...
Installation is quite straight-forward, just run the following command - no further configuration is needed:
docker run --name guacd -it -d -p 4822:4822 guacamole/guacd
...
add following block to https server block in the nginx configuration file (in my case /varetc/lib/docker/volumes/reverse_proxy_conf/_data/conf.dnginx/conf.d/default.conf):
## Guacamole#location /guacamole/ { proxy_pass http://<docker-host>:8080/guacamole/; proxy_buffering off; proxy_http_version 1.1; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection $http_connection; access_log off; }
...