You face an issue with your Azure App Service, running under an App Service Plan and having dependencies possibly to other App Services and Azure resources. Each possible issue can manifest under different circumstances, in different configurations and under different application loads and application dependencies. It is important that you first perform extensive testing to isolate the scope of your App Service issue and be able to replicate your issue in a consistent manner before proceeding with any further troubleshooting.
The general types of App Service issues can be classified into the following categories:
- App Service optimal configuration, including availability and scaling configuration
- App Service CPU, memory, networking and application code performance
- TLS certificates or custom domain configuration
This article provides high level guidance on how to diagnose and solve problems in Azure App Service.
You should also review the article in the “Sources” section of this KB article for more Azure App Service troubleshooting guidance.
You can make use of the Azure portal “Diagnose and solve problems” section under your App Service in question. This provides a handful of troubleshooting tools available as summarized in the following screenshot. These tools can be integrated to App Service Application Insights to retrieve more granular information at the application level. Also each analysis tool provides a documented step-by-step approach in some cases to further assist you in troubleshooting your issue(s).
Run the App Service risk assessment tools for an evaluation of your App Service availability, performance and optimal configuration.
One example is the best practice tool for App Service plan scaling analysis, as shown below.
Run the performance related analysis tools to evaluate App Service CPU, memory, networking and application code performance and identify potential bottlenecks.
For App Service performance issue troubleshooting, also refer to the following articles:
Run the SSL and domains configuration analysis tools to discover any issues related to the TLS certificates or custom domain configuration.
Run the Configuration and Management analysis tools to discover any other further configuration related issues in your App Service.
Make use of the available Azure App Service diagnostic tools, as shown below to take traces and further analyze using your own tools (such as wireshark for network traces) or share with Microsoft Support team for further analysis. The most commonly used diagnostic tools for tracing in App Service are the .NET profiler, the network trace tool and the network troubleshooter.
Bear in mind that some of the App Service telemetry data may only be visible to the Microsoft Azure support team. Also some of the traces taken via the portal may be in file formats only readable internally by Microsoft support.