Internal macvlan network overrides default gateway

[lemrouch]

I have container which needs to be connected to multiple overlay networks and one internal macvlan network.
Every time I connect the container to the macvlan network, it's default gateway will be set to non-existent default gateway.

I don't think internal networks should touch default gateway at all.

[chiragtayal]

Can you please provide the output you see?

[lemrouch]

Prepare two networks:
docker network create --driver=overlay --attachable --scope=global --ip-range=10.10.10.0/24 --subnet=10.10.10.0/24 public_net
docker network create --driver=macvlan -o parent=enp1s0 --internal --attachable --ip-range=10.10.20.0/24 --subnet=10.10.20.0/24 private_net

Run container let say with Debian:
docker run -it --rm --network=public_net debian:latest /bin/bash

Check the network in the container:
root@6c1d0c80568b:/# ip r s
default via 172.18.0.1 dev eth1
10.10.10.0/24 dev eth0 proto kernel scope link src 10.10.10.2
172.18.0.0/16 dev eth1 proto kernel scope link src 172.18.0.3

Connect the container to the macvlan internal network:
docker network connect private_net 6c1d0c80568b

Check the containet network again:
root@6c1d0c80568b:/# ip r s
default via 10.10.20.1 dev eth2
10.10.10.0/24 dev eth0 proto kernel scope link src 10.10.10.2
10.10.20.0/24 dev eth2 proto kernel scope link src 10.10.20.2
172.18.0.0/16 dev eth1 proto kernel scope link src 172.18.0.3

As you can see the container has default gateway set to 10.10.20.1 which is macvlan internal network range.

According to documentation this is not expected behavior:

When a container is connected to multiple networks, its external connectivity is provided via the first non-internal network, in lexical order.

[lemrouch]

Ping.
Anybody out there?

[selansen]

@chiragtayal PTAL.

[lemrouch]

Maybe chiragtayal is overloaded. Is there anyone else who can take a look?

[suwang48404]

@lemrouch
can you provide some insight with regard to having internal macvlan network? what is it used for?