Run dbus-daemon inside Docker container

Question

I am trying to create a Docker container with a custom D-Bus bus running inside.

I configured my Dockerfile as follow:

FROM ubuntu:16.04
COPY myCustomDbus.conf /etc/dbus-1/
RUN apt-get update && apt-get install -y dbus
RUN dbus-daemon --config-file=/etc/dbus-1/myCustomDbus.conf

After building, the socket is created but it is flagged as "file", not as "socket", and I can not use it as a bus...

-rwxrwxrwx  1 root root    0 Mar 20 07:25 myCustomDbus.sock

If I remove this file and run the dbus-daemon command again in a terminal, the socket is successfully created :

srwxrwxrwx  1 root root    0 Mar 20 07:35 myCustomDbus.sock

I am not sure if it is a D-Bus problem or a docker one.

Answer 1

Instead of using the "RUN" command, you should use the "ENTRYPOINT" one to run a startup script.

The Dockerfile should look like that :

FROM ubuntu:14.04
COPY myCustomDbus.conf /etc/dbus-1/
COPY run.sh /etc/init/
RUN apt-get update && apt-get install -y dbus
ENTRYPOINT ["/etc/init/run.sh"]

And run.sh :

#!/bin/bash
dbus-daemon --config-file=/etc/dbus-1/myCustomDbus.conf --print-address

Answer 2

You should use a startup script. The "run" command is executed only when the container is created and then stopped.