How to change "default" docker-machine's dns settings

I know how to create a new docker-machine with dns settings

docker-machine create -d virtualbox --engine-opt dns=8.8.8.8 my_machine

But there is already a "default" virtualmachine so is there a way to change its dns?

I read online ways to do this with boot2docker, but that tool is deprecated and docker-machine has replaced it. Unfortunately, it's so new that I haven't found much online about this.

Solution

Go to ~/.docker/machine/machines/default/config.json and add your own DNS server into HostOptions/EngineOptions/Dns and restart docker machine.

{  
   "HostOptions": {
        "Driver": "",
        "Memory": 0,
        "Disk": 0,
        "EngineOptions": {
            "ArbitraryFlags": [],
            "Dns": ["192.168.99.1","8.8.8.8","8.8.4.4"], <-- set it here
            "GraphDir": ""
        }
}

Edit:

The Dns setting in config.json seems to be ignored in the new version of docker-machine. The only thing that seems to work is to add line (edit this to match your needs)

"${DOCKER_MACHINE}" ssh "${VM}" "sudo sed -i.bkp '/--label provider=virtualbox/a --dns 8.8.8.8\\\n--dns 8.8.4.4' /var/lib/boot2docker/profile && sudo /etc/init.d/docker restart"

after

yes | "${DOCKER_MACHINE}" regenerate-certs "${VM}"

in script start.sh, which is run every time Docker Quickstart Terminal is started.

Then shut down the machine (if it's running) and open a new instance of the Docker Quickstart Terminal.