What's causing the sudden increase in DNS query latency for Cloudflare customers in Southeast Asia?

Introduction

The sudden increase in DNS query latency for Cloudflare customers in Southeast Asia is a critical issue that demands immediate attention. As we delve into this problem, we'll employ a systematic approach to identify, validate, and address the root cause while considering both short-term fixes and long-term strategic implications.

Our analysis will follow a structured framework, beginning with clarifying questions to establish context, followed by a thorough examination of potential causes, data analysis, and hypothesis formation. We'll then move on to root cause analysis, validation steps, and finally, a comprehensive resolution plan.

Step 1

Clarifying Questions (3 minutes)

• I'm noticing the focus on Southeast Asia. Would you say this issue is isolated to this region, or are we seeing similar patterns elsewhere?

Why it matters: This helps determine if it's a localized problem or a broader systemic issue. Expected answer: The issue is primarily affecting Southeast Asia. Impact on approach: If isolated, we'll focus on regional infrastructure; if widespread, we'll investigate global systems.

• Considering the suddenness of the increase, have there been any recent deployments or configuration changes in our Southeast Asian infrastructure?

Why it matters: Recent changes often correlate with performance issues. Expected answer: A minor configuration update was pushed last week. Impact on approach: If confirmed, we'll prioritize reviewing and potentially rolling back recent changes.

• Are we seeing any patterns in the types of DNS queries experiencing increased latency?

Why it matters: This could point to specific services or record types being affected. Expected answer: The latency increase is uniform across query types. Impact on approach: If uniform, we'll look at broader infrastructure issues; if specific, we'll focus on those query types.

• Has there been any change in traffic patterns or volume from Southeast Asian customers recently?

Why it matters: Unusual traffic patterns could indicate external factors or potential DDoS attacks. Expected answer: Traffic volume has remained relatively stable. Impact on approach: If stable, we'll focus on internal factors; if changed, we'll investigate potential external causes.

• Are we certain that our monitoring systems are accurately reporting this latency increase?

Why it matters: Ensures we're not chasing a non-existent problem due to faulty monitoring. Expected answer: The monitoring systems have been cross-verified and are accurate. Impact on approach: If confirmed accurate, we proceed with analysis; if uncertain, we first validate our monitoring systems.