talos-ethernet-config

name	talos-ethernet-config
description	EthernetConfig is a separate top-level Talos machine config document, not a nested field under machine.network.interfaces. Use when configuring NIC ring buffers, channels, or features on Talos nodes.
when_to_use	Trigger phrases: "ring buffer", "NIC tuning", "ethtool", "EthernetConfig", "packet drops", "e1000e", "NIC configuration", "ethernet rings".

Talos EthernetConfig

EthernetConfig is a specific case of the general Talos multi-document config pattern. For the full picture (edit decision map, strategic merge patches, adding any document kind), see the talos-config-editing skill.

The Trap

ethernetConfig does not nest under machine.network.interfaces[]. This fails:

# WRONG — causes "unknown keys found during decoding"
machine:
  network:
    interfaces:
      - interface: eth0
        ethernetConfig:       # ← does not exist here
          rings:
            rx: 4096

Correct Format

EthernetConfig is a standalone document appended after the main v1alpha1 doc:

---
apiVersion: v1alpha1
kind: EthernetConfig
name: eth0
rings:
  rx: 4096
  tx: 4096

Repo Pattern

Add a template file and append it in the generate task — same pattern as extension-nut-client.yaml:

1. Create provision/talos/templates/ethernet-rings.yaml:

---
apiVersion: v1alpha1
kind: EthernetConfig
name: eth0
rings:
  rx: 4096
  tx: 4096

2. Append it in .taskfiles/talos/Taskfile.yaml for controlplane nodes:

envsubst < templates/extension-nut-client.yaml >> /tmp/talos-patched.yaml
cat templates/ethernet-rings.yaml >> /tmp/talos-patched.yaml   # ← add this line
mv /tmp/talos-patched.yaml clusterconfig/home-{{.ITEM}}.yaml

Check Supported Values First

Before setting ring sizes, verify hardware limits:

TALOSCONFIG=provision/talos/clusterconfig/talosconfig
talosctl -n <node-ip> --talosconfig $TALOSCONFIG get ethernetstatus eth0 -o yaml \
  | grep -A 6 "rings:"

Look for rx-max and tx-max. The Intel I219-LM (e1000e) on Lenovo M720q supports rx-max: 4096, tx-max: 4096 with a default of 256.

Other EthernetConfig Fields

Field	ethtool equivalent	Purpose
rings.rx / rings.tx	ethtool -G	Ring buffer size
channels	ethtool -L	RX/TX channel count
features	ethtool -K	Driver feature flags
wakeOnLAN	ethtool -s wol	Wake-on-LAN modes