On-callMediumoc-g020

Subject Disk fullLevel Mid–Senior~30 minCommon in Storage & CDN · Reliability & on-call interviewsIndustries Technology, Software development

Question

At 20:30, multiple unrelated services on the same Kubernetes node start failing health checks and pods are getting evicted with 'DiskPressure'. The node's root/ephemeral disk is at 100%. A change this afternoon bumped one service's log level to DEBUG, and it's been emitting verbose JSON logs at high volume; container logs aren't being rotated/shipped fast enough. How do you triage, restore the node, and prevent recurrence?

What a strong answer looks like

Stop the bleeding first (mitigate), then form hypotheses from real signals. Separate root cause from symptom, communicate status as you go, and close with what prevents a repeat.

Learn the concepts

Diagram & narrate the incident

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Run or narrate your approach, then ask the coach.