Configure kube-ovn network to support pods with multiple NICs (Alpha)

Add multiple network interfaces to Pods using Multus CNI. Use Kube-OVN network’s Subnet and IP CRD for advanced IP management, including subnet management, IP reservation, random allocation, and fixed allocation.

Install multus cni

1. Clone the code:

   git clone https://github.com/k8snetworkplumbingwg/multus-cni.git

2. Enter the directory:

   cd multus-cni/deployments

3. Using multus resources:

   kubectl apply -f multus-daemonset.yml

Creating a Subnet

1. Create a subnet named attachnet using the example provided in network-attachment-definition.yml.

   Caution: The provider format in the configuration should be <NAME>.<NAMESPACE>.ovn, where <NAME> and <NAMESPACE> refer to the name and namespace of the NetworkAttachmentDefinition CR, respectively.

   apiVersion: "k8s.cni.cncf.io/v1"
   kind: NetworkAttachmentDefinition
   metadata:
     name: attachnet
     namespace: default
   spec:
     config: '{
         "cniVersion": "0.3.0",
         "type": "kube-ovn",
         "server_socket": "/run/openvswitch/kube-ovn-daemon.sock",
         "provider": "attachnet.default.ovn"
       }'

   Apply resources after creation.

   kubectl apply -f network-attachment-definition.yml

2. Use the following example to create a Kube-ovn subnet for the second network card: subnet.yml.

   Caution:

   • spec.provider must be consistent with the provider in NetworkAttachmentDefinition.

   • If an Underlay subnet is needed, set the spec.vlan of the subnet to the name of the VLAN CR that needs to be used. Other subnet parameters can be configured as needed.

   apiVersion: kubeovn.io/v1
   kind: Subnet
   metadata:
     name: subnet1
   spec:
     cidrBlock: 172.170.0.0/16
     provider: attachnet.default.ovn

   Apply resources after creation.

   kubectl apply -f subnet.yml

Create pod configure multiple nics

1. Create a pod based on the following example.

   Caution:

   • The metadata.annotations field must include a key-value pair of k8s.v1.cni.cncf.io/networks=default/attachnet, where the value is in the format of <NAMESPACE>/<NAME>, where <NAMESPACE> and <NAME> are the namespace and name of the NetworkAttachmentDefinition CR.

   • If the pod requires three network interfaces, configure the value of k8s.v1.cni.cncf.io/networks as default/attachnet,default/attachnet2.

   apiVersion: v1
   kind: Pod
   metadata:
     name: pod1
     annotations:
       k8s.v1.cni.cncf.io/networks: default/attachnet
   spec:
     containers:
     - name: web
       image: nginx:latest
       ports:
       - containerPort: 80

2. After the Pod is successfully created, use the command kubectl exec pod1 -- ip a to view the IP address of the Pod.

• Verify the creation of dual network cards

  

Other features

• Fixed IP: If you need to fix the IP of the primary network card (first network card), the method is the same as using a fixed IP for a single network card, that is, add the Annotation ovn.kubernetes.io/ip_address=<IP> to the Pod. If you need to fix the IP of the secondary network card (second network card or other network card), the basic method is the same as the primary network card, except that the ovn in the Annotation Key is replaced with the provider of the corresponding NetworkAttachmentDefinition. For example: attachnet.default.ovn.kubernetes.io/ip_address=172.170.0.101.

• Additional routing: Starting from version 1.8.0, Kube-OVN supports configuring additional routing for secondary network cards. To use it, add the routers field to the config in the NetworkAttachmentDefinition and fill in the required routes. An example is shown below:

  apiVersion: "k8s.cni.cncf.io/v1"
  kind: NetworkAttachmentDefinition
  metadata:
    name: attachnet
    namespace: default
  spec:
    config: '{
        "cniVersion": "0.3.0",
        "type": "kube-ovn",
        "server_socket": "/run/openvswitch/kube-ovn-daemon.sock",
        "provider": "attachnet.default.ovn",
        "routes": [
          {
            "dst": "19.10.0.0/16"
          },
          {
            "dst": "19.20.0.0/16",
            "gw": "19.10.0.1"
          }
        ]
      }'