---
name: "flannel-overlay-cni-networking"
description: "Configure simple, minimal overlay IPv4 networking for small-scale Kubernetes and K3s clusters."
metadata:
  author: "Flannel"
  version: "1.0.0"
  runtime_compatibility:
    - "codex"
    - "claude-code"
    - "cursor"
    - "windsurf"
triggers:
  - "configure flannel vxlan"
  - "switch flannel to host-gw"
  - "troubleshoot flannel cni"
permissions:
  fs_read: true
  fs_write: "workspace"
  shell_exec: false
  net_access: false
---

# Flannel Lightweight Overlay CNI Networking

Administers Flannel CNI: configuring VXLAN vs host-gw backends, subnet allocation per node, troubleshooting packet loss, and configuring Flannel on edge K3s deployments.

## When to Invoke
Invoke this skill whenever you need to:
- configure flannel vxlan
- switch flannel to host-gw
- troubleshoot flannel cni

## Execution SOP & Rules
1. Configure net-conf.json in flannel ConfigMap specifying Network CIDR and Backend Type (vxlan or host-gw).
2. Ensure host MTU is correctly detected; adjust ifneeded in flannel daemonset args (--iface=eth0).
3. Verify interface creation: ip a show flannel.1 on all cluster nodes.
4. Test pod-to-pod cross-node ping to confirm ARP and route table propagation.

## Verification Checklist
- Run local linting, syntax validation, and type-checks before reporting completion.
- Ensure all created or modified files adhere to workspace boundaries and avoid uncommitted secrets.
- Verify tests or build commands exit cleanly with return code 0.