Apache Guacamole in Docker containers: Creation of WebSocket tunnel to guacd failed - docker

Question

I installed Apache Guacamole using Docker on a CentOS 8.1 with Docker 19.03.
I followed the steps described here:
https://guacamole.apache.org/doc/gug/guacamole-docker.html
https://www.linode.com/docs/applications/remote-desktop/remote-desktop-using-apache-guacamole-on-docker/
I started the containers like this:
# mysql container
docker run --name guacamole-mysql -e MYSQL_RANDOM_ROOT_PASSWORD=yes -e MYSQL_ONETIME_PASSWORD=yes -d mysql/mysql-server
# guacd container
docker run --name guacamole-guacd -e GUACD_LOG_LEVEL=debug -d guacamole/guacd
# guacamole container
docker run --name guacamole-guacamole --link guacamole-guacd:guacd --link guacamole-mysql:mysql -e MYSQL_DATABASE=guacamole -e MYSQL_USER=guacamole -e MYSQL_PASSWORD=password -d -p 8080:8080 guacamole/guacamole
All went fine and I was able to access the Guacamole web interface on port 8080. I configured one VNC connection to another machine on port 5900. Unfortunately when I try to use that connection I get the following error in the web interface:
"An internal error has occurred within the Guacamole server, and the connection has been terminated..."
I had a look on the logs too and in the guacamole log I found this:
docker logs --tail all -f guacamole-guacamole
...
15:54:06.262 [http-nio-8080-exec-2] ERROR o.a.g.w.GuacamoleWebSocketTunnelEndpoint - Creation of WebSocket tunnel to guacd failed: End of stream while waiting for "args".
15:54:06.685 [http-nio-8080-exec-8] ERROR o.a.g.s.GuacamoleHTTPTunnelServlet - HTTP tunnel request failed: End of stream while waiting for "args".
I'm sure that the target machine (which is running the VNC server) is fine. I'm able to connect to it from both a VNC client and another older Guacamole which I installed previously (not using Docker).
My containers look ok too:
docker container ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
ad62aaca5627 guacamole/guacamole "/opt/guacamole/bin/…" About an hour ago Up About an hour 0.0.0.0:8080->8080/tcp guacamole-guacamole
a46bd76234ea guacamole/guacd "/bin/sh -c '/usr/lo…" About an hour ago Up About an hour 4822/tcp guacamole-guacd
ed3a590b19d3 mysql/mysql-server "/entrypoint.sh mysq…" 2 hours ago Up 2 hours (healthy) 3306/tcp, 33060/tcp guacamole-mysql
I connected to the guacamole-guacamole container and pinged the other two containers: guacamole-mysql and guacamole-guacd. Both look fine and reachable.
docker exec -it guacamole-guacamole bash
root#ad62aaca5627:/opt/guacamole# ping guacd
PING guacd (172.17.0.2) 56(84) bytes of data.
64 bytes from guacd (172.17.0.2): icmp_seq=1 ttl=64 time=0.191 ms
64 bytes from guacd (172.17.0.2): icmp_seq=2 ttl=64 time=0.091 ms
root#ad62aaca5627:/opt/guacamole# ping mysql
PING mysql (172.17.0.3) 56(84) bytes of data.
64 bytes from mysql (172.17.0.3): icmp_seq=1 ttl=64 time=0.143 ms
64 bytes from mysql (172.17.0.3): icmp_seq=2 ttl=64 time=0.102 ms
Looks like there is a communication issue between the guacamole itself and guacd. And this is where I'm completely stuck.
EDIT
I tried on CentOS 7 and I got the same issues.
I also tried this solution https://github.com/boschkundendienst/guacamole-docker-compose as suggested by #BatchenRegev but I got the same issue again.

Answer 1

I've been experiencing the same issues under centos.
My only difference is that I'm hosting the database on a separate machine as this is all cloud-hosted and I want to be able to destroy/rebuild the guacamole server at will.
I ended creating a docker-compose.yml file as that seemed to work better.
Other gotcha's I came across:
make sure the guacd_hostname is the actual machine hostname and not 127.0.0.1
setting Selinux to allow httpd.
sudo setsebool -P httpd_can_network_connect
My docker-compose.yml is shown below replace all {variables} with your own and update the file if you are using a sql image as well.
version: "2"
services:
guacd:
image: "guacamole/guacd"
container_name: guacd
hostname: guacd
restart: always
volumes:
- "/data/shared/guacamole/guacd/data:/data"
- "/data/shared/guacamole/guacd/conf:/conf:ro"
expose:
- "4822"
ports:
- "4822:4822"
network_mode: bridge
guacamole:
image: "guacamole/guacamole"
container_name: guacamole
hostname: guacamole
restart: always
volumes:
- "/data/shared/guacamole/guacamole/guac-home:/data"
- "/data/shared/guacamole/guacamole/conf:/conf:ro"
expose:
- "8080"
ports:
- "8088:8080"
network_mode: bridge
environment:
- "GUACD_HOSTNAME={my_server_hostname}"
- "GUACD_PORT=4822"
- "MYSQL_PORT=3306"
- "MYSQL_DATABASE=guacamole"
- "GUACAMOLE_HOME=/data"
- "MYSQL_USER=${my_db_user}"
- "MYSQL_PASSWORD=${my_db_password}"
- "MYSQL_HOSTNAME=${my_db_hostname}"

Answer 2

i have the same problem on FreeBSD 12.2 - SOLUTION
Change "localhost" hostname in
/usr/local/etc/guacamole-client/guacamole.properties
to "example"
guacd-hostname: 192.168.10.10
next: /usr/local/etc/guacamole-server/guacd.conf
[server]
bind_host = 192.168.10.10
Check /etc/guacamole/guacamole.properties i have link:
guacd-hostname: 192.168.10.10
Restart:
/usr/local/etc/rc.d/guacd restart
/usr/local/etc/rc.d/tomcat9 restart
with name "localhost" i have:
11:01:48.010 [http-nio-8085-exec-3] DEBUG o.a.g.s.GuacamoleHTTPTunnelServlet - Internal error in HTTP tunnel.
I hope it will be useful to someone else - it works for me`