The Time it Wasn't DNS

In this presentation, Sean Klein, a principal technical program manager for Modern Incident Analysis at Microsoft Azure, discusses a global outage experienced by the Microsoft Azure Wide Area Network in January 2023. Despite assumptions, the root cause was not DNS but rather involved BGP among other contributing factors.

Key Points:

• Role of Incident Analysis: Sean has a unique role in deep incident analysis, converting outages into detailed reports using modern methodologies, distinct from traditional problem management approaches.
• Simplicity vs Complexity: There is a human tendency to simplify complex problems into easily understandable narratives. However, simplification can hide the true nature of outages, which are often multifaceted, involving more than just a single factor like DNS or human error.
• Impact of Narratives: Simplified outage stories can mislead and result in inappropriate solutions, such as penalizing individuals unnecessarily or enforcing unnecessary policy changes, which might not address the actual problems.
• Communication during Incidents: The need for clear and accurate communication is emphasized, especially when relaying information to leaders and customers, to avoid oversimplification and blame-oriented narratives.

Conclusion: It's critical to resist the urge to oversimplify incidents. Comprehensive analysis is necessary to understand and learn from outages fully, as explanations are rarely straightforward and involve a combination of systems and human factors.

This is the end of the AI-generated content.

In January of 2023, the Microsoft Azure Wide Area Network experienced a global outage. If you were a Microsoft customer at the time, you were impacted by this outage. Sean walks us through the numerous factors - events and conditions - that contributed to the outage and explains why it's not always DNS. (Spoiler: sometimes it's BGP)