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Services and cloud services
Learn Xaas cloud services might begin to understand the service.
"Services" in essence is a lease, the resource occupancy scheme it is "for our own use" rather than "all for me", resource consumption patterns rather than a pay-fixed expenses.
In life, for rental services is not commonly used items for a long time, small graduation dresses, DIY tools, large equipment and buildings, can lease. Now sharing economy set off a hot rental service, great "Everything as a service" trend: Housing has Airbnb, travel there by bit, thanks to Morocco, even cooking, beauty and so have the appropriate vendor without and then their own hands. For service providers, the improving product usage pricing model has brought long-term return on investment had "one shot deal" compared to the individual products is higher; for buyers in terms of service, pay-as mode not only reduces the costs and risks, but also save maintenance costs.
In the operation of enterprises, the service can also be purchased on demand commonly known as "outsourcing." Such as recruitment processes, marketing, strategic consulting and other work requirements, the company has a corresponding package them as a service provided to the customer by professionals. With the Internet, mobile Internet and cloud computing development, the business side of IT deployment is also available as a service provided by a specialized company:
The aforementioned and similar services, cloud computing services is a resource delivery and usage patterns, it refers to the resources needed by the network. The network provides resources is called "cloud", which seem to be unlimited and can be expanded at any time to acquire properties often been hailed as the same hydroelectric resources, you can buy and use as needed. Xaas is the description of the cloud services model, where X is the generation that X as a service Everything as a Service. The first is a Xass Iaas, namely Infrastructure as a service infrastructure as a service, and later developed Paas (Platform as a service platform as a service), Saas (Software as a service Software as a Service) and so on.
IaaS, PaaS SaaS 和
You can eat pizza with a story to illustrate the concept of image Iaas, Paas and Saas are:
If you want to eat pizza, then the optional program are the following:
1) do in their own homes, then you need from the kitchen and dining facilities to hydroelectric resources and then to all the items pizza ingredients.
2) fast-food pizza bought their own home, in which case you have a pizza prototype, but still need their own cooking.
3) The takeout pizza delivered at home, then you just need to have cutlery and dining table can be a dinner.
4) to pizzeria pizza, you can have nothing, bring your cell phone or money to eat enough.
You probably already know, the above four methods by analogy to the enterprise IT system that can correspond to local deployment On-Premises, Iaas infrastructure as a service, Paas Saas platform as a service and software as a service.
If the company decides to deploy local IT systems, it requires not only building a room, buy expensive servers and other hardware facilities, but also need to invest a very high operation and maintenance costs. In short, to build from the bottom of the network, storage, etc., to the operating system, to the development environment and application environment, companies need to burden themselves.
Iaas:
Iaas allows companies do not have their own burden hardware and other "infrastructure", but can be calculated to lease computing resources service provider basis Iaas power, storage, server, or network set up and so on. If local deployment, the company's IT department needed to satisfy peak demand to determine the infrastructure, but the only enterprise computing peak sometimes appears (such as Taobao need to cope with the maximum peak is probably two-eleven in the morning), as most of the rest time, the company's resources are idle, resulting in a substantial waste of IT resources. Iaas services are needed so that the company can increase or decrease the size of facilities, and on-demand pay. Typical Iaas service providers such as Amazon AWS (Amazon Web Service), users access computing infrastructure via Amazon Web interface, you can use a relatively low price lease computing power and storage resources, and the flexibility to expand or reduce related resources. Other common Iaas cloud server vendors as well as Ali, Tencent cloud servers.
Have:
Paas使得企业不必自己部署操作系统、代码运行的环境等“平台”，而是可以向Paas提供商租赁已经搭建好的各种底层开发系统平台，进而在此开发环境上直接部署程序。Paas无需下载或安装，服务提供商通过网络直接发送操作系统和相关服务。在这种模式中，有关硬件的维护和扩展都由服务提供商负责，开发人员只需根据接口进行应用程序开发即可。最典型的Paas服务提供商如谷歌App Engine（GAE），它支持多种编程语言编写的应用程序，提供详细的开发指南，以及一个完整的平台，开发者只需要为使用的资源付费，没有设置成本或日常费用，同时可以通过GAE提供的管理面板轻松对应用程序进行维护和升级。其它常见的Paas厂商还有微软Windows Azure，IBM Smart Cloud等。
Saas:
Saas使得厂商连应用程序也不必自己开发和管理，而是在需要某种软件的功能时，直接从Saas服务提供商那里租赁。Saas软件的特点是无需在本地安装，而是直接通过互联网从云端获取软件，并进行操作和数据存储，即把软件从客户端搬到云端。Saas服务的发展已有十多年之久，其厂商的典型代表是Salesforce.com的在线CRM系统（客户关系管理系统，用以协助企业了解及区别顾客，更好地进行销售和服务），企业用户的员工只要能上网，无论是电脑手机还是平板，都能访问销售云，随时随地管理自己的客户任务、电子邮件等，同时与自己的销售团队时刻保持沟通，获知最新信息，尽可能赢得交易。其它典型的Saas产品例如ERP系统（企业资源管理计划，用以将企业的生产、物流和财务等资源进行集成管理），OA系统（办公自动化，用于企业内部流程审批、协同办公、项目管理等）等。其它常见的Saas厂商还有Google Apps，苹果的icloud等。
Xaas一切皆服务
以上介绍了Saas，Paas和Iaas三个Xaas的典型例子，这三个结合起来使用，有时也被称作SPI模式，你大概已经理解，相对于传统的本地部署的企业IT模式，Xaas模式的好处是省钱省事，还能促进数据管理的行业标准化和信息共享。对于企业用户而言，随着技术的发展，传统IT模式需要经常为不同的项目更新服务器和网络设备，后续管理和维护的运营成本也很高。而新的Xaas模式允许用户根据需求租用云资源，用户不必购买拥有权，在后期还可按需灵活拓展。另外对于行业而言，基于云端的Xaas解决方案可以确保不同数据源上传后的格式统一，有利于建立起行业标准。
“Xaas”名词的兴起，意味着云服务已远不止渐渐成熟起来了的SPI模式，而是具有了更丰富的内涵，其它的例子比如：Daas数据即服务（Data），服务提供商对数据进行采集、清理、结构化和关系化，然后将数据以API接口的形式提供给用户使用，用户则无需考虑数据来源和收集问题；Naas网络即服务（Network），供应商部署网络基础设施，用户可以按需付费租赁诸如网络带宽等服务，例如我们熟知的VPN也被认为是Naas的一部分；Caas通信即服务（Communication），服务提供商将传统电信的能力如消息、语音、视频会议、通信协同等封装之后通过互联网提供给用户，即将电信能力作为服务对外提供；其它的Xaas云服务还有很多。