ip link add link eth0 name eth0.100 type vlan id 100
ip netns add testns
ip netns list
ip link set eth1 netns testns
ip netns exec testns bash
echo -eth3 > /sys/class/net/bond0123/bonding/slaves
echo -bond0123 > /sys/class/net/bonding_masters
ip route add 1.2.3.4/32 scope global \
nexthop via 10.100.100.1 weight 1 \
nexthop via 10.100.101.1 weight 1