From 074f9887313cde24a9353f02a868c5e9bef22550 Mon Sep 17 00:00:00 2001
From: jenkins <brad@bstein.dev>
Date: Sat, 22 Aug 2026 20:42:51 -0300
Subject: [PATCH] node(titan-22): migrate k3s to USB ethernet

---
 .../titan-22-link-keeper-daemonset.yaml       | 90 ++++++++++++++-----
 1 file changed, 69 insertions(+), 21 deletions(-)

diff --git a/services/maintenance/node-ops/titan-22-link-keeper-daemonset.yaml b/services/maintenance/node-ops/titan-22-link-keeper-daemonset.yaml
index b4dcb6b9..42d46d4a 100644
--- a/services/maintenance/node-ops/titan-22-link-keeper-daemonset.yaml
+++ b/services/maintenance/node-ops/titan-22-link-keeper-daemonset.yaml
@@ -58,29 +58,77 @@ spec:
               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
-                  ip link set enp5s0 up || true
-                  ethtool --set-eee enp5s0 eee off || true
-                  ethtool -s enp5s0 advertise 0x020 autoneg on || true
-                  sleep 3
-
-                  stable=true
-                  for _ in 1 2 3 4 5; do
-                    if ! ethtool enp5s0 | grep -q "Link detected: yes"; then
-                      stable=false
-                    fi
-                    sleep 2
-                  done
-
-                  if [ "${stable}" != "true" ]; then
-                    echo "link not stable at 1G-only; falling back to 100M-only autoneg"
-                    ethtool -s enp5s0 advertise 0x008 autoneg on || true
-                    sleep 5
+                  if [ ! -d "/sys/class/net/${usb_if}" ]; then
+                    echo "USB Ethernet interface ${usb_if} is missing"
+                    exit 0
                   fi
 
-                  ethtool --show-eee enp5s0 || true
-                  ethtool enp5s0 | sed -n "1,45p" || true
-                  ip -br addr show enp5s0 || true
+                  detected_mac="$(cat "/sys/class/net/${usb_if}/address")"
+                  if [ "${detected_mac}" != "${usb_mac}" ]; then
+                    echo "refusing to configure ${usb_if}: unexpected MAC ${detected_mac}"
+                    exit 0
+                  fi
+
+                  if nmcli connection show "Wired connection 1" >/dev/null 2>&1; then
+                    nmcli connection modify "Wired connection 1" connection.autoconnect no || true
+                  fi
+                  nmcli device disconnect "${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 30
+                sleep 60
               done