SEC.01
The playbook
The run starts read-only: the recon probes decide what happens next. The steps that follow are adapted to the distribution and state found — a real machine is rarely clean.
- 01recondistro, version and package manager (apt or dnf)
- 02reconDocker Engine + compose plugin present and running? (otherwise, docker step)
- 03reconserver already deployed (container, volume, /opt/valheim)? healthy → verify and skip; never reset a world or a save
- 04reconports 2456-2457/udp free?
- 05reconRAM ≥ 4 GB recommended and ≥ 5 GB of free disk
- 06reconactive firewall (ufw or firewalld)? a port is only opened if one is active
- 07actInstall Docker Engine + Compose (only if missing)verify
- 08actCreate the dedicated valheim user and its foldersverify
- 09actStore the server password (/opt/valheim/valheim.env)verify
- 10actStart the Valheim serververify
- 11actOpen 2456-2457/udp (only if a firewall is active)verify
- 12actThe server is readyverify
SEC.02
What it verifies
Each step ships its own check. The run only moves on when the check passes, so what the recipe reports as done is what is actually on the server.
- 01verifyInstall Docker Engine + Compose (only if missing)Verified by
systemctl is-active docker && docker compose version - 02verifyCreate the dedicated valheim user and its foldersVerified by
id -u valheim && stat -c '%U' /opt/valheim/config /opt/valheim/data - 03verifyStore the server password (/opt/valheim/valheim.env)Verified by
stat -c '%a' /opt/valheim/valheim.env && grep -c '^SERVER_PASS=' /opt/valheim/valheim.env - 04verifyStart the Valheim serverVerified by
docker inspect -f '{{.State.Status}}' valheim - 05verifyOpen 2456-2457/udp (only if a firewall is active)Verified by
ufw status 2>/dev/null | grep -cE '2456:2457'; firewall-cmd --list-ports 2>/dev/null; true - 06verifyThe server is readyVerified by
timeout 270 bash -c 'until docker logs valheim 2>&1 | grep -q "Game server connected"; do sleep 10; done' && echo ready
SEC.03
Guardrails
Non-negotiable instructions the run must respect, whatever it finds on the server.
The password must be ≥ 5 characters and not contained in the server name (Valheim refuses otherwise); it stays in /opt/valheim/valheim.env (600), never in logs. The container runs as the valheim user, not root. Never reset an existing world in /opt/valheim/config. RAM < 4 GB → warn.
SEC.04
Variables
What you choose before launching — the recipe fills in the rest.
| Name | Meaning |
|---|---|
| ${server_name} | Server name |
| ${world_name} | World name |
| ${password} | Password (≥ 5 chars) |
SEC.05
How a recipe runs in Servor
Servor is zero-knowledge: the platform cannot execute anything on its own. When you launch this recipe, a run reads the reconnaissance, plans the steps and asks for your approval. Each approved command is signed by your browser — with a key the server never sees — then relayed verbatim to the agent, which verifies the signature locally before executing.
search by intent — type “firewall”, get ufw
- 01Read-only reconnaissance before any change
- 02Every command signed by your browser, approved by you
- 03Each step verified before the run moves on, every run kept in the history
SEC.06
Deploy on Servor button
Maintain Valheim Server or a project that needs it? Put this button in your README or on your site: one click and your users install it on their own server.
SEC.07
More game servers recipes
- 01Minecraft Server (Java)Minecraft Java server (Paper, Vanilla, Fabric or Forge) under a dedicated user, as a systemd service, with the right Java.
- 02Factorio ServerDedicated Factorio server (stable release) via Docker, non-root, saves in /opt/factorio.
- 03Mumble ServerMumble (murmur) voice server from the distro packages, generated SuperUser password, started and verified.
- 04Minecraft Bedrock ServerDedicated Minecraft Bedrock server via Docker, under a dedicated user, world in /opt/bedrock.
- 05Terraria ServerDedicated Terraria (TShock) server via Docker, worlds in /opt/terraria.
Verified recipe
Run this recipe on your server
Connect a server, launch the recipe, and approve each step as Servor executes and verifies it. Free plan, no card required.