Sergio Fernández

Now

Through Xebia I work with The Walt Disney Company on platform engineering: GitHub Enterprise and GitOps migrations, Terraform enablement, identity and access, AWS and GCP. I also run the technical interviews for Xebia's contractor hires. I also collaborate with San Francisco-based projects on AI agent infrastructure.

For fun, open source and a homelab: about 200 public repositories on GitHub and a blog where I write up what breaks and what I learn.

Latest on the blog

1. Why I built akou, one app for my calls and my dictation
2. Overengineering in DevOps, and the network project that could have been an email
3. What disaster recovery needs when the region dies
4. Deploying a three-node Garage S3 cluster and hooking it up to Duplicacy
5. Building a GenieACS MCP server in Go so an LLM can manage routers

Experience

• Jul 2025 to now
  Senior DevOps Engineer II, Xebia, Spain

  Cloud platform for the identity area of The Walt Disney Company, serving millions of concurrent users: reusable Terraform modules for AWS through Atlantis and Terraform Enterprise, GitHub Enterprise and GitOps migrations, SRE and observability, and leading AI adoption for hundreds of developers. Technical interviews for Xebia's contractor hires.

• Jul 2023 to Jun 2025
  AI and DevOps Consultant, ACSdesk, freelance

  Built the compatibility layer that let Kubeshark run on OpenShift. For TrustYou, moved Sentry to GlitchTip, ran Hetzner infrastructure, traced a Loki disk-space leak and rightsized clusters with KRR and GitOps. Founded LynxPrompt. AI adoption consulting and workshops for Spanish companies.

• Jan 2021 to Jun 2025
  Senior DevSecOps Engineer, Claranet Deutschland GmbH, Germany

  Kubernetes managed services for enterprise clients in Germany. I led the Kubernetes production readiness assessment product, now in the company's portfolio, patch and upgrade management across dozens of clusters, disaster recovery planning as the internal specialist, and the move off Docker Hub. Started the company's Amazon EKS offering. GCP and AWS expert consultant.

• Jan 2020 to Dec 2020
  MLOps Engineer, Telcaria Ideas SL, Spain

  5G-DIVE, an EU and Taiwan research project: a PaaS and MLaaS on fog and edge resources with K3s, Helm, H2O.ai, GitLab CI and ArgoCD.

• Feb 2019 to Jan 2020
  DevOps Consultant, Culture of Insight, UK, freelance

  Took an R analytics app for Twitch to production with Docker on DigitalOcean and App Engine.

• May 2016 to Dec 2019
  Founder, GenieACS Engineer, ACSdesk, Spain

  My own company. Deployed and operated GenieACS zero-touch CPE provisioning for ISPs in Spain, Switzerland, Chile and India. The container and Helm chart and the systemd services from that work are still the most used ones; how I deploy it and the API recipes are on the blog.

• Feb 2019 to Dec 2019
  Software and Cloud DevOps Engineer, AP Data Services Ltd, UK

  R Shiny products for UK financial services and car-part resellers, on ShinyProxy and AWS. AdamPartsFinder is the price-comparison proof of concept from that time.

• May 2018 to Jul 2019
  Technical Partner, Good Peoples Connected, France

  Designed an IoT Wi-Fi voucher device on Raspberry Pi for hotels in Guadeloupe: Python, Ansible and AWX, Vault, FreeCAD enclosures. Code: PiSpot-Watch, PiSpot-Show.

• Sep 2017 to Sep 2018
  NetDevOps and Software Engineer, Anvimur Telecomunicaciones, Spain

  Automated router deployment for an ISP: ONT integration, Huawei OLT, TR-069, and a LibreACS to GenieACS migration.

• Mar 2016 to Aug 2017
  Software, Network and Systems Engineer, InnoXess, Switzerland

  GenieACS deployment and maintenance for a Swiss project: Ruby on Rails, MongoDB, Redis, Docker.

• Jul 2015 to May 2016
  Software, Network and Systems Engineer, Electrónica Martínez, Spain

  Internship, then hired. Cut new-customer router setup from 30 minutes to 3 with zero-touch provisioning (router-express), built the "impossible" hotspot map of 200+ APs (statix, services-isp), and moved the company to Odoo (import-xgest-odoo).

• Jul 2014 to Sep 2014
  Control and Optimization Engineer, Repsol, Spain

  Internship. Honeywell process control systems, PID and multivariable control.

Projects

Open source, on GitHub, by stars. Stars as of 2026-09-29.

• Telegram-Archive Own your Telegram history: incremental backups with a local viewer that feels like the real app. Site
  215 stars
• genieacs-container The original and most used container and Helm chart for GenieACS. Guide
  135 stars
• VPN-Bypass macOS menu-bar app for per-domain VPN routing, with a CLI.
  122 stars
• whisper-subs Jellyfin plugin that generates subtitles locally with Whisper. Site
  103 stars
• CashPilot Self-hosted passive income platform: deploy once, track earnings. Site
  53 stars
• LynxPrompt Self-hosted, federated platform for AI IDE rules and commands (AGENTS.md, CLAUDE.md). Site
  49 stars
• DeclaRenta Turns foreign broker reports into Spanish tax filings (Modelo 100, 720, 721, D-6). Free, private, self-hosted. Site
  48 stars
• Pumperly Open-source fuel and EV route planner with real-time prices. Site
  38 stars
• Wayback-Archive Download complete websites from the Wayback Machine for offline viewing.
  38 stars
• smart-covers Jellyfin plugin: cover extraction from PDF, EPUB and audiobooks.
  18 stars

Education

• 2020 to 2022
  MSc Data Engineering, Edinburgh Napier University

  Dissertation on disaster recovery of managed Kubernetes (EKS, GKE).

• 2011 to 2015
  BEng Telecommunication Systems Engineering, Universidad Politécnica de Cartagena

  Graduated second in class. My final project, zero-touch CPE provisioning with DHCP option 66 and TR-069, received an honourable mention.

Certifications

• AWS Certified Solutions Architect, Professional, 2026
• GitHub Actions (Microsoft), 2025
• Certificate in Advanced English, C1 (Cambridge), 2020
• CKA, Certified Kubernetes Administrator, 2021 to 2024, expired
• AWS Certified Solutions Architect, Associate, 2020 to 2023, expired
• HashiCorp Certified Terraform Associate, 2020 to 2022, expired
• Huawei Certified Network Associate, Routing and Switching, 2018 to 2021, expired

Skills

AI

Agent tooling and MCP servers in Go and TypeScript; Claude Code and Codex workflows and automation; local speech recognition and LLM inference; rules and prompt management for AI IDEs; and a million other innovations I can't talk about yet.

DevOps and platform

Kubernetes (GKE, EKS, AKS, OpenShift, Rancher, K3s), Helmfile, Kustomize, Docker. AWS, GCP, DigitalOcean, on-prem and hybrid networking. Terraform, Terragrunt, Terraform Enterprise, Atlantis. GitHub Enterprise, GitHub Actions, ArgoCD, GitLab CI, Jenkins, Tekton. Prometheus, Grafana, Loki, Tempo, Datadog. Nginx, Caddy, Istio, Keycloak. Routing, switching, VPNs, TR-069.

Software

Go, Python, TypeScript, Bash, R, Swift, C#. REST API design, distributed systems. PostgreSQL, MySQL, SQLite, MongoDB, Cassandra, Redis.