What is the cloud? | Cloud definition

云是由全球数据中心中的服务器组成。 迁移到云可以帮助公司节省资金,同时方便用户。

学习目标

阅读本文后,您将能够:

  • 了解“云”的含义
  • 了解云是怎样工作的
  • 探索各种不同的云模型和可能的云部署

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什么是云?

"The cloud" refers to servers that are accessed over the Internet, and the software and databases that run on those servers. Cloud servers are located in data centers all over the world. By using cloud computing, users and companies do not have to manage physical servers themselves or run software applications on their own machines.

What is the Cloud Diagram

The cloud enables users to access the same files and applications from almost any device, because the computing and storage takes place on servers in a data center, instead of locally on the user device. This is why a user can log in to their Instagram account on a new phone after their old phone breaks and still find their old account in place, with all their photos, videos, and conversation history. It works the same way with cloud email providers like Gmail or Microsoft Office 365, and with cloud storage providers like Dropbox or Google Drive.

对于企业而言,转换为云计算可以削减一些 IT 成本和开销:例如,不再需要更新和维护自己的服务器,因为他们选用的云供应商会做这些工作。这对于那些可能无力负担自己的内部基础设施,但可以通过云以经济实惠的价格将其基础设施需求外包的小型企业来说,影响尤为显著。有了云,员工和客户可以从任何位置访问相同的文件和应用程序,因此,可以使公司更轻松地进行跨国经营。

云计算是怎样工作的?

Cloud computing is possible because of a technology called virtualization. Virtualization allows for the creation of a simulated, digital-only "virtual" computer that behaves as if it were a physical computer with its own hardware. The technical term for such a computer is virtual machine. When properly implemented, virtual machines on the same host machine are sandboxed from one another, so they do not interact with each other at all, and the files and applications from one virtual machine are not visible to the other virtual machines even though they are on the same physical machine.

虚拟机还可以更有效地利用托管它们的硬件。通过一次运行多台虚拟机,一台服务器就变成了多台服务器,而一个数据中心也变成了一整群数据中心,同时为许多企业提供服务。因此,相比于采用其他方式,云提供商能够以非常低的成本,同时向比原来多得多的客户提供其服务器的使用权利。

即使个别服务器出现故障,云服务器一般都能始终在线且始终可用。通常,云供应商会跨多区域在多台计算机上备份他们的服务。

Users access cloud services either through a browser or through an app, connecting to the cloud over the Internet — that is, through many interconnected networks — regardless of what device they are using.

云计算的主要服务模型有哪些?

云服务模型

软件即服务(SaaS)SaaS 应用程序托管在云服务器上且用户可通过 Internet 访问它们,因此,不需要用户在自己的设备上安装应用程序。SaaS 就像租房子:房东负责维护房屋,但是租户通常可以像使用自己的房屋一样进行使用。SaaS 应用程序的示例有 Salesforce、MailChimp 和 Slack。

平台即服务(PaaS):在这种服务模型中,公司不需要为托管应用程序付费,而是需要为构建自己的应用程序时所需的事物付费。PaaS 供应商提供通过 Internet 构建应用程序所需的一切,包括开发工具、基础设施和操作系统。PaaS 可以比作租用建造房屋所需的所有工具和设备,而不是租用房屋本身。PaaS 示例包括 Heroku 和 Microsoft Azure。

Infrastructure-as-a-Service (IaaS): In this model, a company rents the servers and storage they need from a cloud provider. They then use that cloud infrastructure to build their applications. IaaS is like a company leasing a plot of land on which they can build whatever they want — but they need to provide their own building equipment and materials. IaaS providers include DigitalOcean, Google Compute Engine, and OpenStack.

以前,SaaS、PaaS 和 IaaS 是云计算的三个主要服务模型,并且基本上所有云服务都属于这些类别之一。但是,最近几年出现了第四种服务模型:

Function-as-a-Service (FaaS): FaaS, also known as serverless computing, breaks cloud applications down into even smaller components that only run when they are needed. Imagine if it were possible to rent a house one little bit at a time: for instance, the tenant only pays for the dining room at dinner time, the bedroom while they are sleeping, the living room while they are watching TV, and when they are not using those rooms, they don't have to pay rent on them.

FaaS or serverless applications still run on servers, as do all these models of cloud computing. But they are called "serverless" because they do not run on dedicated machines, and because the companies building the applications do not have to manage any servers.

Also, serverless functions scale up, or duplicate, as more people use the application — imagine if the tenant's dining room could expand on demand when more people come over for dinner! Learn more about serverless computing (FaaS).

云部署有哪些不同类型?

与上面讨论的定义如何通过云提供服务的模型相比,这些不同的云部署类型与云服务器的位置以及由谁管理有关。

最常见的云部署有:

  • Private cloud: A private cloud is a server, data center, or distributed network wholly dedicated to one organization.
  • Public cloud: A public cloud is a service run by an external vendor that may include servers in one or multiple data centers. Unlike a private cloud, public clouds are shared by multiple organizations. Using virtual machines, individual servers may be shared by different companies, a situation that is called "multitenancy" because multiple tenants are renting server space within the same server.
  • Hybrid cloud: hybrid cloud deployments combine public and private clouds, and may even include on-premises legacy servers. An organization may use their private cloud for some services and their public cloud for others, or they may use the public cloud as backup for their private cloud.
  • Multi-cloud: multi-cloud is a type of cloud deployment that involves using multiple public clouds. In other words, an organization with a multi-cloud deployment rents virtual servers and services from several external vendors — to continue the analogy used above, this is like leasing several adjacent plots of land from different landlords. Multi-cloud deployments can also be hybrid cloud, and vice versa.

Cloudflare 如何帮助企业迁移到云并通过云基础设施运营?

Cloudflare 有助于保护和管理任何类型的云部署。我们的网络是连接最终用户与客户产品或服务的云基础设施的桥梁。客户可以通过单个仪表板管理其所有云部署的性能安全性DNS 和其他 Cloudflare 产品。Cloudflare 提供 Web Application Firewall(Web 应用程序防火墙),保护 Internet 属性免遭漏洞攻击。Cloudflare 还使企业能够将 FaaS(无服务器)服务模型轻松地整合到他们自己的云部署中。

请在此处了解 SaaS 的 Cloudflare 解决方案

云与 Internet 的传统客户端-服务器模型 (client-server model) 有何不同?

The Internet has always been made up of servers, clients, and the infrastructure that connects them. Clients make requests of servers, and servers send responses. Cloud computing differs from this model in that cloud servers aren't just responding to requests — they're running programs and storing data on the client's behalf.

为什么将它称为“云”?

“云”最初是科技行业内的一个俗称。在 Internet 的早期,技术图通常用云朵来表示组成 Internet 的服务器和网络基础设施。随着越来越多的计算进程迁移到 Internet 中的这种“服务器和基础设施”部分,人们开始将“迁移到云”作为表达计算进程发生位置的一种简写方式。如今,“云”已成为这种计算方式广为接受的代名词。

那么,容器呢?容器是 IaaS、PaaS、SaaS 或 FaaS 吗?

与虚拟机类似,容器是一种云虚拟技术。容器是 PaaS(平台即服务)云模型的一部分。容器虚拟化发生的位置要比虚拟机中发生虚拟化的位置高一个抽象层,在操作系统级别而不是内核级别(内核是操作系统的基础,并与计算机的硬件进行交互)。每台虚拟机都有自己的操作系统内核,但是同一台计算机上的容器共享同一个内核。