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Role Environment Variables in Full IIS Web Role and in HWC Web Role

Role Environment Variables in Full IIS Web Role and in HWC Web Role

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When you will use the following code in Page_Load function of default.aspx:

                String sRootPath = Environment.GetEnvironmentVariable("RoleRoot");


You will see different results depend on Full IIS Web Role and HWC as below:

Full IIS Web Role  -         sRootPath =       NULL

HWC Web Role -             sRootPath =       E:


This is because:

-           In Full IIS configuration, the Web Role is running in WaIISHost.exe process however to Web Site is running in w3wp.exe.

-           In HWC web role, both the role and web site is running in WaWebHost.exe process.  

-           With Full IIS the web site process is not only a different appdomain but a different process launched by a different service.

-           Because of it the situation becomes complex to pass the role environment variables to web site.

-           You can write code to pass this data via the registry or file system.  

-           You can read service configuration settings using the RoleEnvironment.GetConfigurationSettings. 

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  • Hi Avkash

    Thanks for this post.

    RoleEnvironment.GetConfigurationSettings() is an unknown method - what version of the sdk is this?

  • It’s been a great pleasure to thank you for this informative article. I will always recommend your article and refer to my friend too for the same.

  • When I am using a WebRole deployed to Azure, I can use RoleEnvironment in my RoleEntryPoint as well as my website (running in the cloud service in a w3wp). However if I add another Site this site cannot access RoleEnvironment. Why is it that one website can, but another cannot? This is with SDK 2.4


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