# Sre
All Sre notes →1 — Incident Response Lifecycle
Detect, triage, mitigate, resolve, review — the phases every incident moves through, and why skipping the review phase is how the same incident happens twice.
10 — Blameless Postmortems
Why a blameless structure is what makes Five Whys produce an honest systemic answer instead of a defensive, cover-yourself one.
11 — Communication During Incidents
Status page updates, stakeholder comms, and internal channel discipline — the incident-adjacent work that determines how the outage is remembered as much as the fix does.
12 — Chaos Engineering
Deliberately injecting failure in a controlled experiment to validate the failure modes a design only claims to handle, before production finds them for you.
13 — Game Days
Scheduled, team-wide incident simulations that build on-call muscle memory and test the runbooks nobody's had to actually use yet.
2 — Severity Classification
The objective criteria that decide how big a response an incident gets, so severity is a judgment call made once, consistently, not renegotiated mid-incident.
3 — Incident Command System
The role structure — commander, comms lead, ops lead — that keeps a live incident from collapsing onto one overloaded engineer trying to do everything at once.
4 — On-call Engineering
Designing the rotation and escalation policy itself as an engineering problem, not just a schedule — the discipline distinct from the day-to-day on-call handbook.
5 — Escalation Policies
What happens when the first responder doesn't acknowledge in time, and the escalation chain that has to be correct precisely when everyone is least likely to check it.
6 — Runbooks
Step-by-step operational procedures written before the incident, so 3am execution doesn't depend on anyone's memory of how a system behaves under stress.
7 — Playbooks
Decision trees for ambiguous or novel incidents, one level up from a runbook's fixed steps — how to reason through a failure mode nobody's documented yet.
8 — Root Cause Analysis
Moving past 'a bad deploy caused it' to the systemic condition that let a bad deploy reach production undetected in the first place.
9 — Five Whys
The simplest RCA technique that works — repeatedly asking why until you hit a structural cause — and where it breaks down on genuinely multi-causal incidents.