Webapp is in Ready state but running and getting application error

Question

The app is marked as Ready, but I’m still getting an application error. When I check the logs, the instance does not appear in the dropdown. What could be causing this?

Answer 1

Hi @Nicole W

Thank you for sharing the error details this helps clarify the root cause.

On Azure App Service for Linux, the App Service platform may mark the app as “Ready” once the container host is allocated, even if the application process inside the container hasn't fully started or is idle/hung.

In this situation:

• The container instance was not fully attached or initialized, which led to:
• Log Stream being unable to detect a running instance
• Initial failures with SSH and runtime operations
• When you connected via SSH, it triggered container initialization and instance attachment, resulting in:
• The instance becoming visible in Log Stream
• The application responding as expected

This points to a temporary container startup or instance registration issue, rather than a problem with the application code.

Microsoft has confirmed that:

• Log streaming and diagnostics require a running instance
• SSH access is possible only when the container is fully started and running 

Reference : https://learn.microsoft.com/en-us/azure/app-service/configure-linux-open-ssh-session?pivots=container-linux

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