🔹 Resilience Lifecycle

A repeatable process to embed resilience in every workload:

1. Set Objectives → Define critical apps, user stories, and resilience metrics.
2. Design & Implement → Understand dependencies, build DR strategies, CI/CD, safe failure.
3. Evaluate & Test → Load testing, DR drills, chaos engineering, synthetic testing.
4. Operate → Continuous monitoring, observability, event management.
5. Respond & Learn → Incident reviews, training, metrics reviews, and knowledge base building.

Action:
Turn this into a cycle — after each release or incident, revisit objectives, test, and improve.

🔹 Resilience Tiers

Resilience is not one-size-fits-all. Workloads should be mapped to clear targets:

• Silver (99.95%) → Standard business systems.

  • RTO: 24 hrs

    RPO: 12 hrs

• Gold (99.99%) → Business-critical or security systems.

  • RTO: 1 hr

    RPO: 30 min

• Platinum (99.995%) → Critical infrastructure / national-scale systems.

  • RTO: 15 min

    RPO: 1 min

Action:
Map each workload to a tier. Don’t overspend on Platinum for apps that only need Silver.

🔹 Architectural Patterns

Proven approaches to withstand failure:

flowchart TB
  Platinum[Platinum<br/>Multi-region DBs<br/>e.g. DynamoDB Global Tables<br/>Cloud Spanner]
  Gold[Gold<br/>Multi-region replication<br/>e.g. Aurora Global DB<br/>CosmosDB]
  Silver[Silver<br/>Regional instances<br/>Basic recovery]

  Platinum --> Gold --> Silver

Key Questions:

• How will the system handle load spikes?
• How do we detect and recover from data corruption?
• How do we prepare for gray failures (partial degradation)?

Action:
Choose patterns that match the assigned tier. Build runbooks for load, database, and service failure scenarios.

🔹 Building a Resilience Strategy

A complete strategy includes:

flowchart TD
  Req[Requirements & Scope] --> Fail[Failure Modes]
  Fail --> Obs[Observability<br/>Metrics/Logs/Tracing]
  Obs --> Ops[Operations & Tools<br/>Runbooks, CI/CD, Chaos]
  Ops --> Req

Action:
Document a resilience playbook for each workload with failure modes, observability dashboards, and operational runbooks.

🔹 Operational Practices

Resilience is a culture as much as a design:

flowchart TD
  SO[Service Ownership] --> ORR[Operational Readiness Reviews]
  ORR --> CD[Safe Continuous Deployment]
  CD --> CoE[Correction of Errors]
  CoE --> SO

• Service Ownership → Teams own reliability end-to-end.
• Safe Continuous Deployment → Automate to reduce risk.
• Correction of Errors (CoE) → Root cause analysis and prevention.
• Operational Readiness Reviews (ORR) → Validate resilience before launch.

Action:
Make ORRs, CoEs, and service ownership standard rituals across teams.