Security Guides for Linux, Docker and CI/CD

The Security section explains how to protect the systems you run, without fear-driven advice or vague checklists. We cover the practical side of security for servers, containers and delivery pipelines: hardening SSH, handling secrets, keeping software patched, reducing what an attacker can reach, and understanding the warnings that tools print after an update.

Each guide explains why a change matters before showing how to make it, and it tells you how to check that the change worked without locking yourself out. Configuration changes are tested in throwaway containers or virtual machines where that is possible, and the guide says clearly when a step relies only on the vendor's documentation or on a security advisory.

Security topics often start in another section. A Linux upgrade, a new Docker image or a retired Kubernetes component can all create risk, so the guides here link back to the Linux, Docker and DevOps sections where the original task is explained. Use the latest posts below to keep up with new warnings and fixes.

What this section covers

  • SSH hardening, key types and post-quantum key exchange
  • Secrets in CI/CD: tokens, OIDC and pinning actions to a commit
  • Patching, end-of-life software and safe upgrade paths
  • Container and image security basics
  • Explaining new security warnings and advisories in plain language

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