47. Further reading: the real-life references

Official documentation (the primary sources)

Kubernetes docs: kubernetes.io/docs. Especially Concepts → Workloads, Configure Liveness, Readiness and Startup Probes, Pod Lifecycle, Production environment, and Security checklist.
Docker docs: docs.docker.com. Building best practices, Multi-stage builds, Build secrets, Compose file reference.
OpenTelemetry docs: opentelemetry.io/docs. Go getting started, the Collector configuration, and Semantic Conventions for HTTP and messaging.
Prometheus (prometheus.io/docs) and Prometheus Operator docs; the Grafana Loki and Tempo docs.
Gateway API (gateway-api.sigs.k8s.io), Argo CD and Argo Rollouts (argo-cd.readthedocs.io, argoproj.github.io/rollouts), KEDA (keda.sh), CloudNativePG (cloudnative-pg.io), Karpenter (karpenter.sh), Kyverno (kyverno.io).

Books

Kubernetes in Action, 2nd ed. (Marko Lukša): the deepest practitioner's explanation of how Kubernetes works.
Production Kubernetes (Rosso, Lander, Brand, Harris): building platforms on Kubernetes; real trade-offs from VMware field engineers.
Kubernetes Patterns, 2nd ed. (Ibryam & Huß): sidecar, ambassador, init container, operator and more, as reusable patterns.
Docker Deep Dive (Nigel Poulton): short, current, practical.
Site Reliability Engineering and The Site Reliability Workbook (Google, free at sre.google/books): SLOs, burn-rate alerting (Workbook ch. 5), postmortems.
Observability Engineering (Majors, Fong-Jones, Miranda).
Learning OpenTelemetry (Young & Parker).
Designing Distributed Systems, 2nd ed. (Brendan Burns).
Container Security (Liz Rice), and Hacking Kubernetes (Martin & Hausenblas) for the attacker's view.

Field guides and real-world material

Kubernetes Failure Stories, k8s.af: public postmortems; read them.
learnk8s.io: excellent deep dives (graceful shutdown, CPU limits, architecture, the "troubleshooting deployments" flowchart).
Google Cloud Kubernetes best practices, AWS EKS Best Practices Guide (aws.github.io/aws-eks-best-practices), Azure AKS baseline architecture. These are opinionated, battle-tested checklists.
CNCF Cloud Native Security Whitepaper and the NSA/CISA Kubernetes Hardening Guide.
OpenGitOps principles (opengitops.dev), SLSA (slsa.dev), Sigstore (sigstore.dev).
Brendan Gregg's USE Method and Tom Wilkie's RED Method write-ups.
Henning Jacobs' Kubernetes on AWS: CPU limits talks and the "Stop using CPU limits" discussion; read both sides before deciding (§23.3).

Practice

killercoda.com and killer.sh: browser-based Kubernetes labs (and CKA, CKAD and CKS exam simulators). CKA → CKAD → CKS is a sensible certification order once you've finished this guide.
Re-run §43's acceptance tests after every significant change to the platform. That's what keeps this system production-grade.