Change default route in docker container

If I understand the question, the problem is : when restarting a container connected to multiple bridges, how to prefer a bridge to use for default route ?

I searched available options and made some tests, I did not found any docker command line option to specify a default route or to prefer a bridge as default when the container is connected to multiple bridges. When I restart a container connected to the default bridge (bridge) and a custom bridge (your homenet), the default route is automatically set to use the default bridge (gateway 172.17.0.1). This corresponds to the behavior you describe.

Solution 1: Specify a start script in the run command that is in charge to change the default route and start the service(s) you container has to run:

docker run \
  --cap-add NET_ADMIN \ # to allow changing net settings inside the container 
  --name container1 \
  --restart always \ # restart policy
  your_image \
  /path/to/your_start_script.sh

The your_start_script.sh:

ip route del default 
ip route add default via 192.168.130.3

# here goes instructions/services your container is supposed to run

This script has to be available inside the container, it can be on a shared folder (-v option) or loaded at image building with a Dockerfile.

Note: before connecting the container to your custom bridge (docker network connect homenet container1), your_start_script.sh will crash because the default route does not correspond to any available network.

I tested to log the output of ip route inside container1 run with --restart always, after connecting it to the custom bridge it has the wanted default route.

Solution 2: Set container default route from host on container start events

docker events --filter "container=container1" |\
  awk '/container start/ { system("/path/to/route_setting.sh") }'

Where route_setting.sh contains your instructions for changing the container’s default route:

pid=$(sudo docker inspect -f '{{.State.Pid}}' container1)
sudo mkdir -p /var/run/netns
sudo ln -s /proc/$pid/ns/net /var/run/netns/$pid
sudo ip netns exec $pid ip route del default 
sudo ip netns exec $pid ip route add default via 192.168.130.3

This solution avoids giving special permissions to the container and transfers the route changing responsibility to the host.