The part of the network
nobody sees, written down.

Notes from the day job, the homelab, and whatever I’m taking apart this month.

01 Field Notes. Written by me.

Sealed Secrets on K3s: Versioning Secrets in Git Without Fear

In the previous post I showed how to turn on GitOps on a K3s cluster with ArgoCD: git became the source of truth and 32 applications started syncing on their own. One essential piece was missing: secrets. Database passwords, API tokens, keys — things that can’t go…

Homelab GitOps: ArgoCD on K3s, from Zero to App-of-Apps

This tutorial walks you from manual kubectl apply to a Kubernetes cluster fully managed by git — the GitOps model — using ArgoCD on a single-node K3s. Every step explains the concept before the command. At the end you’ll have the complete workflow: edit, commit, push,…

IoT + Cloud: A Three-Layer Architecture

A practical approach to architecting scalable IoT systems using three well-defined layers: devices, edge, and cloud. Ideal for anyone who needs to decide where to process data without reinventing the wheel.

IoT MQTT mTLS Stack → Kafka → ksqlDB

A complete IoT data pipeline: devices publish via MQTT with mTLS, EMQX routes to Kafka, and ksqlDB turns everything into real-time SQL. On-premise, secure, and scalable.

Visualizing IBGE Maps with Python and Jupyter

A step-by-step tutorial for visualizing geographic maps of Brazil using Python, Jupyter Notebooks, and IBGE territorial data. Useful for projects that require spatial analysis.

Traefik: Managing Self-Hosted Applications

How to use Traefik to manage self-hosted applications elegantly: automatic service discovery, Let’s Encrypt, and load balancing with zero manual configuration.

02 Field notes. Written by an LLM that did the work.

Sealed Secrets on K3s: Versioning Secrets in Git Without Fear

In the previous post I showed how to turn on GitOps on a K3s cluster with ArgoCD: git became the source of truth and 32 applications started syncing on their own. One essential piece was missing: secrets. Database passwords, API tokens, keys — things that can't go into git in…

Homelab GitOps: ArgoCD on K3s, from Zero to App-of-Apps

This tutorial walks you from manual kubectl apply to a Kubernetes cluster fully managed by git — the GitOps model — using ArgoCD on a single-node K3s. Every step explains the concept before the command. At the end you'll have the complete workflow: edit, commit, push, and watch the cluster…

03 Reference

Diagrams, cheat sheets and templates I built for myself and had no reason to keep private.

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04 Contact

Ask me something.

If you’re stuck on Telco, Cloud, or an IoT platform that stopped behaving, write to me. I answer questions from strangers. it’s usually how the next post starts.

If you need a deep dive, an architecture review, or dedicated consulting, let’s talk business.

muller@mfs.eng.br