下面这些术语是什么意思?
SaaS PaaS IaaS吗?
现在有各种各样的云服务，比如亚马逊的EC2和AWS、Apache Hadoop、微软Azure和许多其他云服务。它们分别属于哪一类，为什么?
当前回答
正如所有人都很好地解释了云计算模型。所以我想要描绘出这三种模式IaaS, PaaS, SaaS w.r.t. AWS服务和它们的消费者。
其他回答
正如所有人都很好地解释了云计算模型。所以我想要描绘出这三种模式IaaS, PaaS, SaaS w.r.t. AWS服务和它们的消费者。
SaaS |
PaaS |
Iaas |
|---|---|---|
| Software-as-a-Service | Platform-as-a-Service | Infrastructure-as-a-Service |
| Ready to use infrastructure and software application that are centrally hosted and licensed on a subscription basis. | Ready to use environment. where customers build, test, run, and update apps quickly and inexpensively. | Provides on-demand access to physical computing resources, such as servers, storage, networking, and data center space without need to manage or operate. |
| Apps can be accessed over the internet on any device with a browser. | Cloud provider manages the entire platform. | Users can provision, test, and scale resources quickly. |
| Easy to add additional users and storage. | Additional compute, storage, and networking capacity can be purchased quickly and used immediately. | NA |
| Use Cases: Most personal or employee productivity applications (email, document management, online collaboration tools) | Use Cases: Migration of existing applications to the cloud, a hybrid cloud strategy | Use Cases: Backup/recovery of on-premises workloads, dev and test environments, customer facing websites, data storage and analytics |
云服务模型主要分为三类:
软件即服务(SaaS) 平台即服务(PaaS) 基础设施即服务(IaaS)
软件即服务(SaaS)
SaaS是一种为最终客户集中托管和管理的软件。它通常基于多租户架构(应用程序的单个版本用于所有客户)，并且通常通过每月或每年的订阅获得许可。
例子 Office 365、Dropbox、Dynamics CRM Online都是SaaS软件的完美例子，订阅者每月或每年支付订阅费，就可以获得Exchange即服务(在线和/或桌面Outlook)或Storage即服务(OneDrive和Dropbox)。
平台即服务(PaaS)
使用PaaS，您可以将应用程序部署到云服务供应商提供的应用程序托管环境(专为构建、测试和部署软件应用程序而设计)中。开发人员有多种方式来部署他们的应用程序，而不需要知道任何支持它的后台发生了什么。
例子 Azure应用程序服务和Azure云服务(Web和工作人员角色)中的Web应用程序功能是PaaS的一个例子。
基础设施即服务(IaaS)
IaaS云供应商运行和管理运行虚拟化软件的服务器场，使您能够创建运行在供应商基础设施上的虚拟机(运行Windows或Linux)，并在其上安装您想要的任何东西。开发人员不能控制硬件或虚拟化软件，但他们可以控制几乎所有其他的东西。事实上，与PaaS不同的是，您完全要对它负责。
参考文献
书:云架构:云计算服务模型(SaaS、PaaS和IaaS)的设计决策
SaaS: Software as a Service Cloud application services or “Software as a Service” (SaaS) are probably the most popular form of cloud computing and are easy to use. SaaS uses the Web to deliver applications that are managed by a third-party vendor and whose interface is accessed on the clients’ side. Most SaaS applications can be run directly from a Web browser, without any downloads or installations required. SaaS eliminates the need to install and run applications on individual computers. With SaaS, it’s easy for enterprises to streamline their maintenance and support, because everything can be managed by vendors: applications, runtime, data, middleware, O/S, virtualization, servers, storage, and networking. Gmail is one famous example of an SaaS mail provider.
PaaS: Platform as a Service The most complex of the three, cloud platform services or “Platform as a Service” (PaaS) deliver computational resources through a platform. What developers gain with PaaS is a framework they can build upon to develop or customize applications. PaaS makes the development, testing, and deployment of applications quick, simple, and cost-effective, eliminating the need to buy the underlying layers of hardware and software. One comparison between SaaS vs. PaaS has to do with what aspects must be managed by users, rather than providers: With PaaS, vendors still manage runtime, middleware, O/S, virtualization, servers, storage, and networking, but users manage applications and data.
IaaS: Infrastructure as a Service Cloud infrastructure services, known as “Infrastructure as a Service” (IaaS), deliver computer infrastructure (such as a platform virtualization environment), storage, and networking. Instead of having to purchase software, servers, or network equipment, users can buy these as a fully outsourced service that is usually billed according to the amount of resources consumed. Basically, in exchange for a rental fee, a third party allows you to install a virtual server on their IT infrastructure. Compared to SaaS and PaaS, IaaS users are responsible for managing more: applications, data, runtime, middleware, and O/S. Vendors still manage virtualization, servers, hard drives, storage, and networking. What users gain with IaaS is infrastructure on top of which they can install any required platforms. Users are responsible for updating these if new versions are released.
