Deployment, Migration & Rollback

Failure modes and blast radius, SLOs and error budgets, the three signals of observability, the retry patterns that cause outages rather than preventing them, and shipping a schema change without downtime.

This module is 06.5 of the 5 in Reliability & Operations. It runs about 4 hours across 5 lessons, and closes with Expand/Contract — Rename a column on a 900 million row table with zero downtime and a working rollback at every step.