Selecting the Host NIC, MTU, and Traffic Mirrors

If the host machine has multiple NICs, Kube-OVN selects the NIC of the default route as the NIC for cross-node communication between containers by default and establishes the corresponding Geneve tunnel.

To minimize additional payload overhead, during NIC creation, Kube-OVN adjusts the maximum transmission unit (MTU) of the container NIC based on the MTU of the selected host NIC, defaulting to the host MTU minus 100.

By default, Kube-OVN creates a mirror0 NIC on each node to copy the network traffic of all containers on the current node, allowing traffic analysis using tcpdump and other tools.

If you need to customize the preceding functions, you can configure cni-server in the kube-ovn.yaml file.