Why did Google Cloud VM launch time increase to 5 minutes?

Introduction

The sudden increase in Google Cloud VM launch time to 5 minutes is a critical issue that demands immediate attention. This performance degradation could significantly impact user experience, operational efficiency, and potentially lead to customer churn. I'll approach this problem systematically, focusing on identifying the root cause, validating hypotheses, and developing both short-term fixes and long-term solutions.

Step 1

Clarifying Questions (3 minutes)

• Looking at the timing, I'm thinking this might be a recent change. When exactly did you first notice this increase in launch time?

Why it matters: Helps pinpoint potential triggers and narrows down the investigation timeframe. Expected answer: Within the last week or two. Impact on approach: Recent changes would be prioritized in the investigation.

• Considering the complexity of VM launches, I'm wondering if this affects all VM types and sizes. Is the 5-minute launch time consistent across all VM configurations?

Why it matters: Identifies whether the issue is systemic or specific to certain VM types. Expected answer: It affects most VM types, but with some variations. Impact on approach: If consistent, focus on shared infrastructure; if varied, investigate specific VM configurations.

• Given the potential impact on users, I'm curious about the scale. What percentage of VM launches are experiencing this delay?

Why it matters: Determines the severity and scope of the problem. Expected answer: A significant portion, over 50%. Impact on approach: High percentage would indicate a systemic issue rather than an isolated incident.

• Thinking about recent changes, have there been any significant updates to the VM launch process or underlying infrastructure in the past month?

Why it matters: Identifies potential triggers for the performance degradation. Expected answer: Yes, there was a recent update to the resource allocation system. Impact on approach: Would focus investigation on recent changes and their impact.

• Considering the importance of monitoring, I'm wondering about our alerting systems. Were there any warning signs or gradual increases in launch times before reaching the 5-minute mark?

Why it matters: Assesses the effectiveness of current monitoring and identifies potential early indicators. Expected answer: Some minor fluctuations were observed but not flagged as critical. Impact on approach: Would include a review and potential enhancement of monitoring systems in the solution.