echo6-docs/runbooks/headscale-onboard-node.md

Headscale / Tailscale — Onboard a New Node

Standard procedure to bring any new system (Proxmox host, bare-metal, VM, or LXC) onto the Echo6 tailnet.

Overview

• Control server: Headscale on Contabo — ssh root@100.64.0.1, Docker container headscale.
• Login server: https://vpn.echo6.co · Admin UI (Headplane): https://vpn.echo6.co/admin
• User/namespace: all Echo6 nodes join echo6 (user ID 1).
• MagicDNS base domain: echo6.mesh (e.g. ping data.echo6.mesh).
• Naming: lowercase, hyphens OK, no dots/underscores. Matches --hostname and the cortex SSH alias.

1. Generate a preauth key (on Contabo)

ssh root@100.64.0.1 'docker exec headscale headscale preauthkeys create --user echo6 --reusable --expiration 1h'
# If the name form errors, use the user ID: --user 1

2. Install Tailscale on the node

curl -fsSL https://tailscale.com/install.sh | sh
systemctl enable --now tailscaled

3. DNS-bootstrap drop-in (REQUIRED on LXCs, recommended everywhere)

Without this, tailscaled can't resolve vpn.echo6.co on a cold boot. Makes onboarding survive a reboot.

mkdir -p /etc/systemd/system/tailscaled.service.d
cat > /etc/systemd/system/tailscaled.service.d/dns-bootstrap.conf <<'EOF'
[Service]
ExecStartPre=/bin/sh -c "grep -q nameserver /etc/resolv.conf || echo nameserver 1.1.1.1 > /etc/resolv.conf"
EOF
systemctl daemon-reload

4. LXC containers only — TUN device prerequisite

On the Proxmox host, before starting the container (needs nesting=1,keyctl=1 features set):

pct stop <CTID>
cat >> /etc/pve/lxc/<CTID>.conf <<'EOF'
lxc.cgroup2.devices.allow: c 10:200 rwm
lxc.mount.entry: /dev/net/tun dev/net/tun none bind,create=file
EOF
pct start <CTID>

(Privileged variant: create with --unprivileged 0, use lxc.mount.entry: /dev/net dev/net none bind,create=dir.)

5. Register with Headscale

tailscale up --login-server=https://vpn.echo6.co --auth-key=<KEY> --hostname=<NAME>

• Standard nodes pass no --advertise-routes / --accept-routes / --advertise-tags.
• Add --ssh to enable Tailscale SSH.
• Always include --login-server=https://vpn.echo6.co — without it the node registers against Tailscale's public servers instead of Echo6 Headscale.
• Subnet-router exception: the mesh-bridge advertises 100.100.0.0/16 --accept-routes, then enable on Headscale (headscale routes list / routes enable -r <ID>).

6. Verify

tailscale status
tailscale ip -4
ssh root@100.64.0.1 'docker exec headscale headscale nodes list'   # confirm node + assigned 100.64.0.x

Headscale assigns the IP sequentially at registration — don't pre-assign; read it back here.

7. SSH config aliases on cortex (~/.ssh/config)

Host <alias>
    HostName <local-or-public-IP>
    User root

Host ts-<alias>
    HostName <tailscale-IP>
    User root

Most nodes use User root. Per-node exceptions exist — e.g. edge2 uses User admin + IdentityFile ~/.ssh/contabo2_ed25519 (cloud image, no root login).

8. Update inventory

• docs/hardware/environment.md — Key Servers table and Headscale Node List (bump count + "updated" line).
• docs/hardware/ip-allocation.md — Tailscale IPs section.
• CLAUDE.md cluster cheat-sheet — Proxmox hosts only.
• docs/services/services.md — once services are deployed on the node.

Worked example — edge2 (2026-06-16)

Proxmox host on Contabo. Preauth key → tailscale up --login-server=https://vpn.echo6.co --auth-key=<KEY> --hostname=edge2 → assigned 100.64.0.26 (Headscale node 42). SSH aliases edge2 / ts-edge2 use User admin + ~/.ssh/contabo2_ed25519.

Gotchas

• environment.md's Headscale Node List is the authoritative IP source — ip-allocation.md's table has gone stale before.
• A node deleted from Headscale does not get its old IP auto-reused; confirm the real next IP with headscale nodes list.
• The old ct-runbook tailscale up --authkey ... --ssh form omits --login-server — don't copy it blindly.

Checklist

[ ] Preauth key generated on Contabo (user echo6)
[ ] Tailscale installed + tailscaled enabled
[ ] DNS-bootstrap drop-in in place (LXC: required)
[ ] (LXC) TUN device added to CT config
[ ] tailscale up with --login-server=https://vpn.echo6.co --hostname=<name>
[ ] Node appears in headscale nodes list; IP captured
[ ] SSH aliases (<alias> + ts-<alias>) added on cortex and tested
[ ] Inventory updated (environment.md, ip-allocation.md, CLAUDE.md)