Postmortem: Web Stack Downtime November 10, 2023
Published: 2023-11-12 19:53:13

Issue Summary:
 Duration: November 10, 2023, 2: 30 - 6:444 45 (UTC)
 Impact :  Add user authentication service drawback: 
 Impact: Add user authentication service Disadvantage: , affecting 30% of active users.
 Root Cause: Misconfiguration in  load balancing settings leads to increased traffic on the authentication server.
 Timeline: 
14: 30: The issue was discovered through an increased error rate on the authentication service.
 14: 35: Monitoring alerts are triggered when the error rate is high.
 14: 40: An initial investigation has begun, assuming a potential database connectivity issue.
 15: 00: Database connection checked; The focus has shifted to application servers.
 15: 30: Wrong assumption that recent code deployment may cause problems; start recovery.
 16: 00: Recovery completed; No improvement was observed.
 Reported to  infrastructure team.
 16: 30: Further investigation revealed that load balancing settings were misconfigured, resulting in uneven traffic distribution.
 17: 00: Load balancing settings have been fixed and traffic has begun to normalize.
 18: 45: Full service recovery confirmed.
 Root cause and resolution: Root cause: Misconfiguration in  load balancing settings causes traffic to be distributed unevenly, overloading the authentication server.
 Resolution : Fixed load balancing settings  to evenly distribute traffic between application servers, resolving bottlenecks.
 Corrective and preventive actions: Improvements/fixes: Check automatic load balancing configuration: Perform automated testing to verify load balancing configuration, preventing errors configuration.
 Enhanced Monitoring: Improve monitoring systems to detect and alert on load balancer anomalies in real-time.
 Incident Response Training: Provide additional training for the team on efficient incident response and debugging strategies.
 Tasks to Address the Issue: Automated Load Balancer Checks: Implement a script to regularly check load balancer configurations, alerting on any deviations from best practices.
 Monitoring Enhancements: Add custom monitoring metrics specifically for load balancer health and distribution.
 Documentation Update: Update the incident response playbook with steps to investigate and correct load balancer-related issues.
 Team training: Conduct workshops on load balancing management and troubleshooting for  infrastructure teams.
 Conclusion:
 The outage on November 10, 2023 was due to misconfiguration in  load balancing settings, which increased traffic to the authentication server and made it unavailable.
 The initial assumption of a database problem led to  efforts being temporarily derailed during the investigation.
 Once identified,  corrective action includes adjusting  load balancing settings to evenly distribute traffic, thereby restoring service.
 To prevent future incidents, automated load balancing configuration testing, enhanced monitoring, and additional incident response training have been identified as important improvements.
 A series of specific tasks, including creating scripts for automated control and conducting workshops, were outlined to address these issues and strengthen the system against similar problems in the future.