What's behind an App Service (Web App)

Andrew HB 321 Reputation points
2021-04-15T11:00:07.98+00:00

Just looking to migrate a legacy ASP.NET 4.5.2 application to Web App's and it doesn't seem to be honouring the web.config file setup for things such as default document etc. we also have lots of inline HTTP modules etc.

Are web apps just completely different to hosting in IIS?

Azure App Service
Azure App Service
Azure App Service is a service used to create and deploy scalable, mission-critical web apps.
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  1. Michael Taylor 45,996 Reputation points
    2021-04-15T14:01:08.227+00:00

    An App Service is literally just a VM running IIS. Everything is the same provided you configured the app service to actually run .NET which is an option when you set up the service. IIS is running in the background, your site is deployed to a specific folder and IIS is adjusted to host it just like on a normal IIS instance.

    My gut instinct is that your configuration isn't correct. However I should also point out that app services are configurable via the slot settings that your site is hosted under so it is also possible that you have overridden the configuration settings. Go to the Azure portal and then to your app service. Under Settings\Configuration go to the Default Documents tab. This is going to override your config settings I believe but it is possible it might pull from your config to get the list. I've never bothered to look.

    Use Kudu to view your site's file system and ensure the web.config is properly deployed. Under the app service in the portal go to Development Tools\Advanced Tools. Click Go to bring up Kudu. Personally I then use the nav at the top to go to Debug console\Powershell. You can see the file system and make changes if needed.

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  1. SUNOJ KUMAR YELURU 13,901 Reputation points MVP
    2021-04-15T12:33:46.903+00:00

    Hi @Andrew HB

    Azure App Service is an HTTP-based service for hosting web applications, REST APIs, and mobile back ends. You can develop in your favorite language, be it .NET, .NET Core, Java, Ruby, Node.js, PHP, or Python. Applications run and scale with ease on both Windows and Linux-based environments.

    Migrate .NET web apps with ease
    Bring your web apps to the cloud with minimal or no code changes using the Azure App Service Migration Assistant - a free and simple tool to automatically migrate .NET web applications from on-premises to the cloud.

    Migrate in three easy steps
    Quickly assess your website for migration by running a scan of its public URL.
    Download the Migration Assistant to run readiness checks.
    Migrate your web app.
    Azure App Service migration assistant

    Configure an ASP.NET app for Azure App Service

    If the Answer is helpful, please click Accept Answer and up-vote, this can be beneficial to other community members.

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  2. Andrew HB 321 Reputation points
    2021-04-15T12:43:18.65+00:00

    Thank you for your response, our apps don't migrate automatically, not that I ever thought they would LOL!

    I have deployed simple ASP.NET .NET Framework application to a Web App and although it displays things like the default document aren't working. I assume this is because the App Service is not using the web.config in the same way that a Cloud Service (Extended Support) service does as that just has a VM with IIS installed upon it.

    I was just checking to see if there was some magic switch that I had missed where I can tell the app service to behave in the same manner as my Cloud Service i.e. use the web.config

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  3. Andrew HB 321 Reputation points
    2021-04-15T14:09:23.787+00:00

    Haha! Thank you @Michael Taylor

    I chose ASP.NET 4.8 when I deployed, should I have chosen .NET I seem to remember that being a separate option in the dropdown?