# services/maintenance/node-ops/titan-22-link-keeper-daemonset.yaml
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: titan-22-link-keeper
  namespace: maintenance
  labels:
    app: titan-22-link-keeper
spec:
  selector:
    matchLabels:
      app: titan-22-link-keeper
  template:
    metadata:
      labels:
        app: titan-22-link-keeper
    spec:
      hostNetwork: true
      hostPID: true
      nodeSelector:
        kubernetes.io/hostname: titan-22
      tolerations:
        - key: node.kubernetes.io/unschedulable
          operator: Exists
          effect: NoSchedule
        - key: node.kubernetes.io/not-ready
          operator: Exists
          effect: NoExecute
        - key: node.kubernetes.io/unreachable
          operator: Exists
          effect: NoExecute
        - key: node.kubernetes.io/unreachable
          operator: Exists
          effect: NoSchedule
        - key: node.kubernetes.io/disk-pressure
          operator: Exists
          effect: NoSchedule
        - key: node.kubernetes.io/memory-pressure
          operator: Exists
          effect: NoSchedule
        - key: node.kubernetes.io/pid-pressure
          operator: Exists
          effect: NoSchedule
        - key: node.kubernetes.io/network-unavailable
          operator: Exists
          effect: NoSchedule
      containers:
        - name: link-keeper
          image: bitnami/kubectl@sha256:554ab88b1858e8424c55de37ad417b16f2a0e65d1607aa0f3fe3ce9b9f10b131
          imagePullPolicy: IfNotPresent
          securityContext:
            privileged: true
            runAsUser: 0
          command:
            - /bin/bash
            - -lc
            - |
              set -u
              while true; do
                nsenter -t 1 -m -u -i -n -p -- /bin/sh -lc '
                  usb_if="enx4cea41672a87"
                  usb_mac="4c:ea:41:67:2a:87"
                  old_if="enp5s0"
                  canonical_ip="192.168.22.22"
                  gateway="192.168.22.1"
                  k3s_env="/etc/default/k3s-agent"

                  date -Is
                  if [ ! -d "/sys/class/net/${usb_if}" ]; then
                    echo "USB Ethernet interface ${usb_if} is missing"
                    exit 0
                  fi

                  detected_mac="$(cat "/sys/class/net/${usb_if}/address")"
                  if [ "${detected_mac}" != "${usb_mac}" ]; then
                    echo "refusing to configure ${usb_if}: unexpected MAC ${detected_mac}"
                    exit 0
                  fi

                  # Keep the RTL8153 firmware patch available for subsequent cold boots.
                  if ! dpkg-query -W -f="\${Status}" firmware-realtek 2>/dev/null | grep -q "install ok installed"; then
                    echo "installing firmware-realtek for ${usb_if}"
                    apt-get update
                    DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends firmware-realtek
                  fi

                  stale_swap_uuid="ccab2cd7-43fe-480d-b0a6-e567e5d7310a"
                  if [ -f /swapfile ] && grep -q -E "^UUID=${stale_swap_uuid}[[:space:]]" /etc/fstab; then
                    echo "removing stale swap UUID ${stale_swap_uuid} from /etc/fstab"
                    fstab_tmp="$(mktemp)"
                    grep -v -E "^UUID=${stale_swap_uuid}[[:space:]]" /etc/fstab >"${fstab_tmp}"
                    install -m 0644 "${fstab_tmp}" /etc/fstab
                    rm -f "${fstab_tmp}"
                  fi

                  if nmcli connection show "Wired connection 1" >/dev/null 2>&1; then
                    nmcli connection modify "Wired connection 1" connection.autoconnect no || true
                  fi
                  nmcli device disconnect "${old_if}" >/dev/null 2>&1 || true
                  ip link set "${old_if}" down || true

                  connection="$(nmcli -g GENERAL.CONNECTION device show "${usb_if}" 2>/dev/null || true)"
                  if [ -z "${connection}" ] || [ "${connection}" = "--" ]; then
                    connection="titan-22-usb-primary"
                    if ! nmcli connection show "${connection}" >/dev/null 2>&1; then
                      nmcli connection add type ethernet ifname "${usb_if}" con-name "${connection}"
                    fi
                  fi

                  nmcli connection modify "${connection}" \
                    connection.interface-name "${usb_if}" \
                    connection.autoconnect yes \
                    connection.autoconnect-priority 100 \
                    ipv4.method manual \
                    ipv4.addresses "${canonical_ip}/24" \
                    ipv4.gateway "${gateway}" \
                    ipv4.dns "${gateway}" \
                    ipv4.dns-search titan \
                    ipv6.method auto

                  if ! ip -4 address show dev "${usb_if}" | grep -q " ${canonical_ip}/24"; then
                    echo "moving the canonical node address to ${usb_if}"
                    nmcli connection up "${connection}" ifname "${usb_if}"
                  fi

                  ip link set "${usb_if}" up
                  ethtool --set-eee "${usb_if}" eee off || true

                  mkdir -p "$(dirname "${k3s_env}")"
                  env_tmp="$(mktemp)"
                  if [ -f "${k3s_env}" ]; then
                    grep -v -E "^K3S_(NODE_IP|FLANNEL_IFACE)=" "${k3s_env}" >"${env_tmp}" || true
                  fi
                  printf "K3S_NODE_IP=%s\\nK3S_FLANNEL_IFACE=%s\\n" \
                    "${canonical_ip}" "${usb_if}" >>"${env_tmp}"
                  if ! cmp -s "${env_tmp}" "${k3s_env}"; then
                    install -m 0644 "${env_tmp}" "${k3s_env}"
                    echo "updated k3s network environment"
                  fi
                  rm -f "${env_tmp}"

                  # k3s embeds kubelet; the standalone Debian unit only crash-loops.
                  systemctl disable --now kubelet.service >/dev/null 2>&1 || true

                  ethtool "${usb_if}" | sed -n "1,45p" || true
                  ip -br address show "${usb_if}" || true
                  ip -d link show flannel.1 | sed -n "1,3p" || true
                '
                sleep 60
              done