One apartment. Datacenter rules.
AI agents propose. Humans gate. Observation decides truth.
An apartment datacenter run the way a platform team runs a cloud: git records intent, CI gates every infrastructure change, AI agents do the typing — and a human keeps merge and apply authority. The hardware is ordinary. The operating model is the point.
Pick your depth
- the tour The tour Photos, what runs, why each thing is there — and what was deliberately left out.
- the architecture The architecture Zones, states, the change pipeline, the migration, the decisions and the accepted weak spots.
- deep dive Field notes Dated deep dives — backups, incidents, drills — each checked against the running system.
In plain terms
What it is. A normal apartment has one box from the internet provider and a handful of subscriptions. This one runs its own small cloud: the things most households rent from Google, Apple or Amazon — photos and music, the smart home, the websites, even the password vault — run on two shoebox-sized computers and a storage box under a desk in Cologne. Nothing on these machines has to phone home to work: when the internet is down, the lights and the music keep working.
How far it goes. The network closet of a mid-sized office, run with the working rules of a cloud provider. Three professional switches, two firewalls that stand in for each other, two servers that vote with a third party as tie-breaker, a secrets vault, monitoring, and a pipeline that checks every change before it happens. All of it has to stay quieter than the hi-fi next to it — which is why it is small, and why nothing in it is allowed to whine.
How a change happens. Nobody, human or AI, walks in with a screwdriver. Every change is a building-permit application: it is written down, an automatic check confirms it is plausible, and only then does a human read it and press the button that makes it real. Afterwards the system is inspected to confirm the change did what the paperwork said. The AI is the draughtsman who writes the applications; the human is the building inspector, and the stamp stays with the human. There is one human here, though, so the inspector is also the person who ordered the drawing — the second pair of eyes the rule implies does not exist. That is the thinnest part of the whole arrangement, and there is no point pretending otherwise.
Why the doors are locked. The apartment’s devices live in eight separate rooms — guest Wi-Fi in one, the websites the apartment publishes in another, the smart plugs, the password vault and the management tools each in their own — and the doors between them open only where a written rule says so. A hotel works the same way: your key card opens your room and the lift, not the safe behind reception. Keys expire, too: a job that needs a password gets one that dies minutes later, so there is no master key on a hook by the door.
What is proven, and what is not. Two firewalls share one front desk and one notepad; if one collapses, the other continues the conversation without the caller noticing — that hand-over has been rehearsed once, gently, not yet with the plug pulled. The two servers do the same for each other, and that has been rehearsed twice. Once as a planned shutdown: the services were moved across to the other machine on purpose beforehand, so nothing had to recover, because nothing had failed. Once with a machine knocked out mid-sentence: that time the services came back up on the other machine by themselves. Almost every machine is copied every night — since September not straight onto the storage box, but through a machine that does nothing but keep copies: it re-reads what it holds to check the copies can still be opened, and each copy is sealed on the machine it came from before it reaches the box. The box holds parcels it cannot open. Two machines stay outside that arrangement. The copy-keeper cannot hold its own copy inside itself, so that one is written to the box directly; the other is held back from the nightly run until it handles its passwords the way the rest of the house does. The fire drill — restoring everything from those copies — has not been done yet. A copy that has never been restored is a hopeful copy. The building-permit rule has one deliberate exception, too: dashboards edited by hand in the smart home are written back into the record without a second pair of eyes, because losing every one of those edits on the next sync was judged the worse outcome.
What an outside look found. In September the whole thing was graded against the checklist a company would be held to. It came out at 45 points out of 132 — not close. Part of that is real and is being worked through. Part of it is the checklist asking for a second reviewer and a night shift, which a flat with one person in it cannot have and does not need. The method, what it cost, and the places where the grading itself turned out to be wrong are written up in 45 of 132. The findings themselves stay unpublished while they are open.
- 2 physical 24-core Proxmox nodes two shoebox-sized computers under the desk carry all of it
- 5 independently locked OpenTofu states five blueprints, each with its own lock, so two changes cannot collide
- 8 routed trust zones on the applied fabric eight rooms with locked doors between them; a door opens only where a rule says so
- 7 on-LAN CI runner registrations seven robots inside the apartment carry out approved changes — none of them lives in a cloud
checked 2026-09-09 against the Proxmox API, the CI runner registrations in GitLab, the declared OpenTofu state names, and the generated network model
Field notes
- The house decides, and no clock does
The smart home in this flat has no “leave” button and no bedtime on a wall clock. It derives five house states from a door, a phone and the presence sensors, and every other behaviour hangs off that one variable: the welcome light when someone comes home after dark, the lock, the air conditioning and the cameras when nobody is left, a vacuum that cleans only while the flat is empty, a bathroom fan that knows why it is running, a party that stays sound-reactive when the hub is down. This note goes through the rules and the reasons — a clock that cut a real daytime sleep short, a reminder that lit the bedroom seven times around a sleeping body, a fan stuck on boost for a day because a timer never fired — and is plain about what is not yet proven: the lock and the air conditioner have never been caught actually reacting to a real departure, and a lighting bridge still runs its own behaviours beside the hub in two rooms. As of 2026-09-08.
- 45 of 132, and what the score was worth
In September this fleet was audited against an enterprise rubric: every repository, every pipeline, the live state of both nodes, the firewalls, the storage box, the smart-home hub and every published site. It scored 45 points out of 132, with a median criterion score of 1 and five of nine critical rows failing. This note is about the method, the cost — seventy-two and a half million tokens measured across 358 agent runs, plus two passes whose accounting is missing entirely — and about the part worth more than the number: what the audit got wrong about itself. One in eight findings the first pass wrote down did not survive being re-read. Of 86 critical findings re-checked against live state, one was simply false. And the headline verdict was an artefact of the rubric, which asks for a second reviewer and an on-call rota that a one-person household fails by construction. As of 2026-09-08.
- The config that deploys itself
One service in this apartment datacenter is not deployed by CI. The smart-home hub fetches the reviewed branch itself, merges it, runs Home Assistant’s own configuration check against the merged tree, and resets back to its last-good commit if the check fails — or if the check cannot run at all. In exchange, the running machine may commit its interface edits straight to that protected branch, unreviewed. This note is about that trade and the controls that make it survivable: a branch nobody can rewrite, a gate that fails closed, and a commit path that refuses a secret-shaped file before the commit exists. The last one exists because ignoring files was not enough. It is also honest about what the pipeline cannot prove: no automation is tested, no firmware is compiled, and much of the running instance lives in storage git never sees. As of 2026-09-08.
- Four radios, and where local stops
Four radios carry the devices in this flat, and each is good at something the others are not. This note counts them: what each one actually carries, the devices whose firmware is built in the flat — nine built nodes, two air purifiers and, since September, the reader sitting on the electricity meter — and what measuring a radar taught about what it can and cannot see. It covers how the household’s electricity is measured too — off the utility meter’s own optical port now, with the per-phase clamps demoted to a cross-check — and the written rule against counting the same watt twice. And it is honest about the seam. Several bridges exist only to keep bought hardware useful without the vendor’s cloud, two of them running firmware written here after the manufacturer’s servers went dark. But a lighting bridge still runs its own behaviours on a wall clock beside the hub, and the Amazon Echo units in the flat are cloud devices carrying the household’s actual daily voice traffic. The local speech pipeline really is local. The house as a whole is not. As of 2026-09-08.
- What runs, and why
A tour of the services in the apartment datacenter, sorted by what they are for rather than by vendor — with the reason each one is there and the things that were deliberately left out. This is what runs as of 2026-09-08, not a recommendation; every guest named here was seen running on the Proxmox API on that date, and every container comes from a compose file in git.
- Backups: three copies, one missing proof
The apartment datacenter measured against 3-2-1: what is backed up, where it lands, what watches it, and the gap — a full restore drill that has not happened yet. The backup that silently stopped for thirteen days is the reason the monitoring exists. Since September the archives go to a dedicated backup server that deduplicates them, re-reads them to prove they are still readable, and takes them encrypted, so the storage box underneath holds copies it cannot open — which moves the hardest open question from ciphertext to who holds the key. As of 2026-09-08.
- The apartment datacenter
How one person runs a private datacenter: git records intent, CI gates every infrastructure change, AI agents do the typing — and a human keeps merge and apply authority. What is live, what is target, and why the design ended up this way. Checked against the running system on 2026-09-08; what is planned is called planned.