Windows Azure Websites, Web Roles, and VMs: When to use which?
The June 7th update to Windows Azure introduced two new services (Windows Azure Websites and persistent VMs) that beg the question “When should I use a Windows Azure Website vs. a Web Role vs. a VM?” That’s exactly the question I’ll try to help you answer in this post. (I say “help you answer” because there is no simple, clear-cut answer in all cases. What I’ll try to do here is give you enough information to help you make an informed decision.)
Note: The information in this post has been turned into official documentation by the Windows Azure content team. For the most up to date information, see Windows Azure Web Sites, Cloud Services, and VMs: When to use which? on WindowsAzure.com.
The following table should give you some idea of what each option is ideal for:
| Windows Azure Web Sites are ideal for… | Windows Azure Web Roles are ideal for... | Windows Azure Virtual Machines are ideal for... |
Modern Web Apps Applications that consist of client-side markup and scripting and/or server-side scripting and a database. You can scale out or up as needed. Also the web tier of multi-tier applications. |
Multi-tier Applications Applications that are composed of multiple tiers, each of which can be scaled independently (i.e. asynchronous background processing, like order processing) using both Web and Worker Roles. Note: Web Sites can also be used for the web tier. |
Server Applications Existing applications that leverage SQL Server, MySQL, MongoDB, Sharepoint Server, etc. |
Continuous Development Deploy directly from your source code repository using Git or Team Foundation Service. |
Apps that require advanced administration Applications that require admin access, remote desktop access, or running code with elevated privileges. |
Existing line-of-business apps Choose an image from the gallery or upload your own VHD. |
Popular Open Source Apps Launch a site with a few clicks using apps like WordPress, Joomla!, and Drupal. |
Apps that require advanced networking Applications that require network isolation with Windows Azure Connect or Windows Azure Virtual Network. |
Windows or Linux Support for Windows Server and community/commercial versions of Linux. Connect VMs with Cloud Services to take advantage of PaaS services. |
Actually, I think the use cases for VMs are wide open. You can use them for just about anything you could imagine using a VM for. The tougher distinction (and decision) is between Web Sites and Web Roles. The following table should give you some idea of what Windows Azure features are available in Web Sites and Web Roles:
Feature |
|
|
Access to services like Caching, Service Bus, Storage, SQL Azure Database |
Yes |
Yes |
Support for ASP.NET, classic ASP, Node.js, PHP |
Yes |
Yes |
Shared content and configuration |
Yes |
No |
Deploy code with GIT, FTP |
Yes |
No |
Near-instant deployment |
Yes |
No |
Integrated MySQL-as-a-service support |
Yes |
Yes* |
Multiple deployment environments (production and staging) |
No |
Yes |
Network isolation |
No |
Yes |
Remote desktop access to servers |
No |
Yes |
Ability to run programs with elevated permissions |
No |
Yes |
Ability to define/execute start-up tasks |
No |
Yes |
Ability to use unsupported frameworks or libraries |
No |
Yes |
Support for Windows Azure Connect/ Windows Azure Network |
No |
Yes |
* Web or Worker Roles can integrate MySQL-as-a-service through ClearDB's offerings, but not as part of the Management Portal workflow.
As I said earlier, it’s impossible to provide a definitive answer to the question of which option you should use (Web Sites, Web Roles, or VMs). It really does depend on your application. With that said, I hope the information in the tables above helps you decide what is right for your application. Of course, if you have any questions and/or feedback, let us know in the comments.
Thanks!
-Brian