So I'm trying to create a network (docker network create) so that its traffic will pass through an specific physical network interface (NIC); I have two: <iface1> (internal), and <iface2> (external). I need the traffics of both NICs to be physically separated. METHOD 1: I think macvlan is the driver should use to create such network.
For most of what I found on the internet, the solutions refer to Pipework (deprecated now) and temporary docker-plugins (deprecated too).
For what most closely has helped me is this1 docker network create -d macvlan \
    --subnet 192.168.0.0/16 \
    --ip-range 192.168.2.0/24 \
    -o parent=wlp8s0.1 \
    -o macvlan_mode=bridge \
    macvlan0
 Then, in order for the container to be visible from the host, I need to do this in the host: sudo ip link add macvlan0 link wlp8s0.1 type macvlan mode bridge
sudo ip addr add 192.168.2.10/16 dev macvlan0
sudo ifconfig macvlan0 up
 Now the container and the host see each other :) BUT the container can't access the local network.
The idea, is that the container can access internet. METHOD 2: As I will use <iface2> manually, I'm ok if by default the traffic goes through <iface1>.
But no matter in which order I get the NICs up (I also tried removing the LKM for <iface2> temporarely); the whole traffic is always overtaken by the external NIC <iface2>.
And I found that it happens because the route table updates automatically at some "random" time.
In order to force the traffic to go through <iface1>, I have to (in the host): sudo route del -net <net> gw 0.0.0.0 netmask 255.0.0.0 dev <iface2>
sudo route del default <iface2>
 Now, I can verify (in several ways) that the traffic just goes through <iface1>.
But the moment that the route table updates (automatically), all traffic moves to <iface2>. Damn!
I'm sure there's a way to make the route table "static" or "persistent". EDIT (18/Jul/2018):
The main idea is to be able to access internet through a docker container using only one of two available physical network interfaces.