OpenStack driver: define multiple networks and select floating point network

[Turmio]

Description

This PR adds support for OpenStack environment where access to multiple networks is required. Our use case is to use Docker Machine to auto scale GitLab runners in environment where runners are controlled from internal network and runner VM has access to other network(s).

Related issue(s)

[keviiin38]

This PR adds support for OpenStack environment where access to multiple networks is required. Our use case is to use Docker Machine to auto scale GitLab runners in environment where runners are controlled from internal network and runner VM has access to other network(s).

Very useful feature ! I've the exact same use-case, how did you manage this for the moment @Turmio ?

[Turmio]

Hi @keviiin38!

Actually I have build binaries in GitLab: https://gitlab.com/Turmio/machine
Seems like artifacts are already removed. I could rebase this PR to latest master and rebuild binaries for you.

We use this version of docker machine to auto scale GitLab runners. Since golang builds single file binary, we just put binary to /usr/bin and configured gitlab runner to use openstack with these new switches.

[Turmio]

Oh, Circle CI config isn't valid anymore. GitLab config seems to be fine: https://gitlab.com/Turmio/machine/-/pipelines/186178953
If GitLab is not familiar to you, artifacts can be download from repository main page, from pipelines page or from individual job page (eg. linux amd64 job).

[keviiin38]

Hello @Turmio !

Thanks for the explanation, got your PR working by just applying your patch locally (without Circle CI modification) and rebuilding the binary using Golang ! Working perfectly !

If you are okay, can I submit a MR on the "official" forked version of Docker Machine from Gitlab (here), with your changes on this PR ?

[Turmio]

@keviiin38 thanks! I did not know about "official" forked version. I made MR myself yesterday.