Frequent random App pool shutdown with ApplicationShutdownReason.ConfigurationChange and no obvious config changes present on server

Question

Our application running IIS 8 server has started to shut down randomly and frequently with ApplicationShutdownReason.ConfigurationChange events being fired.

After investigation, we found that no changes have been made to the web.config corresponding to the ApplicationShutdownReason.ConfigurationChange events.

Is there some way that we could further determine precisely what changes are causing the ApplicationShutdownReason.ConfigurationChange event?

Answer 1

Hi @dalste

The problem you are experiencing may be a Microsoft bug. You can try using Hotfix to see if it fixes the problem. Refer to: https://support.microsoft.com/en-us/topic/unexpected-asp-net-application-shutdown-after-many-app-data-file-changes-occur-on-a-server-that-is-running-windows-server-2012-r2-6316ddb2-abab-e172-1f0c-cec9dc05265c

In addition, "ConfigurationChange" does not just include web.config. It means that a change was made to the application-level configuration file. You can monitor IIS configuration change using Event Logs in SAM:

1. Go to Start > Event Viewer.
2. Expand Applications and Services Logs > Microsoft > Windows > IIS-Configuration > Operational > Enable Log.
3. Close Event Viewer to Finish.

Source: https://thwack.solarwinds.com/product-forums/server-application-monitor-sam/f/forum/15259/how-to-monitor-iis-configuration-change-using-event-logs-in-sam

If there are any other questions, just let me know directly. It's my pleasure to help you.

Best Regard,

TengFei Xie

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Answer 2

Yes, there are a few steps you can take to further investigate what changes are causing the ApplicationShutdownReason.ConfigurationChange events:

1. Review the event logs: Check the Windows event logs for any errors or warnings related to IIS, ASP.NET, or your application. These logs may provide additional details about the reason for the configuration changes.
2. Enable detailed logging: Enable detailed logging in IIS and ASP.NET. This will log every request and response, including any errors or warnings. You can then review these logs to determine if there is a pattern to the configuration changes.
3. Use a configuration monitoring tool: There are various tools available that can monitor changes to configuration files and alert you when a change is detected. These tools can help you pinpoint which changes are causing the ApplicationShutdownReason.ConfigurationChange events.
4. Debug the application: You can attach a debugger to your application and set breakpoints in the Application_End method of your Global.asax file. This will allow you to step through the code and determine the exact point at which the application is shutting down.
5. Check for external factors: It's possible that external factors, such as hardware failures or network issues, are causing the configuration changes. Check for any issues with the server hardware or network connectivity.

By following these steps, you should be able to further determine precisely what changes are causing the ApplicationShutdownReason.ConfigurationChange events.