Flannel — Commands & Recipes¶

Installation¶

# Install Flannel on K8s (standard)
kubectl apply -f https://github.com/flannel-io/flannel/releases/latest/download/kube-flannel.yml

# Install with custom CIDR
kubectl apply -f - <<EOF
kind: ConfigMap
apiVersion: v1
metadata:
  name: kube-flannel-cfg
  namespace: kube-flannel
data:
  net-conf.json: |
    {
      "Network": "10.244.0.0/16",
      "EnableIPv6": false,
      "Backend": {
        "Type": "vxlan"
      }
    }
EOF

Backend Configuration¶

// VXLAN (default)
{ "Type": "vxlan" }

// host-gw (best performance, requires same L2)
{ "Type": "host-gw" }

// WireGuard (encrypted)
{ "Type": "wireguard" }

Diagnostics¶

# Check flannel pods
kubectl get pods -n kube-flannel

# View subnet allocation
kubectl get nodes -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.spec.podCIDR}{"\n"}{end}'

# Flannel logs
kubectl logs -n kube-flannel -l app=flannel -f

# Check VXLAN interface
ip -d link show flannel.1

# Check routes
ip route show | grep flannel

Sources¶

Flannel Troubleshooting