when network adapter is down, it does not work

[aprossi]

dockeri works ok with existing containers while the host is connected to the network. Turning off wi-fi causes an error, e.g. (on a mac)

Fatal: QXcbConnection: Could not connect to display :0

[chbrandt]

Indeed, thanks for pointing that out.

X11 communication between the container and host routes through TCP sockets. Although I have tried to make use of unix sockets, as of today, they are not (completely) supported my docker on mac (docker-for-mac/osxfs).

In this scenario, X11 bind between container and host (dockeri and Xorg/XQuartz) need an alive network interface; we need an IP address to where the docker-machine will route X11 data.

What happens when we shut down the wi-fi interface is the loss of the IP/interface that dockeri had chosen to use for X11 routing.

One alternative I have in mind is to create a virtual network interface, associate a dummy IP to it (e.g, 198.168.1.1) and bind the X11/DISPLAY to it. In theory, this interface would never go down.

[chbrandt]

OK. I put some more reading on the subject. I will digest that in the next days, but I'll leave it here for the records and...a second reading soon.

First, a long discussion on the subject "unix sockets on MacOS & Docker", since unix sockets would be right (at least the most elegant) solution to the issue:

• Support for sharing unix sockets docker/for-mac#483

On the network side, besides the Docker network docs, there is this nice review from Mesosphere:

• https://mesosphere.com/blog/networking-docker-containers/

Regarding unix sockets -- in particular using it for X forwarding -- there are lots of posts out there about doing it on Linux; no secrets, but it is worth list some good ones:

• Lots of examples by Jessie Frazelle
• Sum up by Jean-Tiare with some extras: xauth, socat

And the link for Socat, which seems to be coming back to the scene:

• http://www.dest-unreach.org/socat/doc/socat.html