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Welcome to this lesson on TLS certificates in Kubernetes. TLS (Transport Layer Security) is the foundation of secure communication in modern distributed systems. In Kubernetes, TLS protects API traffic, secures service endpoints, and validates identities between components. This lesson builds practical, hands-on knowledge so you can generate, inspect, configure, and troubleshoot certificates used by Kubernetes.
A pie chart titled "Poll on TLS Certificates" showing responses by colored slices, with the largest blue slice labeled 36.1% and an orange slice labeled 26.0%. A legend on the right lists response options including "No Clue" and "Not very Comfortable."
What you’ll gain from this section:
  • A clear explanation of TLS certificates, private keys, and certificate authorities (CAs).
  • Hands-on steps to generate and inspect X.509 certificates using common tools (e.g., openssl).
  • How to configure TLS for Kubernetes services and API endpoints.
  • Understanding of how Kubernetes issues, consumes, and validates certificates internally.
  • Practical troubleshooting techniques for common certificate failures (hostname mismatches, expired certs, incorrect CA chains, key/cert format issues).
If you already know TLS basics (certificates, private keys, and CAs), feel free to focus on the Kubernetes-specific material in this section.
A dark-blue presentation slide titled "Goals" showing six rounded bullet points about TLS certificates and Kubernetes. The points ask what TLS certificates are, how to generate/view/configure them, how Kubernetes uses them, and how to troubleshoot related issues.
How this lesson is organized
  • Concepts first: brief, practical definitions (certificate, CA, key, CSR, SAN, chain).
  • Hands-on examples: commands to create keys/CSRs and issue certificates with a CA (openssl examples).
  • Kubernetes integration: how kube-apiserver, kubelet, and ingresses use certificates; where certs live (/etc/kubernetes/pki, Secrets, etc.).
  • Troubleshooting checklist: verifying chains, comparing Subject Alternative Names (SANs), checking expiration, and decoding certs for human-readable diagnostics.
Quick reference links Topics covered (high level) This lesson uses a practical approach: concise conceptual explanations, reproducible commands, and Kubernetes-focused examples so you can confidently configure TLS and resolve certificate problems in real clusters.

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