These days, perhaps it is difficult to find a household who has no computer. Either the “sitting” job without a computer seems a kind of unusual. Sometimes I think that over the past 10 years, little has changed – computers have remained almost as they were. Accelerated, more beautiful, but that’s all. But is it really? Yes and no. Most of the changes occur seamlessly, creating new technologies and concepts. One of the most rapidly developing technology is cloud computing. It probably is not very new, but recently the rapidly evolving.

So … what is the cloud?

Cloud computing can be compared with the utilities. Everyone needs electricity, gas and water. Each of these resources have meters and pay and how much consumption. But try to imagine if the three services would have to take care of yourself. It should install and maintain electrical generators, instead of heating and electricity generation of gas used to arrange an alternative fuel, and water pumping from wells. Similarly, in the traditional computing – all programs, data and resources is the user’s computer, everything should take care of yourself. Cloud computing is all the user data and programs are needed him somewhere else, the service provider’s computers. The same user’s computer has only a minimal amount of software – operating system and Web browser. All other resources obtained from the “cloud” in the system.

Most computer users use the rudiments of the clouds long ago. Only on the unsuspecting. Internet e-mail. E-mail – one of the “cloudy” services. Need not be installed on your e-mail. E-mail client program. You have a browser and can connect to your e-mail. the mailbox. Letters and Reading “program takes care provider.

Cloud Computing concept is much broader and goes beyond the user take advantage of the programs. ” Let’s say, to get a website Services (hosting), you can order it from the cloud service provider. From the traditional services it will be different in several key factors. When you buy a traditional web site service, everything is pre-defined: how much space you have, what the maximum bandwidth, how many databases you can configure. If you subscribe to a similar service from the “cloud”, you pay only for the consumption of resources: for as much space as you load the data for both data traffic, how many users require, for both the database actions as you need them (for example, for scanning lines of the table) . Cloud computing is characterized by dynamically dividing the resources required. You may be sufficient for a virtual server with one processor, but if you take a couple of hours in an eight-processor – you can order, access and use the same again. And just for those few hours will pay a higher price.

Thus, the cloud is a huge array of computers (called cluster), interconnected network – both locally and online. If you subscribe to any cloud service – it is not “tied” to one cloud with a computer. Drivers with special cloud from the cloud, you and resources as needed at some point. You pay for the consumed resources.

Types of cloud services

Cloud service companies typically provide three types of services: software, platforms and infrastructure. Each of these services has its own niche.

Service programs

What is needed for every computer user, whether a natural person or a company? Of course – office suite. A classic example – Microsoft Office, or the free open source OpenOffice.org. That employees can use this kit, it is necessary for each of the programs installed on your computer. Both the license and the program implementation and maintenance costs a lot of money. It is much easier to take advantage of any company provided a service that allows Office programs to use just a web browser. And the records are in one place, all can be accessed and manipulated. Such a decision is – is the Google Docs applications suite. To use it, you only need a web browser. You can choose both the free version and the paid Google Apps for companies and corporations.

There are many different programs that can be delivered as cloud services. That same e-mail online. E-mail, and a variety of accounting programs, and even digital imaging program.

This service type is called the application service. You use the program through a web browser, you may pay for the number of users, perhaps for the number of documents or transactions. However, the administrator does not maintain and are not concerned about computer programs and economy. And save money and time. Wins and service providers – they develop one or more versions of the programs and allows them to paskiriems consumers or businesses. You do not need to travel to clients and manage a ton of computers.

Service platform

Platform is a hardware device and it needed a software solution installed. If, say, you’re a programmer, you probably need a computer, which is installed on LAMP (Linux, Apache, MySQL, PHP) package. Look for a separate computer to install these required components, you can create a virtual computer and using the “VirtualBox”, which you can buy this service from the cloud service provider. Everything depends on your needs. Of course, the LAMP platform is quite simple, but they are really complicated and it is not easy to install. Often really easy to order such a platform.

If you decide to book your platform, do not assume that the cloud provider will prescribe a single cloud, computer, and it will install what you need. Cloud real computers are “invisible.” Your platform is a virtual computer. One particular such virtual machine platforms can be hundreds or even thousands. Why? So that often one platform does not use all the physical hardware and virtual number – uses. So, this is just cheaper – with a smaller amount of physical equipment that can handle more users. The platforms and solutions are usually just “paruoštukai. When you subscribe to any platform that simply unpacks the cloud controller is ready for an image and a platform to “turn on”. You will receive your login and immediately be able to use the platform. Virtual platform is not “tied” to one cloud computer. If, say, a cloud computer that is your platform, heavily loaded, the platform can be moved to another less loaded computer.

Such a virtual platform, compared with the actual physical server, a ridiculously low cost. You can create all the computing center with different servers, data distribution between them, parallel computing, and so on. In addition, your platform will be much safer than a home computer – if you collapse your hard drive, you will have trouble, but if any of the cloud, hard drives – even no idea, because the data is duplicated and distributed.

Infrastructure Services

Infrastructure services are most often necessary for large companies that want to pile all the services: file servers, e-mail. mail servers, operating platforms, databases, etc. T. Usually cloud infrastructure services provided are similar to the third or even fourth-level computing centers and services. The third and fourth levels means that the system must be available to more than 99.9% of the time, even if the failure of computers, hard drives breaks or lost power. This is a duplicated system with dual power supplies and dual cooling systems and back-up power generators. Computing centers that service is not cheap, well, a cloud computing allows you to use virtual servers in computing facilities and much more “scattered” geographical infrastructure. Copy the virtual servers is much easier to replicate than the physical.

Virtualization and cloud

As already understood, cloud computing is an important role in virtual PC-platform. However, cloud computing – not just virtualization. This is a special way to use it. For example, if you create your own virtual computer, it will have almost all the normal characteristics of the computer – the processor, a certain amount of memory, a certain capacity of a virtual disk. Post a cloud platform also has the following properties, but their implementation is different. As already mentioned, the virtual computer is “alive” physical computing in the cloud, but is not “tied” to any one of them. Its file system might look normal, but physically it can be spread throughout the ten servers and hard drives. In addition, it is easily expandable. When you see that it’s too small for you 100 GB of space, with a single mouse click you will get another one hundredth Clearly, additional pay for them. A cloud exists a virtual server is extremely dynamic.

Physically, the cloud is composed of an array of computers – like one huge computer. On the basis of an open cloud management platform, “Eucalyptus” cloud issuing software consists of several components:

Cloud Control. A special component that provides a user interface with the virtualization process (computers, network and data cache).
Data storage controller. This component is responsible for the preservation of and access to virtual machine data.
The array controller. Responsible for the virtual machines and network among their management.
Cache controller. Managed by the mesh block level cache. This cache can be dynamically linked to a virtual machine.
Node controller. Manages virtual machine operations, implementation, monitoring and shut-down.

Cloud computing is the concept of virtualization and automation of dynamic resource allocation, and maximum utilization of existing equipment.

Pros and Cons

Cloud computing is attractive for its low cost and on-demand resources received. You can save greatly if you use leased resources wisely. Suppose you rented a virtual server with the CVS or SVN version control systems, you can save if you have decided that the files are loaded into the system only once a day, but not at any time.

The cloud has some drawbacks. One of them – a complex performance assessment. Virtual servers are still not as stable as natural. It is difficult to assess the delays between different servers (for example, the program and its use of the database server).

The second major disadvantage – the privacy and security. When all data is stored in the cloud computing service provider in the center, there is always the question about their security and privacy of users. This is especially important for organizations wishing to use the service infrastructure.

There have been cases where cloud services companies stopped their activities due to financial and legal factors. Their services using their bodies were a lot of trouble to move your infrastructure to the cloud, or other internal servers.

The biggest advantage of the clouds – the price of resources. A large part of the business processes required to be carried out through the clouds. And the company that co-operation system – it is perfectly able to implement Google Apps. Your e-mail. E-mail to the firm’s domain will be considered to Google’s servers, and you can read them at the same time, Google Mail or via e-mail. E-mail client. You will be able to share calendars, contacts and other pertinent information. You can store documents in Google Docs system, no additional costs such as office software.

However, the key cloud computing is the lack of its availability. If you temporarily lose your Internet connection – and you lose all the programs that you can use. Useful when all documents and e-mail. E-mail is accessible from anywhere, but if there is no internet connection, these resources will not reach.

Or may be useful for cloud computing the average person? Of course, many programs, services are free. Platform services are paid for, but worth the money. Imagine that you want to quickly convert to BluRay drive is now a popular H264 encoded *. mkv movie. On the occasion of your computer, you can do so within 10-20 hours. However, if you have the ability to quickly transmit large amounts of data, you may want to rent a cloud of 32 processors and convert the movie in an hour or two?