Container app shutting down almost immediately

Hello @Jesse Kela,

The issue with your .NET application shutting down quickly could stem from several factors. It might be caused by an application crash due to unhandled exceptions or errors, check the logs for any relevant messages before shutdown. Health probe failures could also be a reason, as Azure may mark the app as unhealthy if it doesn't respond correctly. Ensure the app is listening on the right port and health checks are configured properly.

Additionally, resource constraints, like high memory or CPU usage, could cause the app to be killed by the runtime, so look for any out-of-memory errors in the logs. Scaling issues, especially with fetching external metrics, may impact the app’s ability to scale and lead to shutdowns. Verify that the metrics API is set up correctly. To diagnose further, try running the app locally using Docker to see if the issue is Azure-specific or app-related.

For further clarification, please refer to the following documentations:

Troubleshoot start failures in Azure Container Apps

Troubleshoot container create failures in Azure Container Apps

I hope this helps resolve your issue. Feel free to reach out if you have further concerns.

No application exceptions. Same code deployed in seemingly identical environment. Same resources given. Ports are identical. Health probes are identical as far as I understand but I'm not exactly sure which all places I need to check. Internet gateway backend health returns 503 but is it symptom or cause of the above mentioned issues.

Hello @Jesse Kela,
The 503 error in the backend health check could be a symptom of the issue, indicating the backend is unavailable. Double-check your health probe settings. Ensure the probe points to a valid endpoint and returns a 200 OK status. If the probe returns errors, Azure might mark the app as unhealthy and shut it down.

The issue with fetching external metrics (s1-upstream_rq_total)could affect scaling, so verify that the metrics API is set up correctly. Try manually scaling the app to see if the problem persists.

Lastly, review the application logs for startup issues and ensure the app is not exceeding memory or CPU limits, which could cause it to be killed by the runtime.

Hello @Jesse Kela,

Just checking in to see if above information was helpful. If you have any further updates on this issue, please feel free to post back.

I had external service connectivity issue that was required in startup. Probably due longer connection timeout than application gateway health check was, the container app made application shutdown and never ran into any actual errors. Solved the networking issue and container is now up and running healthy.