Add support for changes to internal Docker networking.

[WadeBarnes]

• Networking changes introduced in Docker 4.1.x and forward on Windows and MAC stop the direct use of the internal docker host IP returned by the docker run --rm --net=host eclipse/che-ip process. On Windows and MAC host.docker.internal needs to be used for internal connections between containers.

Signed-off-by: Wade Barnes wade@neoterictech.ca

[swcurran]

Does this approach work on Docker previous to 4.1? E.g. how long has host.docker.internal worked on Windows and Mac?

[WadeBarnes]

Yes this works on Docker previous to 4.1. host.docker.internal has been available on Windows and Mac for a very long time now.

host.docker.internal has been available on Windows and Mac since Docker Engine version 18.03 (March 2018). Support for host.docker.internal on Linux was introduced in version 20.10.0 (2020-12-08), but it does not run out of the box yet (from what I can tell). You need to add --add-host=host.docker.internal:host-gateway to the docker run command in order to use it. Though it would be nice if someone could test using host.docker.internal without the --add-host with a newer version of Docker for Linux to see if that's been fixed. The current version of Docker Engine is 20.10.11 (2021-11-17).

[WadeBarnes]

I did a bunch of testing and troubleshooting with Docker Engine 20.10.11 on Ubuntu and have confirmed host.docker.internal still does not work out of the box on Linux, so the docker run --rm --net=host eclipse/che-ip process is still required to get the internal address.

[swcurran]

LGTM