XQuartz: Can't Open Display Mac OS

Question

While trying to follow these SO instructions for getting a simple Xeyes application running from within a Docker container on a Mac (10.15.5) using XQuartz, this is what I get:

$ docker run -it -e DISPLAY="${IP}:0" -v /tmp/.X11-unix:/tmp/.X11-unix so_xeyes

/work # xeyes Error: Can't open display: 192.168.1.9:0

---

Here are the steps to reproduce:

$ brew install --cask xquartz

Dockerfile:

# Base Image
FROM alpine:latest

RUN apk update && \
    apk add --no-cache xeyes

# Set a working directory
WORKDIR /work

# Start a shell by default
CMD ["ash"]

Build image with:

$ docker build -t so_xeyes .

And run the Docker Container/xeyes with this:

# Set your Mac IP address
IP=$(/usr/sbin/ipconfig getifaddr en0)
echo $IP
192.168.1.9

# Allow connections from Mac to XQuartz
/opt/X11/bin/xhost + "$IP"
192.168.1.9 being added to access control list

# Run container
docker run -it -e DISPLAY="${IP}:0" -v /tmp/.X11-unix:/tmp/.X11-unix so_xeyes

When inside the container, type: xeyes

BUT, I get the following error: Error: Can't open display: 192.168.1.9:0

Does anyone have an idea how I can resolve this or to investigate further?

Answer 1

@MarkSetchell gave me a hint with suggesting I needed to modify the XQuartz Preferences > Security...

But, even after selecting "Allow connections from network clients", it still didn't work.

Then I found a Gist that gave me a little more information here because someone commented that after they made the change, they needed to reboot their Mac (again): https://gist.github.com/cschiewek/246a244ba23da8b9f0e7b11a68bf3285

So, after I made the change AND rebooted my Mac, it worked!

Thanks for guiding me to the final answer!

ALSO NOTE: You do NOT need to volume mount the .X11 directory for this to work:

docker run -it -e DISPLAY="${IP}:0" so_xeyes

Answer 2

By default, X11 does not listen over TCP/IP. You can enable that if you want in Settings, but I don't think it's necessary here. Docker should be able to route traffic to the unix domain socket setup by launchd for DISPLAY (eg: /private/tmp/com.apple.launchd.jTIfZplv7A/org.xquartz:0).

If that doesn't work, you should reach out to Docker to add support for that as it's much preferred to using TCP for X11 traffic.