Why this matters
- Rolling updates and blue/green deploys keep BookStore selling during releases.
- Database migrations must be backward compatible across old and new pods.
- SRE interviews tie deploy strategy to error budgets and health probes.
Rolling updates
L1 · FresherKubernetes replaces pods gradually while readiness probes gate traffic to healthy instances.
Blue-green
L2 · IntermediateSwitch traffic between two environments after smoke tests — fast rollback by flipping routes.
Feature flags
L3 · AdvancedDecouple deploy from release — dark launch new checkout flow to internal users first.
Database compatibility
L4 · ExpertShip schema changes compatible with both old and new app versions during rolling deploys.
StreamHub production architecture (AWS)
Hook
BookStore deploys ten times a day. Rolling updates must not drop connections or serve incompatible API contracts to mixed client versions during the cutover.
Backward-compatible schema
Expand-contract migrations: add nullable columns first, deploy code that writes both fields, backfill, then remove old columns in a later release. Flyway scripts align with this sequence.
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Still to come · 6 sections
- Blue-green or rolling with health
- API compatibility
- BookStore in action
- Runnable BookStore lab
- Failure modes in production
- Session and sticky traffic
Test yourself
Answer these before moving on — recall is what makes it stick.