# Joe's Personal Blog

> Technical articles about Kubernetes, cloud-native infrastructure, observability, platform engineering, containers, security, and open source.

This file provides a concise, LLM-friendly index of the published content on https://jkroepke.de/. Prefer the linked Markdown versions for article content and the canonical HTML pages for normal browsing.

## About
- [Jan-Otto Kröpke](https://jkroepke.de/about/index.md): Principal Cloud Architect and author of this blog.

## Articles
- [Preparing for CKNE: What I Learned From the Beta Exam](https://jkroepke.de/2026/09/preparing-for-ckne-what-i-learned-from-the-beta-exam/index.md): Published 2026-09-17 — My experience with the new Certified Kubernetes Network Engineer beta exam, what I would prepare around Cilium, Istio, Gateway API, Kubernetes networking, and why time management matters.
- [Kubernetes Image Volumes for Platform-Managed Runtimes - Part 1](https://jkroepke.de/2026/07/kubernetes-image-volumes-for-platform-managed-runtimes-part-1/index.md): Published 2026-07-23 — Kubernetes image volumes make it possible to separate application artifacts from their language runtimes. This brings back a responsibility model that was common before containers: application teams deliver applications, while platform teams maintain and patch the runtime.
- [Handling Large Files and CRDs in Helm and the 1MB Release Limit](https://jkroepke.de/2026/02/handling-large-files-and-crds-in-helm-and-the-1mb-release-limit/index.md): Published 2026-02-18 — Helm releases are stored as Kubernetes Secrets, which have a hard 1 MiB size limit. This post explores why this limit exists, how large CRDs exacerbate the problem, and practical techniques for chart maintainers to reduce release size using subcharts, minification, and compression.
- [The False Security of Pinned GitHub Actions Commit Hashes](https://jkroepke.de/2025/08/the-false-security-of-pinned-github-actions-commit-hashes/index.md): Published 2025-08-07 — An exploit reveals a hidden security flaw in GitHub Actions. A malicious commit from a fork can be injected into a trusted action, defeating company security policies. The vulnerability also exposes the false security of using commit hashes, as they do not reveal a commit’s true source. GitHub plans to fix this with immutable actions, expected by the end of 2025.
- [DNS Hijacking in Kubernetes](https://jkroepke.de/2025/07/hijack-dns-domains-inside-kubernetes/index.md): Published 2025-07-09 — Kubernetes DNS, while convenient, harbors a security risk: a lack of understanding regarding its resolution mechanisms permits attackers to redirect cluster traffic without exploits, simply by creating specific namespaces and services. Effective protection hinges on policy, strict naming conventions, controlled permissions, and egress restrictions.

## Optional

- [Posts archive](https://jkroepke.de/posts/): Human-readable archive of all posts.
- [Sitemap](https://jkroepke.de/sitemap.xml): Complete XML sitemap.
- [Source repository](https://github.com/jkroepke/blog): Hugo source for this site.