Debug and mitigate a CPU spike incident

Production Debugging: CPU Spike Incident (Open-Ended)

You are on-call for a backend service. An alert fires: CPU usage suddenly spikes on the service’s hosts/pods and stays high.

You can ask for any information you want (dashboards, time series metrics, logs, traces, recent deploys, config changes). The interviewer will provide whatever graphs/logs you request.

Tasks

1. Immediate mitigation: What do you do first to reduce user impact?
2. Triage plan: What key questions do you ask and what metrics/logs do you inspect?
3. Root cause analysis: Walk through how you narrow down hypotheses to a likely root cause.
4. Fix + verification: How do you validate the fix and prevent regression?

Assume this is a typical microservice environment (Kubernetes or VM autoscaling, load balancer, centralized logging/metrics).