web角色是承载多个网站的虚拟机

Azure网站、Web worker和虚拟机是Windows Azure上可用的三种不同的计算方法。他们在控制和责任的水平上有所不同:

Azure网站有最低级别的控制，但你不关心保持健康的虚拟机和IIS，因为Azure的东西为你做这些 Web角色给你更多的控制(流量管理器，远程桌面)，但更多的管理是可能的，这意味着你可以通过远程桌面破坏一些东西 虚拟机让您完全控制VM，因此需要最大的管理工作。

没有最好的选择，因为这取决于你需要什么样的控制级别，你需要什么特性，以及你希望留给Azure哪些东西来维护。这是一个大话题。

请阅读这篇文章，了解更多信息，做出更明智的选择:

http://www.windowsazure.com/en-us/documentation/articles/choose-web-site-cloud-service-vm/ http://davidpallmann.blogspot.com/2012/06/reintroducing-windows-azure-part-2.html

这可以归结为易用性和功能之间的权衡。

我刚刚在http://robdmoore.id.au/blog/2012/06/09/windows-azure-web-sites-vs-web-roles/上发表了一篇关于这个主题的全面博客文章。

我的结论摘录如下:如果你需要巨大的规模，SSL，亚洲或美国西部的数据中心，一个非标准配置(IIS，端口，诊断，安全证书或启动脚本)，RDP或具有成本效益的工作者角色(结合你的Web角色)，那么你现在将不得不坚持使用Web角色。

否则，网站是一个很好的选择!

Web角色提供了Web应用程序(以前的Web站点)之外的几个功能:

Ability to run elevated startup scripts to install apps, modify registry settings, install performance counters, fine-tune IIS, etc. Ability to split an app up into tiers (maybe Web Role for front end, Worker Role for backend processing) and scale independently Ability to RDP into your VM for debugging purposes Network isolation Dedicated virtual IP address, which allows web role instances in a cloud service to access IP-restricted Virtual Machines ACL-restricted endpoints (added in Azure SDK 2.3, April 2014) Support for any TCP/UDP ports (Web Sites are restricted to TCP 80/443)

Web应用程序比Web角色有优势:

Near-instant deployment with deployment history / rollbacks Visual Studio Online, github, local git, ftp, CodePlex, DropBox, BitBucket deployment support Ability to roll out one of numerous CMS's and frameworks, (like WordPress, Joomla, Django, MediaWiki, etc.) Use of SQL Database or MySQL Simple and fast to scale from free tier to shared tier to dedicated tier Web Jobs Backups of Web Site content Built-in web-based debugging tools (simple cmd/powershell debug console, process explorer, diagnostic tools like log streaming, etc.)

随着2014年4月和2014年9月的推出，现在有一些Web应用程序和Web角色(以及工作者角色)共同的特性，包括:

登台+生产槽 通配符DNS, SSL证书 Visual Studio集成 流量管理器支持 虚拟网络支持

以下是我从网站图库选择表单中截取的截图:

我认为Web应用程序是快速启动和运行的好方法，你可以从共享资源转移到预留资源。一旦你不再局限于此，你就可以升级到Web角色，并根据需要进行扩展。

我发现的另外两件事是为自定义域站点获取SSL的成本和多租户配置。

对于网站，你需要在标准实例的基础上每月支付(小实例是最便宜的选择)。这意味着为了获得自定义域https将花费你~70/月的小实例加上~41/月的SSL支持所有浏览器。

对于WebRole，您可以免费获得XS实例并添加自己的SSL，这意味着每月约15美元 你有一个自定义的SSL域。

对于多租户网站检查 多租户Azure动态通配符CName

Azure Web Sites enables you to build highly scalable web sites quickly on Azure. You can use the Azure Portal or the command-line tools to set up a web site with popular languages such as .NET, PHP, Node.js, and Python. Supported frameworks are already deployed and do not require more installation steps. The Azure Web Sites gallery contains many third-party applications, such as Drupal and WordPress as well as development frameworks such as Django and CakePHP. After creating a site, you can either migrate an existing web site or build a completely new web site. Web Sites eliminates the need to manage the physical hardware, and it also provides several scaling options. You can move from a shared multi-tenant model to a standard mode where dedicated machines service incoming traffic. Web Sites also enable you to integrate with other Azure services, such as SQL Database, Service Bus, and Storage. Using the Azure WebJobs SDK preview, you can add background processing. In summary, Azure Web Sites make it easier to focus on application development by supporting a wide range of languages, open source applications, and deployment methodologies (FTP, Git, Web Deploy, or TFS). If you don’t have specialized requirements that require Cloud Services or Virtual Machines, an Azure Web Site is most likely the best choice.

Cloud Services enable you to create highly-available, scalable web applications in a rich Platform as a Service (PaaS) environment. Unlike Web Sites, a cloud service is created first in a development environment, such as Visual Studio, before being deployed to Azure. Frameworks, such as PHP, require custom deployment steps or tasks that install the framework on role startup. The main advantage of Cloud Services is the ability to support more complex multitier architectures. A single cloud service could consist of a frontend web role and one or more worker roles. Each tier can be scaled independently. There is also an increased level of control over your web application infrastructure. For example, you can remote desktop onto the machines that are running the role instances. You can also script more advanced IIS and machine configuration changes that run at role startup, including tasks that require administrator control.

Virtual Machines enable you to run web applications on virtual machines in Azure. This capability is also known as Infrastructure as a Service (IaaS). Create new Windows Server or Linux machines through the portal, or upload an existing virtual machine image. Virtual Machines give you the most control over the operating system, configuration, and installed software and services. This is a good option for quickly migrating complex on-premises web applications to the cloud, because the machines can be moved as a whole. With Virtual Networks, you can also connect these virtual machines to on-premises corporate networks. As with Cloud Services, you have remote access to these machines and the ability to perform configuration changes at the administrative level. However, unlike Web Sites and Cloud Services, you must manage your virtual machine images and application architecture completely at the infrastructure level. One basic example is that you have to apply your own patches to the operating system.

从这个链接可以看到更新的和全面的比较:http://azure.microsoft.com/en-us/documentation/articles/choose-web-site-cloud-service-vm/