Can Application Insights be used with a Linux Web App running .NET Core 3 runtime?

Code-less enablement of Application Insights for Asp.Net core is not yet supported for linux. You need to do code-based enablement, which involves installing SDK nugets to your project as documented below: https://docs.microsoft.com/en-us/azure/azure-monitor/app/asp-net-core

According to the docs, yes!

Supported scenarios The Application Insights SDK for ASP.NET Core can monitor your applications no matter where or how they run. If your application is running and has network connectivity to Azure, telemetry can be collected. Application Insights monitoring is supported everywhere .NET Core is supported. Support covers:

Operating system: Windows, Linux, or Mac. Hosting method: In process or out of process. Deployment method: Framework dependent or self-contained. Web server: IIS (Internet Information Server) or Kestrel. Hosting platform: The Web Apps feature of Azure App Service, Azure VM, Docker, Azure Kubernetes Service (AKS), and so on. .NET Core Runtime version: 1.XX, 2.XX, or 3.XX IDE: Visual Studio, VS Code, or command line. Note

If you are using ASP.NET Core 3.0 along with Application Insights, please use the 2.8.0 version or higher. This is the only version that supports ASP.NET Core 3.0.

Auto-instrumentation for Application Insights for .NET Core apps is a high priority and work is planned to support the functionality. Stay tuned! Your feedback and patience are greatly appreciated! :)