The concept and introduction of cloud computing
1. What is cloud computing
In 2006, Amazon brought the powerful computing power gathered based on the distributed operating system to thousands of ordinary users through the Internet.The online service of computing is called cloud computing.
The popular explanation is: the powerful computing power of the distributed operating system, like water, electricity and gas, has become a necessity for the public and delivered to thousands of households, so that everyone can efficiently use this computing resource. Just like a faucet, when we need water, we can turn on the faucet and use it. Someone once highly summarized the great changes that cloud computing has brought to people's lives:In the era of cloud computing, people use computing resources as convenient as water and electricity. When you turn on the tap, there is tap water to use, and when you turn on the switch, there is electricity available.
Example: Suppose you need to calculate the weather tomorrow, all the data are ready, use your own computer to calculate. But my computer's computing power is limited, and it takes a year to calculate the results, so our calculation results are worthless. (The weather forecast is time-sensitive) But we can't buy servers specifically for weather forecasting. In order to reduce costs, we need to use cloud computing. We only need to transfer the calculation method to the cloud, and let the cloud server (the cloud server is connected by a group of computers with powerful computing capabilities) calculate the result and return it to your computer. We only need to pay the corresponding fee.
2. Features of Cloud Computing
The characteristic of cloud computing is,One is to have large-scale computing power, and the other is to enable computing power to be shared with millions of households like hydropower and coal.In the era of data explosion, organizations such as the military and enterprises urgently need huge data group services. With the development of Web sites and e-commerce, the Internet has become one of the necessities that people cannot live without. In a remote data center, thousands of computers and servers are connected to form a computer cloud. Therefore, cloud computing can even allow you to experience 10 trillion operations per second. With such a powerful computing power, you can simulate nuclear explosions, predict climate change, and market development trends. Users access the data center through computers, laptops, mobile phones, etc., and perform calculations according to their needs. Cloud computing technology has obvious advantages.
The technical advantages of cloud computing include:Rapid deployment and expansion, strong stability, safety and reliability, easy integration, low cost, etc.. For an enterprise, having cloud computing services is equivalent to acquiring the top-notch IT infrastructure. In the traditional model, companies need to purchase their own hardware and software systems, which requires internal IT personnel to maintain. With the shift of business to the cloud, companies do not need to hire as many IT maintenance personnel as before, reducing labor costs.
Three. Three deployment modes of cloud computing
1. Public cloud
Public cloud refers to the cloud that provides services for external customers. All its services are for others to use, not for themselves.(At present, typical public clouds include Microsoft’s Windows Azure Platform, Amazon’s AWS, Salesforce.com, and domestic Alibaba, UFIDA, etc. For users, the biggest advantage of public clouds is that the programs they use , Services and related data are stored at the provider of the public cloud, and there is no need to make corresponding investment and construction. The biggest problem at present is that because the data is not stored in its own data center, its security is at risk. At the same time , The availability of public clouds is not controlled by users, and there are also certain uncertainties in this regard.
2. Private cloud
Private cloud refers to the cloud used by the enterprise itself. All its services are not for others to use, but for internal personnel or branches.. The deployment of private cloud is more suitable for large enterprises or government departments with many branches. With the centralization of these large-scale enterprise data centers, private clouds will become their mainstream mode of IT system deployment. Compared with public cloud, private cloud is deployed inside the enterprise itself, so its data security and system availability can be controlled by itself. But its disadvantage is that the investment is relatively large, especially the one-time construction investment.
3. Hybrid cloud
Hybrid cloud refers to a cloud that is used by itself and its customers. The services it provides can be used by others or by itself. In comparison, the deployment of hybrid cloud has higher requirements for providers.
The explanation of the three clouds is:
Public cloud: I built a cloud platform myself and sold it to others (selling services).
Private cloud: It is generally used by enterprises or internal companies. Larger companies develop their own use and will not use it for others, so they are called private cloud.
Hybrid cloud: I can't use up my cloud, and I sell the rest to others.
Four. Three service models of cloud computing
The three service models of cloud computing are: IaaS, PaaS and SaaS.
The popular explanation of the three service models is:
IaaS: equivalent to computer host
PaaS: equivalent to operating system
SaaS: equivalent to application software
Detailed introduction:
1. IaaS: Infrastructure-as-a-Service (Infrastructure as a Service)
The first layer is called IaaS, sometimes also called Hardware-as-a-Service. A few years ago, if you want to run some enterprise applications on the office or company website, you need to buy a server or other expensive hardware to control Local application, let your business run. But now with IaaS, you can outsource the hardware to other places. IaaS companies will provide off-site servers, storage and network hardware, which you can rent. Saving maintenance costs and office space, the company can use these hardware to run its applications at any time. Some large IaaS companies include Amazon, Microsoft, VMWare, Rackspace and Red Hat. However, these companies have their own expertise. For example, Amazon and Microsoft not only provide you with IaaS, they will also rent out their computing power to you. host your website.
2. PaaS: Platform-as-a-Service (Platform as a Service)
The second layer is the so-called PaaS, sometimes called middleware. All your company's development can be carried out on this layer, saving time and resources. PaaS companies provide various solutions for developing and distributing applications on the Internet, such as virtual servers and operating systems. This saves you money on hardware and makes collaboration between dispersed studios easier. Web application management, application design, application virtual hosting, storage, security and application development collaboration tools. Some major PaaS providers are Google App Engine, Microsoft Azure, Force.com, Heroku, Engine Yard. Recent companies that have emerged are AppFog, Mendix and Standing Cloud
3.SaaS: Software-as-a-Service (Software as a Service)
The third layer is the so-called SaaS. This layer is the one that comes into contact with your life every day, mostly through web browsers. Any application on a remote server can be run over the network, which is SaaS. The services you consume are completely entered into these categories from web pages such as Netflix, MOG, Google Apps, Box.net, Dropbox or Apple's iCloud. Although these web services are used for business and entertainment or both, they are also part of cloud technology. Some SaaS applications used for business include Citrix's GoToMeeting, Cisco's WebEx, Salesforce's CRM, ADP, Workday, and SuccessFactors.