#!/bin/bash
# Watchdog: restart k3s if flannel.1 interface is missing.
# Runs via systemd timer every 60s.

# Only act if k3s is running but flannel.1 is gone
K3S_UNIT=$(systemctl is-active k3s 2>/dev/null)
K3S_AGENT_UNIT=$(systemctl is-active k3s-agent 2>/dev/null)

if [ "$K3S_UNIT" != "active" ] && [ "$K3S_AGENT_UNIT" != "active" ]; then
    exit 0  # k3s isn't running, nothing to do
fi

if ip link show flannel.1 >/dev/null 2>&1; then
    exit 0  # flannel is fine
fi

# flannel.1 is missing — restart the appropriate service
echo "$(date): flannel.1 missing, restarting k3s"
logger -t k3s-watchdog "flannel.1 interface missing — restarting k3s"

if [ "$K3S_UNIT" = "active" ]; then
    systemctl restart k3s
elif [ "$K3S_AGENT_UNIT" = "active" ]; then
    systemctl restart k3s-agent
fi