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USER GUIDE

Hook: routable

Purpose

Fire when an interface has full L3 connectivity — addresses and a usable path — on systemd-networkd and dhclient backends. This is the most common hook directory for “start my service when the network is actually up.”

When to use it

  • Register DNS, announce presence, or start app stacks when $ADDRESSES is meaningful
  • DHCP renewals on edge nodes (dhclient path)
  • Consume rich $JSON from systemd-networkd (MTU, DNS, routes) when emit_json: true

How to get there

  • Directory: /etc/netevd/routable.d/
  • Backends: systemd-networkd, dhclient (not NM — use Hook: manager)
  • Example env: $LINK, $ADDRESSES, $JSON (networkd), $DHCP_* (dhclient)

Operate from CLI

  1. Install the canonical first hook from Getting Started:
sudo tee /etc/netevd/routable.d/01-notify.sh >/dev/null <<'EOF'
#!/bin/bash
logger -t netevd "Interface $LINK is routable: $ADDRESSES (backend=$BACKEND)"
EOF
sudo chmod +x /etc/netevd/routable.d/01-notify.sh
  1. Enable JSON payload for networkd scripts in YAML:
sudo sed -n '/systemd_networkd:/,/networkmanager:/p' /etc/netevd/netevd.yaml
# ensure: emit_json: true under backends.systemd_networkd
netevd validate && sudo systemctl restart netevd
  1. Trigger a routable event (networkd host):
sudo networkctl renew eth0   # or reapply your .network unit
netevd events -f -i eth0 -t routable
  1. dhclient host — renew lease:
sudo dhclient -r eth0 && sudo dhclient eth0
echo "check \$DHCP_ADDRESS \$DHCP_GATEWAY in journal"
  1. Inspect script inventory:
netevd list scripts
ls -la /etc/netevd/routable.d/

  1. Empty / fail: Hook runs on carrier but not routable → script is in wrong *.d dir; $JSON empty → emit_json: false; dhclient vars missing → event fired before lease parse completes.

  2. Success: logger shows addresses; dependent service starts; netevd_script_executions_total increments (see Prometheus).