Should we create the antrea-tun0 OVS port when using Wireguard?

[antoninbas]

While looking at #5868, I realized that we were still creating the antrea-tun0 OVS port when using Wireguard for inter-Node traffic, even though the port should not be used any more (we use Linux Wireguard tunnels, and traffic goes through the antrea-wg0 interface.

# ovs-vsctl show
75566bd4-6363-42d2-9172-a4faa89ff450
    Bridge br-int
        datapath_type: system
        Port antrea-tun0
            Interface antrea-tun0
                type: geneve
                options: {key=flow, remote_ip=flow}
        Port antrea-gw0
            Interface antrea-gw0
                type: internal
        Port coredns--3bcc0c
            Interface coredns--3bcc0c
        Port local-pa-daf9ad
            Interface local-pa-daf9ad
        Port coredns--70cbe6
            Interface coredns--70cbe6
        Port antrea-t-579008
            Interface antrea-t-579008
    ovs_version: "2.17.7"

# ovs-vsctl get interface antrea-tun0 statistics
{rx_bytes=0, rx_packets=0, tx_bytes=0, tx_packets=0}

I find it a bit confusing, and unless I am missing something, we should probably avoid creating this port altogether.

[antoninbas]

cc @xliuxu

[tnqn]

Not creating antrea-tun0 makes sense to me. If antrea-tun0 is ever used in this case, it means cross-node traffic is not encrypted, which would be a problem.

[antoninbas]

Unless I am mistaken, multi-cluster (in gateway mode) always requires antera-tun0, regardless of the traffic mode configuration, so this is a special case.