Kubernetes in practice, starting with Secrets: creating, mounting, projecting and rotating them.
What a Secret actually is, how kubectl builds one from an env file (and what it rejects), why base64 is not encryption, and who can really read it.
Why a rotated Secret reaches mounted files after about a minute but never reaches environment variables or subPath mounts, and why files leak less than env vars.
Mounting several Secrets into one directory with a projected volume, the silent last-source-wins key collision that comes with it, and how items/path keeps tenants apart.