all of your employees have the right hardware and software they need to do their jobs. Buying computers for everyone isn’t enough — you also have to purchase software or software licenses to give employees the tools they require. Whenever you have a new hire, you have to buy more software or make sure your current software license allows another user. It’s so stressful that you find it difficult to go to sleep on your huge pile of money every night. Soon, there may be an alternative for executives like you. Instead of installing a suite of software for each computer, you’d only have to load one application. That application would allow workers to log into a Web-based service which hosts all the programs the user would need for his or her job. Remote machines owned by another company would run everything from e-mail to word processing to complex data analysis programs. It’s called cloud computing, and it could change the entire computer industry. In a cloud computing system, there’s a significant workload shift. Local computers no longer have to do all the heavy lifting when it comes to running applications. The network of computers that make up the cloud handles them instead. Hardware and software demands on the user’s side decrease. The only thing the user’s computer needs to be able to run is the cloud computing system’s interface software, which can be as simple as a Web browser, and the cloud’s network takes care of the rest.

Cloud Computing Architecture:

When talking about a cloud computing system, it’s helpful to divide it into two sections: the front end and the back end. They connect to each other through a network, usually the Internet. The front end is the side the computer user, or client, sees. The back end is the “cloud” section of the system. The front end includes the client’s computer (or computer network) and the application required to access the cloud computing system. Not all cloud computing systems have the same user interface. Services like Web-based e-mail programs leverage existing Web browsers like Internet Explorer or Firefox. Other systems have unique applications that provide network access to clients. On the back end of the system are the various computers, servers and data storage systems that create the “cloud” of computing services. In theory, a cloud computing system could include practically any computer program you can imagine, from data processing to video games. Usually, each application will have its own dedicated server.

The http://www.tutorialspoint.com/ contains very good description on cloud computing architecture.  The following information is belongs from their.

cloud_computing_architecture

cloud_computing_architecture

FRONT END

Front End refers to the client part of cloud computing system. It consists of interfaces and applications that are required to access the cloud computing platforms, e.g., Web Browser.

BACK END

Back End refers to the cloud itself. It consists of all the resources required to provide cloud computing services. It comprises of huge data storage, virtual machines, security mechanism, services, deployment models, servers, etc.

Important Points

  • It is the responsibility of the back end to provide built-in security mechanism, traffic control and protocols.
  • The server employs certain protocols, known as middleware, helps the connected devices to communicate with each other.

Cloud Infrastructure Components

Cloud infrastructure consists of servers, storage, network, management software, and deployment software and platform virtualization.

cloud_computing-cloud_infrastructural_components

cloud_computing-cloud_infrastructural_components

  • HYPERVISOR

Hypervisor is a firmware or low-level program that acts as a Virtual Machine Manager. It allows to share the single physical instance of cloud resources between several tenants.

  • MANAGEMENT SOFTWARE

Management Software helps to maintain and configure the infrastructure.

  • DEPLOYMENT SOFTWARE

Deployment software helps to deploy and integrate the application on the cloud.

  • NETWORK

Network is the key component of cloud infrastructure. It allows to connect cloud services over the Internet. It is also possible to deliver network as a utility over the Internet, i.e., the consumer can customize the network route and protocol.

  • SERVER

Server helps to compute the resource sharing and offer other services such as resource allocation and deallocation, monitoring resources, security, etc.

  • STORAGE

Cloud uses distributed file system for storage purpose. If one of the storage resource fails, then it can be extracted from another one which makes cloud computing more reliable.

  • Infrastructural Constraints

Fundamental constraints that cloud infrastructure should implement are shown in the following diagram:

cloud_computing-cloud_infrastructural_constraints

cloud_computing-cloud_infrastructural_constraints

  • TRANSPARENCY

Since virtualization is the key to share resources in cloud environment. But it is not possible to satisfy the demand with single resource or server. Therefore, there must be transparency in resources, load balancing and application, so that we can scale them on demand.

  • SCALABILITY

Scaling up an application delivery solution is not that easy as scaling up an application because it involves configuration overhead or even re-architecting the network. So, application delivery solution is need to be scalable which will require the virtual infrastructure such that resource can be provisioned and de-provisioned easily.

  • INTELLIGENT MONITORING

To achieve transparency and scalability, application solution delivery will need to be capable of intelligent monitoring.

  • SECURITY

The mega data center in the cloud should be securely architected. Also the control node, a entry point in mega data center also needs to be secure.

Public Cloud Model

The Public Cloud allows systems and services to be easily accessible to general public, e.g.,Google, Amazon, Microsoft offers cloud services via Internet.

cloud_computing-public_cloud_model

Benefits

There are many benefits of deploying cloud as public cloud model. The following diagram shows some of those benefits

cloud_computing-public_cloud_model_benefits

  • COST EFFECTIVE

Since public cloud share same resources with large number of consumer, it has low cost.

  • RELIABILITY

Since public cloud employs large number of resources from different locations, if any of the resource fail, public cloud can employ another one.

  • FLEXIBILITY

It is also very easy to integrate public cloud with private cloud, hence gives consumers a flexible approach.

  • LOCATION INDEPENDENCE

Since, public cloud services are delivered through Internet, therefore ensures location independence.

  • UTILITY STYLE COSTING

Public cloud is also based on pay-per-use model and resources are accessible whenever consumer needs it.

  • HIGH SCALABILITY

Cloud resources are made available on demand from a pool of resources, i.e., they can be scaled up or down according the requirement.

Private Cloud Model

The Private Cloud allows systems and services to be accessible with in an organization. The Private Cloud is operated only within a single organization. However, It may be managed internally or by third-party.

cloud_computing-private_cloud_model

Benefits

There are many benefits of deploying cloud as private cloud model. The following diagram shows some of those benefits:

cloud_computing-private_cloud_model_benefits

  • HIGHER SECURITY AND PRIVACY

Private cloud operations are not available to general public and resources are shared from distinct pool of resources, therefore, ensures high security and privacy.

  • MORE CONTROL

Private clouds have more control on its resources and hardware than public cloud because it is accessed only within an organization.

  • COST AND ENERGY EFFICIENCY

Private cloud resources are not as cost effective as public clouds but they offer more efficiency than public cloud.

  • Disadvantages

Here are the disadvantages of using private cloud model:

  • RESTRICTED AREA

Private cloud is only accessible locally and is very difficult to deploy globally.

  • INFLEXIBLE PRICING

In order to fulfill demand, purchasing new hardware is very costly.

  • LIMITED SCALABILITY

Private cloud can be scaled only within capacity of internal hosted resources.

  • ADDITIONAL SKILLS

In order to maintain cloud deployment, organization requires more skilled and expertise.

Hybrid Cloud Model

The Hybrid Cloud is a mixture of public and private cloud. Non-critical activities are performed using public cloud while the critical activities are performed using private cloud.

cloud_computing-hybrid_cloud_model

Benefits

There are many benefits of deploying cloud as hybrid cloud model. The following diagram shows some of those benefits:

cloud_computing-hybrid_cloud_model_benefits

  • SCALABILITY

It offers both features of public cloud scalability and private cloud scalability.

  • FLEXIBILITY

It offers both secure resources and scalable public resources.

  • COST EFFICIENCIES

Public cloud are more cost effective than private, therefore hybrid cloud can have this saving.

  • SECURITY

Private cloud in hybrid cloud ensures higher degree of security.

Disadvantages

  • NETWORKING ISSUES

Networking becomes complex due to presence of private and public cloud.

  • SECURITY COMPLIANCE

It is necessary to ensure that cloud services are compliant with organization’s security policies.

  • INFRASTRUCTURAL DEPENDENCY

The hybrid cloud model is dependent on internal IT infrastructure, therefore it is necessary to ensure redundancy across data centers.

Community Cloud Model

The Community Cloud allows system and services to be accessible by group of organizations. It shares the infrastructure between several organizations from a specific community. It may be managed internally or by the third-party.

cloud_computing-community_cloud_model

Benefits

There are many benefits of deploying cloud as community cloud model. The following diagram shows some of those benefits:

  • COST EFFECTIVE

Community cloud offers same advantage as that of private cloud at low cost.

  • Sharing Between Organizations

Community cloud provides an infrastructure to share cloud resources and capabilities among several organizations.

  • SECURITY

Community cloud is comparatively more secure than the public cloud.

ISSUES

  • Since all data is housed at one location, one must be careful in storing data in community cloud because it might be accessible by others.
  • It is also challenging to allocate responsibilities of governance, security and cost.

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