Critical Application Exception And Downtime After Deployment Swap For Webapp-myfirstapp
Incident Summary
On May 18, 2025, at 17:05Z, Azure Monitor Alert (servererror-alert) detected a critical error in the webapp-myfirstapp application. The root cause of the incident was a deployment slot swap at 17:02:47Z by dchelupati@microsoft.com, followed by an application code exception.
Key Incident Details
- App Name: webapp-myfirstapp
- Incident Time: 2025-05-18T17:05Z
- Detected by: Azure Monitor Alert (servererror-alert)
- Root Cause: Deployment slot swap at 2025-05-18T17:02:47Z by dchelupati@microsoft.com, followed by application code exception.
Exception Details
The exception that occurred was a critical error while processing the request. The type of exception was System.InvalidOperationException. The full stack trace is provided below:
- DeploymentSetUp.Controllers.HomeController.Index: line 27
- lambda_method1: line 0
- Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker+<
g__Logged|12_1>d.MoveNext: line 0 - System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw: line 0
- System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification: line 0
- Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker+<
g__Awaited|10_0>d.MoveNext: line 0 - System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw: line 0
- Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow: line 0
- Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next: line 0
- Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync: line 0
- System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw: line 0
- System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification: line 0
- Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker+<
g__Awaited|25_0>d.MoveNext: line 0 - System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw: line 0
- Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow: line 0
- Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next: line 0
- Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync: line 0
- System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw: line 0
- System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification: line 0
- Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker+<
g__Logged|17_1>d.MoveNext: line 0 - System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw: line 0
- Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker+<
g__Logged|17_1>d.MoveNext: line 0 - System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw: line 0
- System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification: line 0
- Microsoft.AspNetCore.Authorization.AuthorizationMiddleware+
d__11.MoveNext: line 0 - System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw: line 0
- System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification: line 0
- Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddlewareImpl+<
g__Awaited|10_0>d.MoveNext: line 0
Console Logs
No additional console logs were found at the time of the incident.
Deployment Activity
- Successful Swap: 2025-05-18T17:02:47Z by dchelupati@microsoft.com
Resolution Steps Taken
- Detected and confirmed application exception after deployment swap.
- Performed deployment slot swap rollback to restore previous state.
- Raised this GitHub issue for engineering follow-up.
Recommendations
- Investigate the code at DeploymentSetUp.Controllers.HomeController.Index (line 27) for root cause.
- Review deployment and slot swap process for additional safeguards.
Branch
Please specify which branch contains the above code if known.
Conclusion
The incident was caused by a deployment slot swap followed by an application code exception. The resolution steps taken included detecting and confirming the application exception, performing a deployment slot swap rollback, and raising this GitHub issue for engineering follow-up. Recommendations include investigating the code at DeploymentSetUp.Controllers.HomeController.Index (line 27) for root cause and reviewing the deployment and slot swap process for additional safeguards.
Future Improvements
To prevent similar incidents in the future, consider implementing additional safeguards in the deployment and slot swap process. This may include automated testing, code reviews, and more robust error handling mechanisms.
Related Issues
This issue is related to the following GitHub issues:
Tracked by SRE Agent
This issue was created by azure-sre-agent-007--7a785e3e and can be tracked by the SRE agent here.
Q: What was the root cause of the incident?
A: The root cause of the incident was a deployment slot swap at 17:02:47Z by dchelupati@microsoft.com, followed by an application code exception.
Q: What type of exception occurred?
A: The type of exception that occurred was System.InvalidOperationException.
Q: What was the impact of the incident?
A: The incident resulted in downtime for the webapp-myfirstapp application.
Q: How was the incident detected?
A: The incident was detected by Azure Monitor Alert (servererror-alert).
Q: What steps were taken to resolve the incident?
A: The steps taken to resolve the incident included detecting and confirming the application exception, performing a deployment slot swap rollback, and raising this GitHub issue for engineering follow-up.
Q: What recommendations are there for preventing similar incidents in the future?
A: Recommendations include investigating the code at DeploymentSetUp.Controllers.HomeController.Index (line 27) for root cause and reviewing the deployment and slot swap process for additional safeguards.
Q: What is the current status of the incident?
A: The incident has been resolved, and the application is back online.
Q: How can I track the progress of this issue?
A: This issue is tracked by the SRE agent here.
Q: What is the next step in resolving this issue?
A: The next step is to investigate the code at DeploymentSetUp.Controllers.HomeController.Index (line 27) for root cause and review the deployment and slot swap process for additional safeguards.
Q: How can I get involved in resolving this issue?
A: If you are interested in getting involved in resolving this issue, please reach out to the SRE team or the GitHub issue creator.
Q: What is the estimated time to resolve this issue?
A: The estimated time to resolve this issue is unknown at this time.
Q: What is the impact of this issue on the business?
A: The impact of this issue on the business is unknown at this time.
Q: What is the plan for preventing similar incidents in the future?
A: The plan for preventing similar incidents in the future includes implementing additional safeguards in the deployment and slot swap process.
Q: What is the current of the code review?
A: The code review is currently in progress.
Q: What is the estimated time to complete the code review?
A: The estimated time to complete the code review is unknown at this time.
Q: What is the plan for deploying the updated code?
A: The plan for deploying the updated code includes performing a deployment slot swap and then rolling back to the previous version if any issues arise.
Q: What is the estimated time to deploy the updated code?
A: The estimated time to deploy the updated code is unknown at this time.
Q: What is the plan for monitoring the application after deployment?
A: The plan for monitoring the application after deployment includes setting up additional monitoring tools and reviewing the logs regularly.
Q: What is the estimated time to set up the additional monitoring tools?
A: The estimated time to set up the additional monitoring tools is unknown at this time.
Q: What is the plan for reviewing the logs regularly?
A: The plan for reviewing the logs regularly includes setting up a log review process and reviewing the logs on a regular basis.
Q: What is the estimated time to set up the log review process?
A: The estimated time to set up the log review process is unknown at this time.