Function App HTTP Server Errors

Question

I am running numerous function apps on Windows Consumption plan. Over the last few weeks I am seeing a lot of HTTP Server Errors. When I go to diagnose and solve problems there are lots of application stop events and I am seeing errors such as:

[Tag=''] Process reporting unhealthy: Unhealthy. Health check entries are {"azure.functions.web_host.lifecycle":{"status":"Healthy","description":null},"azure.functions.script_host.lifecycle":{"status":"Unhealthy","description":"No script host available","errorCode":"NoScriptHost"},"azure.functions.webjobs.storage":{"status":"Healthy","description":null}}

I am running .net10 apps. I am not sure if this issue coincides with the upgrade to .net10, but if anyone can support and help fix this issue as I am seeing it across multiple apps.

Answer 1

Hello @Chris Gray,

To resolve the “NoScriptHost” error, First, ensure that your function app is configured to use the correct version of the .NET runtime by checking the application settings in the Azure portal.

Next, review the logs for any errors that might indicate what is preventing the script host from starting. If the issue persists, consider temporarily rolling back to a previous version of .NET to see if that resolves the problem, which can help confirm if the upgrade is indeed the cause of the issue.

Resolve "Function App Down or Reporting Errors" issues

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Answer 2

Hi @Chris Gray

Thanks for reaching out to Microsoft Q&A.

Here’s a step-by-step approach to troubleshoot HTTP Server Errors across your function apps:

As discussed on Private chat, you are working with the MS support directly for this issue.

You can refer the steps here to troubleshoot your issue:

First, confirm that your Azure Functions homepage is accessible. If you haven’t disabled it, you should be able to see a page indicating that the Functions host is running.

1. Since you're using .NET 10, ensure that your apps are targeting the correct Azure Functions runtime version. You can refer to this document on changing the version of apps in Azure.
2. Review Logs and Metrics:
   • Check the Kudu SCM website for errors. Look through the event log at $HOME\Logfiles\Eventlog.xml for any indication of what's causing the unhealthy state.
   • Enable Application Insights if you haven’t already and check for any critical errors logged there. Here’s how to enable Application Insights.
3. Make sure that your storage account settings are configured properly. If you’re operating under the Consumption or Elastic Premium plan, follow this documentation to ensure everything is set up correctly.
4. It's worth noting that Azure Functions runtime limits could be causing some of your HTTP errors (like 502 or 429). Reviewing the documentation on function scale issues may give you insight into how to manage demand on your functions more effectively.
5. As a temporary measure, consider setting fileLoggingMode to "always" in your host.json to collect more detailed logs, then switch it back to "debugOnly" for production here’s the logging guide.

Lastly, ensure there are no long-running or resource-intensive operations within your functions that might be hanging things up or causing crashes.

Hope this helps!

References:

• Function App Down or Reporting Errors
• Azure Monitor Documentation
• Application Insights Documentation
• Storage Account Configuration
• HTTP Functions Scaling