How to forward Docker for Mac to X11?

Question

Using Docker for Mac 1.12 (stable) and OS X 10.11.5 (15F34), I'm attempting to make one of my containers forward to X11.

First, I install XQuartz from my bash shell:

$ brew cask install xquartz

==> Downloading https://dl.bintray.com/xquartz/downloads/XQuartz-2.7.9.dmg
######################################################################## 100.0%
==> Verifying checksum for Cask xquartz
==> Running installer for xquartz; your password may be necessary.
==> Package installers may write to any location; options such as --appdir are ignored.
Password:
==> installer: Package name is XQuartz 2.7.9
==> installer: Installing at base path /
==> installer: The install was successful.
🍺  xquartz staged at '/usr/local/Caskroom/xquartz/2.7.9' (73M)

Then I continue with setting up XQuartz...

open -a XQuartz

In the XQuartz Preferences -> Security tab, I enable "Allow connections from network clients".

Then I am supposed to run xhost + $MY_IP_ADDRESS in my bash shell, but all I get is this error:

xhost:  unable to open display ""

In the end, all guides I'm reading says I should run my container like this:

docker run -e DISPLAY=$MY_IP_ADDRESS:0 -v /tmp/.X11-unix:/tmp/.X11-unix DOCKER_IMAGE

...but that doesn't work. In my particular container, I get this error:

... cannot connect to X server 10.0.0.131:0

What am I doing wrong?

Answer 1

Solution

After installing XQuartz you will need to restart your computer as horcle_buzz suggested; starting a new terminal session is not enough.

After a reboot you can grant access for whatever you need using the xhost command. Just be careful and understand the consequences of too permissive a rule. This other discussion has more info: Running Chromium inside Docker - Gtk: cannot open display: :0

Additional findings

Some extra things I discovered along the way:

• XQuartz must be running first:

  $ open -a XQuartz
  

• You can expose 127.0.0.1 instead of looking up your local IP (caveat emptor: I'm not an expert on the implications of this setting):

  $ xhost + 127.0.0.1
  127.0.0.1 being added to access control list
  

• You can use the special host.docker.internal identifier with docker run:

  $ docker run -e DISPLAY=host.docker.internal:0 jess/firefox
  # 🧙‍♀️ magic 🧙‍♂️
  

• At least for me, ctrl + c does not shutdown the container; I need to close the X11 window manually.
• If you quit XQuartz, you must re-auth with xhost after starting it again (the permission doesn't "stick").
• Doing it this way I didn't need to mount /tmp/.X11-unix when calling docker run.

I tested this with XQuartz 2.7.11 and Docker Desktop 2.1.0.2 on macOS Mojave (10.14.6).

Answer 2

Turns out there's a bug in XQuartz 2.7.9.

When using XQuartz 2.7.10_beta2, it works.