#Configuring Multi-NIC Virtual Machine

#Create Secondary Network

1. Create NetworkAttachmentDefinition

   Execute the following command on the cluster control node:

   Command

   Example

   cat << EOF | kubectl create -f -
   apiVersion: 'k8s.cni.cncf.io/v1'
   kind: NetworkAttachmentDefinition
   metadata:
     name: <name>
     namespace: <namespace>
   spec:
     config: '{
       "cniVersion": "0.3.0",
       "type": "kube-ovn",
       "server_socket": "/run/openvswitch/kube-ovn-daemon.sock",
       "provider": "<provider>"
       }'
   EOF

   cat << EOF | kubectl create -f -
   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"
       }'
   EOF

   Parameters:

   • name: The name of NetworkAttachmentDefinition.
   • namespace: The namespace of NetworkAttachmentDefinition, Must use the same namespace as the virtual machine.
   • provider: The <name>.<namespace>.ovn of the current NetworkAttachmentDefinition. Kube-OVN will use this information to find the corresponding Subnet resource. Note that the suffix must be set to ovn.

2. Create a Kube-OVN Subnet

   If using Kube-OVN as a secondary network interface, the provider should be set to the corresponding NetworkAttachmentDefinition's <name>.<namespace>.ovn, and must end with the ovn suffix.

   Execute the following command on the cluster control node:

   Command

   Example

   cat << EOF | kubectl create -f -
   apiVersion: kubeovn.io/v1
   kind: Subnet
   metadata:
     name: <name>
   spec:
     protocol: IPv4
     enableDHCP: true
     provider: <provider>
     cidrBlock: <cidrBlock>
     gateway: <gateway>
     excludeIps:
     - <excludeIps>
   EOF

   cat << EOF | kubectl create -f -
   apiVersion: kubeovn.io/v1
   kind: Subnet
   metadata:
     name: attachnet
   spec:
     protocol: IPv4
     enableDHCP: true
     provider: attachnet.default.ovn
     cidrBlock: 172.17.0.0/16
     gateway: 172.17.0.1
     excludeIps:
     - 172.17.0.0..172.17.0.10
   EOF

   Parameters:

   • name: The name of subnet.
   • provider: The provider of NetworkAttachmentDefinition.
   • cidrBlock: The subnet cidr.
   • gateway: The gateway address.
   • excludeIps: The set reserved IP will not be automatically allocated. For example, it can be used as the IP address for computing components' fixed IP.

#Create a Multi-NIC Virtual Machine

1. Create Virtual Machine via UI

2. Switch to YAML view and add another nic to virtual machine

   Add new interface under spec.template.spec.domain.devices.interfaces

   Add new network under spec.template.spec.networks

   spec:
     template:
       spec:
         domain:
           devices:
             interfaces:
             - bridge: {}
               name: default
             # new interface
             - bridge: {}
               name: dyniface1
         networks:
         - name: default
           pod: {}
         # new network
         - multus:
             networkName: <networkName>
           name: dyniface1

   The networkName is the name of NetworkAttachmentDefinition.

#Configure Network For New NIC

After the virtual machine starts, you need to enter the virtual machine and manually configure the network for the newly added nic.

#Hotplug Network Interfaces

Hotplugging and unplugging network interfaces into a running Virtual Machine is supported

Hotplug is supported for interfaces using the virtio model connected through bridge binding or SR-IOV binding.

Hot-unplug is supported only for interfaces connected through bridge binding.

1. Adding an interface to a running VM

   Use kubectl edit to modify the virtual machine's YAML configuration

    spec:
      template:
        spec:
          domain:
            devices:
              interfaces:
              - bridge: {}
                name: default
              # new interface
              - bridge: {}
                name: dyniface1
          networks:
          - name: default
            pod: {}
          # new network
          - multus:
              networkName: <networkName>
            name: dyniface1   

2. Removing an interface from a running VM

   Use kubectl edit to modify the virtual machine's YAML configuration

   spec:
     template:
       spec:
         domain:
           devices:
             interfaces:
             - bridge: {}
               name: default
             # set the interface state to absent
             - bridge: {}
               name: dyniface1
               state: absent
         networks:
         - name: default
           pod: {}
         # new network
         - multus:
             networkName: <networkName>
           name: dyniface1