什么是基础设施即服务 (IaaS)？

IaaS stands for Infrastructure as a Service. NIST (SP 800-145) defines it as provisioning processing, storage, and networks to run any software, which can include operating systems. Think of it as renting the basics of a computer system – servers, storage, and networking – from a cloud provider rather than buying and maintaining your own hardware.

可以将其理解为 租用一个设备齐全的厨房，而不是自己建造一个。

IaaS, PaaS, and SaaS are the three main types of cloud computing services:

• IaaS（基础设施即服务）： 您租用基础资源（虚拟服务器、存储、网络），然后在这些资源之上构建您的应用程序和系统。
• PaaS（平台即服务）： 一个完整的平台，提供用于开发、部署和管理应用程序的工具和服务。
• SaaS（软件即服务）： 通过互联网使用的软件应用程序，无需自行安装或维护。

IaaS 和 SaaS 之间的区别在于您拥有的控制权和责任的大小。使用 IaaS，您拥有更多的控制权和责任，而使用 SaaS，您拥有的则较少。

IaaS 就像租一块土地并建造房屋。PaaS 就像租一套公寓。SaaS 就像租一套带家具的公寓。

IaaS 提供以下服务：

• 成本： Direct hardware investments are not a prerequisite, and maintenance expenditures typically manifest at a lower degree. IaaS is usually billed pay-as-you-go for the resources you use.
• 灵活性： The operating system, software, and configurations can be specified by the user.
• 可用性： Redundant infrastructure correlates with the availability of data and applications.
• 可扩展性： It involves modifying resource levels to align with shifts in demand.

这使得 IaaS 成为企业无需管理自身基础设施即可访问计算资源的一种方式。 Under the hood, IaaS relies on virtualization: the provider creates virtual versions of its servers, storage, and networks that behave like physical ones (AWS).

IaaS 适用于： 工作负载波动较大的企业、初创公司以及需要部署应用程序或测试环境的组织。

IaaS 被企业和个人用于：

• 初创公司： 在无需投资基础设施的情况下启动和扩展
• 企业： 实现 IT 基础设施现代化并降低成本。
• 开发者： 设置开发和测试环境
• Anyone 谁 needs access to computing resources.

IaaS is a partly managed service: in NIST’s definition (SP 800-145), you control the operating systems, storage, and deployed applications, but not the underlying cloud infrastructure (NIST). This gives you more control but also requires more technical expertise.

If you lack the technical skills or resources to manage your own infrastructure, consider PaaS or SaaS solutions, which offer a higher level of abstraction. One provider can offer both models: on Azure, Microsoft describes IaaS as provisioning virtual machines, while App Service and Container Apps are its platform as a service (PaaS) offerings (Microsoft Learn). But if you need control over your environment and want to customize it, IaaS is recommended.