Postmortem

Issue Summary:

Duration: June 14, 2023, 10:00 AM - June 14, 2023, 11:30 AM (UTC) Impact: The authentication service was down, resulting in users being unable to log in to the platform. Approximately 30% of users were affected by this issue. Root Cause: A misconfiguration in the load balancer caused incorrect routing of requests, leading to the authentication service becoming unresponsive.

Timeline:

• 10:00 AM: The issue was detected when the monitoring system triggered an alert for high latency in the authentication service.

• Actions Taken:

1. The engineering team was alerted about the issue.

2. The initial investigation focused on the authentication service and its underlying infrastructure.

3. Assumptions were made that the issue could be related to the database or network connectivity.

• Misleading Investigation:

1. Database investigation consumed significant time, but no issues were found.

2. Network connectivity was also thoroughly examined but was determined to be functioning properly.

• The incident was escalated to the infrastructure team for further assistance.

• 11:00 AM: The root cause was identified as a misconfiguration in the load balancer, causing requests to be sent to non-existent instances of the authentication service.

• Resolution:

1. The misconfiguration in the load balancer was corrected, ensuring proper routing of requests.

2. Load balancer health checks were enhanced to prevent similar misconfigurations in the future.

3. The authentication service was restarted to clear any residual issues.

4. User login functionality was fully restored by 11:30 AM.

Root Cause and Resolution:

The root cause of the issue was a misconfiguration in the load balancer, which resulted in incorrect routing of requests. This caused the authentication service to become unresponsive. The issue was fixed by correcting the load balancer configuration and ensuring proper routing of requests to the authentication service. Additionally, load balancer health checks were improved to prevent similar misconfigurations in the future.

Corrective and Preventative Measures: To address the issue and improve overall system reliability, the following measures will be taken:

1. Conduct a thorough review of load balancer configurations to identify and correct any potential misconfigurations.

2. Enhance monitoring and alerting systems to provide early detection of load balancer issues.

3. Implement automated testing and deployment processes to validate load balancer configurations before production deployments.

4. Conduct regular load testing to ensure the scalability and performance of the authentication service under different traffic conditions.

5. Establish incident response protocols to streamline communication and escalation procedures during outages.

In conclusion, the web stack outage incident was caused by a misconfiguration in the load balancer, resulting in the unavailability of the authentication service. The issue was promptly identified and resolved by correcting the load balancer configuration. Steps will be taken to prevent similar incidents in the future by implementing corrective and preventative measures outlined above.