1. installed MM server docker container (as per https://github.com/bastilimbach/docker-MagicMirror) . It works fine and accessible through browser at 172.17.0.1 and at localhost.
2. installed MM and through automatic installation

bash -c "$(curl -sL https://raw.githubusercontent.com/MichMich/MagicMirror/master/installers/raspberry.sh)"

3. run MM client according to the manual:

npm start && node clientonly --address 172.17.0.1 --port 8080

Here is the log

pi@raspberrypi:~/MagicMirror $ npm start && node clientonly --address 172.17.0.1 --port 8080

> magicmirror@2.7.1 start /home/pi/MagicMirror
> sh run-start.sh

Starting MagicMirror: v2.7.1
Loading config ...
Loading module helpers ...
No helper found for module: alert.
Initializing new module helper ...
Module helper loaded: updatenotification
No helper found for module: clock.
Initializing new module helper ...
Module helper loaded: calendar
No helper found for module: compliments.
No helper found for module: currentweather.
No helper found for module: weatherforecast.
Initializing new module helper ...
Module helper loaded: newsfeed
All module helpers loaded.
Starting server on port 8080 ... 
You're using a full whitelist configuration to allow for all IPs
Server started ...
Connecting socket for: updatenotification
Connecting socket for: calendar
Starting node helper for: calendar
Connecting socket for: newsfeed
Starting module: newsfeed
Sockets connected & modules started ...
Whoops! There was an uncaught exception...
{ Error: listen EADDRINUSE 0.0.0.0:8080
    at Server.setupListenHandle [as _listen2] (net.js:1330:14)
    at listenInCluster (net.js:1378:12)
    at doListen (net.js:1492:7)
    at process._tickCallback (internal/process/next_tick.js:63:19)
    at Function.Module.runMain (internal/modules/cjs/loader.js:755:11)
    at startup (internal/bootstrap/node.js:241:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:579:3)
  errno: 'EADDRINUSE',
  code: 'EADDRINUSE',
  syscall: 'listen',
  address: '0.0.0.0',
  port: 8080 }
MagicMirror will not quit, but it might be a good idea to check why this happened. Maybe no internet connection?
If you think this really is an issue, please open an issue on GitHub: https://github.com/MichMich/MagicMirror/issues
Launching application.
^CShutting down server...

pi@raspberrypi:~/MagicMirror $

config.js is configured as the following:

var config = {
	address: "0.0.0.0", // Address to listen on, can be:
	                      // - "localhost", "127.0.0.1", "::1" to listen on loopback interface
	                      // - another specific IPv4/6 to listen on a specific interface
	                      // - "", "0.0.0.0", "::" to listen on any interface
	                      // Default, when address config is left out, is "localhost"
	port: 8080,
	ipWhitelist: [], // Set [] to allow all IP addresses
	                                                       // or add a specific IPv4 of 192.168.1.5 :
	                                                       // ["127.0.0.1", "::ffff:127.0.0.1", "::1", "::ffff:192.168.1.5"],
	                                                       // or IPv4 range of 192.168.3.0 --> 192.168.3.15 use CIDR format :
	                                                       // ["127.0.0.1", "::ffff:127.0.0.1", "::1", "::ffff:192.168.3.0/28"],

Could anyone tell me what should i look at?
I need to run both (1) MM server in a docker container and (2) MM client at the same Raspberry.