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Simply put， cloud computing is the delivery of computing services—including servers， storage， databases， networking， software， analytics， and intelligence—over the Internet （“the cloud”） to offer faster innovation， flexible resources， and economies of scale. You typically pay only for cloud services you use， helping lower your operating costs， run your infrastructure more efficiently and scale1 as your business needs change.

Top benefits of cloud computing

Cloud computing is a big shift from the traditional way businesses think about IT resources. Here are seven common reasons organisations are turning to cloud computing services：

Cost

Cloud computing eliminates the capital expense of buying hardware and software and setting up and running on-site2 datacenters—the racks of servers， the round-the-clock electricity for power and cooling， the IT experts for managing the infrastructure. It adds up fast.

Speed

Most cloud computing services are provided self service and on demand， so even vast amounts of computing resources can be provisioned in minutes， typically with just a few mouse clicks， giving businesses a lot of flexibility and taking the pressure off capacity planning.

Global scale

The benefits of cloud computing services include the ability to scale elastically. In cloud speak3， that means delivering the right amount of IT resources—for example， more or less computing power， storage， bandwidth—right when it is needed and from the right geographic location.

Productivity

On-site datacenters typically require a lot of “racking and stacking4”— hardware setup， software patching， and other time-consuming IT management chores. Cloud computing removes the need for many of these tasks， so IT teams can spend time on achieving more important business goals.

Performance

The biggest cloud computing services run on a worldwide network of secure datacenters， which are regularly upgraded to the latest generation of fast and efficient computing hardware. This offers several benefits over a single corporate datacenter， including reduced network latency for applications and greater economies of scale.

Reliability

Cloud computing makes data backup， disaster recovery and business continuity easier and less expensive because data can be mirrored5 at multiple redundant sites on the cloud providers network.

Security

Many cloud providers offer a broad set of policies， technologies and controls that strengthen your security posture overall， helping protect your data， apps and infrastructure from potential threats.

Types of cloud computing

There are three different ways to deploy cloud services： on a public cloud， private cloud or hybrid cloud.

Public cloud

Public clouds are owned and operated by a third-party cloud service providers， which deliver their computing resources like servers and storage over the Internet. Microsoft Azure6 is an example of a public cloud. With a public cloud， all hardware， software and other supporting infrastructure is owned and managed by the cloud provider. You access these services and manage your account using a web browser.

Private cloud

A private cloud refers to cloud computing resources used exclusively by a single business or organisation. A private cloud can be physically located on the companys on-site datacenter. Some companies also pay third-party service providers to host their private cloud. A private cloud is one in which the services and infrastructure are maintained on a private network.

Hybrid cloud

Hybrid clouds combine public and private clouds， bound together by technology that allows data and applications to be shared between them. By allowing data and applications to move between private and public clouds， a hybrid cloud gives your business greater flexibility， more deployment options and helps optimise your existing infrastructure， security and compliance.

Types of cloud services： IaaS， PaaS， serverless and SaaS

Most cloud computing services fall into four broad categories： infrastructure as a service （IaaS）， platform as a service （PaaS）， serverless and software as a service （SaaS）. These are sometimes called the cloud computing stack because they build on top of one another.

Infrastructure as a service （IaaS）

This is the most basic category of cloud computing services. With IaaS， you rent IT infrastructure—servers and virtual machines （VMs）， storage， networks， operating systems—from a cloud provider on a pay-as-you-go basis.

Platform as a service （PaaS）

Platform as a service refers to cloud computing services that supply an on-demand environment for developing， testing， delivering and managing software applications. PaaS is designed to make it easier for developers to quickly create web or mobile apps， without worrying about setting up or managing the underlying infrastructure of servers， storage， network and databases needed for development.

Serverless computing

Overlapping with PaaS， serverless computing focuses on building app functionality without spending time continually managing the servers and infrastructure required to do so. The cloud provider handles the setup， capacity planning and server management for you. Serverless architectures are highly scalable and event-driven， only using resources when a specific function or trigger occurs.

Software as a service （SaaS）

Software as a service is a method for delivering software applications over the Internet， on demand and typically on a subscription basis. With SaaS， cloud providers host and manage the software application and underlying infrastructure and handle any maintenance， like software upgrades and security patching. Users connect to the application over the Internet， usually with a web browser on their phone， tablet or PC.

Uses of cloud computing

The first cloud computing services are barely a decade old， but already a variety of organisations—from tiny startups to global corporations， government agencies to non-profits—are embracing the technology for all sorts of reasons.

Here are a few examples of what is possible today with cloud services from a cloud provider：

Create cloud-native7 applications

Quickly build， deploy and scale applications—web， mobile and API8. Take advantage of cloud-native technologies and approaches， such as containers， Kubernetes9， microservices architecture， API-driven communication and DevOps10.

Test and build applications

Reduce application development cost and time by using cloud infrastructures that can easily be scaled up or down.

Store， back up and recover data

Protect your data more cost-efficiently—and at massive scale—by transferring your data over the Internet to an offsite cloud storage system that is accessible from any location and any device.

Analyse data

Unify your data across teams， divisions and locations in the cloud. Then use cloud services， such as machine learning and artificial intelligence， to uncover insights for more informed decisions.

Stream11 audio and video

Connect with your audience anywhere， anytime， on any device with high-definition video and audio with global distribution.

Embed intelligence

Use intelligent models to help engage customers and provide valuable insights from the data captured.

Deliver software on demand

Also known as software as a service （SaaS）， on-demand software lets you offer the latest software versions and updates around to customers—anytime they need， anywhere they are.

簡单来说，云计算就是通过因特网（“云”）提供计算服务——包括服务器、存储功能、数据库、联网、软件、分析功能和智能功能——以加快创新、使资源配置更灵活，实现规模经济。通常你只需为自己所使用的云服务付费，这有助于降低运营成本，更高效地运行基础设施，并根据业务需求的变化作出调整。

云计算的好处

云计算不同于企业对IT资源的传统认知，它是一项重大变革。以下是各机构选择云计算服务的七个常见理由。

成本

云计算免除了用以购买硬件和软件以及构建并运行本地数据中心的资本支出，包括服务器机架、机器运行和冷却需要的全天候供电，还有维护基础设施的IT专业人员——这些费用增长很快。

速度

大多数云计算服务都可自助按需提供，通常只要点几下鼠标，即便是海量计算资源也能在几分钟之内配置好，这给了企业极大的灵活性，也减轻了容量规划的压力。

全球范围

云计算服务的其中一个好处就是弹性缩放的能力。用云术语来讲，这意味着在刚好需要的时候，从合适的地理位置交付恰当数量的IT资源，例如，更多或更少的计算能力、存储空间和带宽。

生产率

本地数据中心通常需要做许多与“机架和堆栈”相关的工作，包括设置硬件、给软件打补丁，以及其他耗时的日常IT管理事务。云计算省去了对其中很多工作的需求，因此IT团队可以有时间实现更重要的商业目标。

性能

最大的云计算服务都在各安全数据中心所组成的全球网络上运行，这些数据中心定期升级为最新一代快速高效的计算硬件。相比单个企业数据中心，这有几点好处，包括减少应用程序的网络延迟和扩大规模经济效应。

可靠性

云计算使得数据备份、灾难恢复和保持业务连续性更容易，费用更低，因为数据可做成镜像保存在云提供商网络的多个冗余站点上。

安全性

很多云提供商提供各种政策、技术和控制工具，全面加强你的安全态势，有助于保护你的数据、应用程序和基础设施免遭潜在威胁。

云计算的种类

云服务有三种不同的使用方式：公有云、私有云或混合云。

公有云

公有云由第三方云服务提供商所有和运营，云服务提供商通过因特网提供他们的计算资源，如服务器和存储功能。微软的Azure就是公有云的一个例子。在公有云中，所有的硬件、软件和其他支持性基础设施均由云提供商所有和管理。你可以用网页浏览器来获得这些服务并管理你的账户。

私有云

私有云是指专供单个企业或机构使用的云计算资源。私有云可实际位于公司的本地数据中心内。有些公司也会雇请第三方服务提供商托管他们的私有云。私有云是在专用网络上维护服务和基础设施的云。

混合云

混合云结合了公有云和私有云的特点，通过共享数据和应用程序的技术将两者连接在一起。通过允许数据和应用程序在私有云和公有云之间移动，混合云可以为企业提供更大的灵活性和更多的部署策略，帮助优化企业现存的基础设施、安全性和兼容性。

云服务的类型：基础设施即服务，平台即服务，无服务器，软件即服务

大多数云计算服务可以分成四大类：基础设施即服务，平台即服务，无服务器和软件即服务。这些服务有时会被称为云计算堆栈，因为它们是逐层建构的。

基础设施即服务

这是云计算服务中最基础的类型。使用基础设施即服务时，你以即用即付的方式从云提供商处租用IT基础设施，包括服务器和虚拟机、存储空间、网络、操作系统。

平台即服务

平台即服务指的是按需提供环境用于开发、测试、交付和管理软件应用的云计算服务。平台即服務旨在让开发者更轻松地快速构建网页端或移动端应用程序，而无须操心设置或管理开发所需的服务器、存储功能、网络和数据库等基础设施。

无服务器计算

无服务器计算与平台即服务有所重合，专注于构建应用程序的功能，无须在持续管理必要的服务器和基础设施上花费时间。云提供商为你处理设置、容量规划和服务器管理事宜。无服务器架构可伸缩性强，而且由事件驱动，只有在特定函数或触发器发生时才会使用资源。

软件即服务

软件即服务是指通常以订阅方式经由因特网按需交付软件应用程序的方式。使用软件即服务时，云提供商托管软件应用程序和基础设施并负责所有维护工作，如升级软件、打安全补丁。用户通常用手机、平板电脑或个人电脑上的网页浏览器通过因特网连接到应用程序。

云计算的用途

距第一批云计算服务问世还不到十年，但已有各种机构——从小型初创企业到跨国公司，从政府机构到非盈利机构——因各种原因采用云计算技术。

以下是目前云提供商所能提供的云服务的一些实例：

构建云原生应用程序

快速构建、部署和缩放应用程序，包括网页端、移动端和应用程序编程接口。利用云原生技术和方法，比如容器、Kubernetes、微服务架构、API驱动的通信和DevOps。

测试和构建应用程序

通过使用可轻松升降级的云基础设施来缩减应用程序的开发成本和时间。

存储、备份和数据恢复

通过将数据由因特网传送到从任何位置、任何设备都可访问的场外云存储系统中，以超大规模和更具成本效益的方式保护数据。

分析数据

统一云中各团队、各部门、各地区的数据。然后用云服务（例如机器学习和人工智能）发掘洞见以做出更有根据的决定。

在线播放音频和视频

用遍布全球的高清视频和音频在任何地点、任何时间、任何设备上与受众进行联系。

内嵌智能

用智能模式来吸引客户，利用捕获的数据提供有价值的见解。

按需提供软件

按需软件也被称为软件即服务，可以让你向客户提供最新的软件版本和更新——无论他们身在何处，何时需要。

（译者为“《英语世界》杯”翻译大赛获奖者）