run apps using audio in a docker container

Question

This question is inspired by Can you run GUI apps in a docker container?.

The basic idea is to run apps with audio and ui (vlc, firefox, skype, ...)

I was se

Answer 1

Assuming pulseaudio is installed on host and in image, one can provide pulseaudio sound over tcp with only a few steps. pulseaudio does not need to be restarted, and no configuration has to be done on host or in image either. This way it is included in x11docker, without the need of VNC or SSH:

First, find a free tcp port:

read LOWERPORT UPPERPORT < /proc/sys/net/ipv4/ip_local_port_range
while : ; do
  PULSE_PORT="`shuf -i $LOWERPORT-$UPPERPORT -n 1`"
  ss -lpn | grep -q ":$PULSE_PORT " || break
done

Get ip adress of docker daemon. I always find it being 172.17.42.1/16

ip -4 -o a | grep docker0 | awk '{print $4}'

Load pulseaudio tcp module, authenticate connection to docker ip:

PULSE_MODULE_ID=$(pactl load-module module-native-protocol-tcp port=$PULSE_PORT auth-ip-acl=172.17.42.1/16)

On docker run, create environment variable PULSE_SERVER

docker run -e PULSE_SERVER=tcp:172.17.42.1:$PULSE_PORT yourimage

Afterwards, unload tcp module. (Note: for unknown reasons, unloading this module can stop pulseaudio daemon on host):

pactl unload-module $PULSE_MODULE_ID

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Edit: How-To for ALSA and Pulseaudio in container