Deployment Models of Cloud Computing

• Public cloud

Applications, storage, and other resources are made available to the general public by a service provider. Public cloud services may be free or offered on a pay-per-usage model. There are limited service providers like Microsoft, Google etc. owns all Infrastructures at their Data Center and the access will be through Internet mode only. No direct connectivity proposed in Public Cloud Architecture. 

• Community cloud

Community cloud shares infrastructure between several organizations from a specific community with common concerns (security, compliance, jurisdiction, etc.), whether managed internally or by a third-party and hosted internally or externally. The costs are spread over fewer users than a public cloud (but more than a private cloud), so only some of the cost savings potential of cloud computing are realized.

• Hybrid cloud

Hybrid cloud is a composition of two or more clouds (private, community or public) that remain unique entities but are bound together, offering the benefits of multiple deployment models.

• Private cloud

Private cloud is infrastructure operated solely for a single organization, whether managed internally or by a third-party and hosted internally or externally.

They have attracted criticism because users "still have to buy, build, and manage them" and thus do not benefit from less hands-on management, essentially "[lacking] the economic model that makes cloud computing such an intriguing concept".

Possibilities of virtualization in different scenario

Possibilities of virtualization in different scenario 

When we say virtualization in computer technology we think of running multiple systems and services on a single machines with multiple operating systems. So at the time of implementing the person working on it would think multiple situations which might help him in different ways, but implementing virtualization is not always good as it also contains some flaws and needs to be implemented with good knowledge and it also demands some minimum requirements for its implementation.

When anyone think of virtualization very first thing comes in mind is cost cutting and flexibility. So every organization thinks of doing it in every possible way by overcoming the technical and economical feasibility.

                If someone thinks of implementing virtualization on a scenario where numbers of users are very few (1-15) so, in this case implementing this thing would be costly rather than cost cutting. But if someone thinks of using virtualization in case of servers and then using them to provide services to number of users (minimum 30 to maximum number of user depending upon the capability of configuration of machine) would help him to reduce the cost and man power also, but this will only help if we implement virtualization along with some other features so that we can use our resources at the maximum capability of it(example Thin Clients on user end). Now if we think of providing services to our users using virtualization we will need good network as we will be providing services in same office or it might be over the public network. So network will work as backbone of this architecture and admin or designer must ensure that the network is capable of doing this as we will be providing services from one location and if access to that location goes down then no one will be capable of working.

                Hardware and Software requirements for implementing virtualization in an organization for providing services.

• One machine with configuration of resources capable of running multiple servers on it with enough resources so that it can handle multiple remote users to log on and work simultaneously and can handle there working and it must be virtualization enabled. Suppose a case of providing platform for development of application and Database for that using terminal services to 25-30 users then it will need minimum Core i5 processor or higher with 16GB of RAM and hard disk depending upon the amount of data storage with high Input/output capability.

• Then it will be required to provide Thin clients (Hardware) to user as they will be doing there all the processing at the server end so no or very less processing is required if in organization they got some old machines which are not capable of running such applications can also be used as they only need to run only a very simple operating system and we can convert it to thin client using thin client application. Using this we will eliminate the cost of buying new machines buy making alive the old ones.

• Network will be backbone of the working environment in this scenario so it must be good and properly connected.

•  In this case security will be a bigger concern so admin must keep eye on the permissions and must restrict unauthorized users from accessing the system so, for this we can use firewall (hardware or software) with our required configurations.

• For virtualization we will need software which enable machine to handle multiple operating systems and make sure that they all work as standalone machine. For this we can use Esxi (Vmware product) or ZEN or any other available software.

• Making servers we will need server operating systems depending upon the requirement of platform to be provided and in this we can use Microsoft Server 2008 or Linux based Server Operating system.

• For providing services through terminal services we need to install it and need to buy it on per user basis and install it.

• For accessing Esxi server we need Vsphere or Vcenter on a machine so that we can handle Servers.

• If our data is of large size and its input/output requirement is large then we need to install a SAN storage system for fast movement and storage of data.