Generic Veth Chaining

The generic veth chaining plugin enables CNI chaining on top of any CNI plugin that is using a veth device model. The majority of CNI plugins use such a model.

Validate that the current CNI plugin is using veth

  1. Log into one of the worker nodes using SSH

  2. Run ip -d link to list all network devices on the node. You should be able spot network devices representing the pods running on that node.

  3. A network device might look something like this:

    103: lxcb3901b7f9c02@if102: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
        link/ether 3a:39:92:17:75:6f brd ff:ff:ff:ff:ff:ff link-netnsid 18 promiscuity 0
        veth addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535
    
  4. The veth keyword on line 3 indicates that the network device type is virtual ethernet.

If the CNI plugin you are chaining with is currently not using veth then the generic-veth plugin is not suitable. In that case, a full CNI chaining plugin is required which understands the device model of the underlying plugin. Writing such a plugin is trivial, contact us on Slack for more details.

Create a CNI configuration to define your chaining configuration

Create a chaining.yaml file based on the following template to specify the desired CNI chaining configuration:

apiVersion: v1
kind: ConfigMap
metadata:
  name: cni-configuration
  namespace: kube-system
data:
  cni-config: |-
    {
      "name": "generic-veth",
      "cniVersion": "0.3.1",
      "plugins": [
        {
          "type": "XXX",
          [...]
        },
        {
          "type": "cilium-cni"
        }
      ]
    }

Deploy the ConfigMap:

kubectl apply -f chaining.yaml

Deploy Cilium with the portmap plugin enabled

Note

First, make sure you have Helm 3 installed.

If you have (or planning to have) Helm 2 charts (and Tiller) in the same cluster, there should be no issue as both version are mutually compatible in order to support gradual migration. Cilium chart is targeting Helm 3 (v3.0.3 and above).

Setup Helm repository:

helm repo add cilium https://helm.cilium.io/

Deploy Cilium release via Helm:

helm install cilium cilium/cilium --version 1.8.1 \
  --namespace=kube-system \
  --set global.cni.chainingMode=generic-veth \
  --set global.cni.customConf=true \
  --set global.cni.configMap=cni-configuration \
  --set global.tunnel=disabled \
  --set global.masquerade=false