Incident response
Establish the situation
- Record the current time, impact, affected scope, and incident start time.
- Identify what is confirmed, what is inferred, and what remains unknown.
- Define the expected behavior and the observed deviation.
- Determine whether impact is growing, stable, or recovering.
Build the timeline
Collect timestamps for:
- First customer or monitoring signal.
- Deployments and configuration changes.
- Dependency failures and recovery events.
- Operator actions and automated mitigations.
- Changes in traffic, capacity, latency, errors, and resource pressure.
Normalize timestamps before drawing conclusions.
Manage hypotheses
For every hypothesis record:
- Evidence that supports it.
- Evidence that contradicts it.
- The smallest safe test that could disprove it.
- Confidence and remaining unknowns.
Prefer discriminating tests over collecting more undirected data.
Mitigate safely
- Prefer reversible, well-understood actions.
- State blast radius and rollback before acting.
- Do not combine several mitigations when one can be evaluated independently.
- Preserve diagnostic evidence when possible.
- Separate immediate impact reduction from permanent remediation.
Close the investigation
Produce:
- Impact summary.
- Confirmed timeline.
- Root cause with supporting evidence.
- Trigger and contributing factors.
- Mitigation and recovery.
- Detection and response gaps.
- Prioritized follow-up work with owners when known.