VNC does not work when multiple containers are run on same container network

[engageub]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

Hi Support Team,

I see that chromium container listens on port 6900 which is part of kclient (kasm) apart from default http and https custom ports.
Could you please provide support to run multiple containers on same container network. The following error is being shown while running the second container.

Please find below the error messages in the container.

Error messages in the container:
Node.js v18.17.1
Obt-Message: Xinerama extension is not present on the server
Openbox-Message: A window manager is already running on screen 0
_XSERVTransSocketUNIXCreateListener: ...SocketCreateListener() failed
_XSERVTransMakeAllCOTSServerListeners: server already running
(EE)
Fatal server error:
(EE) Cannot establish any listening sockets - Make sure an X server isn't already running(EE)
node:events:492
throw er; // Unhandled 'error' event
^

Error: listen EADDRINUSE: address already in use :::6900
at Server.setupListenHandle [as _listen2] (node:net:1751:16)
at listenInCluster (node:net:1799:12)
at Server.listen (node:net:1887:7)
at Object. (/kclient/index.js:184:6)
at Module._compile (node:internal/modules/cjs/loader:1256:14)
at Module._extensions..js (node:internal/modules/cjs/loader:1310:10)
at Module.load (node:internal/modules/cjs/loader:1119:32)
at Module._load (node:internal/modules/cjs/loader:960:12)
at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
at node:internal/main/run_main_module:23:47
Emitted 'error' event on Server instance at:
at emitErrorNT (node:net:1778:8)
at process.processTicksAndRejections (node:internal/process/task_queues:82:21) {
code: 'EADDRINUSE',
errno: -98,
syscall: 'listen',
address: '::',
port: 6900
}

Thank you

Expected Behavior

Should run the same as first container without errors and should have unique port numbers or an option where all internal port numbers of KASM can be changed.

Steps To Reproduce

sudo docker run --name tuncontainer  --restart=always -e PROXY="127.0.0.1:2345" -v '/dev/net/tun:/dev/net/tun' --cap-add=NET_ADMIN  -d xjasonlyu/tun2socks:v2.5.0
sudo docker run  -d --name chromecontainer1 --network=container:tuncontainer  -e TZ=Etc/UTC  -e CHROME_CLI="https://yahoo.com" --security-opt seccomp=unconfined --shm-size="1gb" lscr.io/linuxserver/chromium:latest
sudo docker run  -d --name chromecontainer2 --network=container:tuncontainer  -e TZ=Etc/UTC -e CUSTOM_PORT=3500  -e CUSTOM_HTTPS_PORT=3501 -e CHROME_CLI="https://google.com" --security-opt seccomp=unconfined --shm-size="1gb" lscr.io/linuxserver/chromium:latest

After running the above three commands, look into the logs of container1 and container2.

sudo docker container logs chromecontainer1
sudo docker container logs chromecontainer2

You will find that container2 does not start due to conflicting ports and display numbers.

Thank you

Environment

Docker version 24.0.5, build 24.0.5-0ubuntu1~22.04.1

CPU architecture

x86-64

Docker creation

sudo docker run --name tuncontainer  --restart=always -e PROXY="127.0.0.1:2345" -v '/dev/net/tun:/dev/net/tun' --cap-add=NET_ADMIN  -d xjasonlyu/tun2socks:v2.5.0
sudo docker run  -d --name chromecontainer1 --network=container:tuncontainer  -e TZ=Etc/UTC  -e CHROME_CLI="https://yahoo.com" --security-opt seccomp=unconfined --shm-size="1gb" lscr.io/linuxserver/chromium:latest
sudo docker run  -d --name chromecontainer2 --network=container:tuncontainer  -e TZ=Etc/UTC -e CUSTOM_PORT=3500  -e CUSTOM_HTTPS_PORT=3501 -e CHROME_CLI="https://google.com" --security-opt seccomp=unconfined --shm-size="1gb" lscr.io/linuxserver/chromium:latest

After running the above three commands, look into the logs of container1 and container2.

sudo docker container logs chromecontainer1
sudo docker container logs chromecontainer2

You will find that container2 does not start due to conflicting ports and display numbers.

Thank you

### Container logs

```bash
_XSERVTransMakeAllCOTSServerListeners: server already running
(EE)
Fatal server error:
(EE) Cannot establish any listening sockets - Make sure an X server isn't already running(EE)
Obt-Message: Xinerama extension is not present on the server
Openbox-Message: A window manager is already running on screen 0
_XSERVTransSocketUNIXCreateListener: ...SocketCreateListener() failed
_XSERVTransMakeAllCOTSServerListeners: server already running
(EE)
Fatal server error:
(EE) Cannot establish any listening sockets - Make sure an X server isn't already running(EE)
Obt-Message: Xinerama extension is not present on the server
Openbox-Message: A window manager is already running on screen 0
Obt-Message: Xinerama extension is not present on the server
Openbox-Message: A window manager is already running on screen 0
_XSERVTransSocketUNIXCreateListener: ...SocketCreateListener() failed
_XSERVTransMakeAllCOTSServerListeners: server already running
(EE)
Fatal server error:
(EE) Cannot establish any listening sockets - Make sure an X server isn't already running(EE)
_XSERVTransSocketUNIXCreateListener: ...SocketCreateListener() failed
_XSERVTransMakeAllCOTSServerListeners: server already running
(EE)
Fatal server error:
(EE) Cannot establish any listening sockets - Make sure an X server isn't already running(EE)
Obt-Message: Xinerama extension is not present on the server
Openbox-Message: A window manager is already running on screen 0
_XSERVTransSocketUNIXCreateListener: ...SocketCreateListener() failed
_XSERVTransMakeAllCOTSServerListeners: server already running
(EE)
Fatal server error:
(EE) Cannot establish any listening sockets - Make sure an X server isn't already running(EE)
node:events:492
      throw er; // Unhandled 'error' event
      ^

Error: listen EADDRINUSE: address already in use :::6900
    at Server.setupListenHandle [as _listen2] (node:net:1751:16)
    at listenInCluster (node:net:1799:12)
    at Server.listen (node:net:1887:7)
    at Object.<anonymous> (/kclient/index.js:184:6)
    at Module._compile (node:internal/modules/cjs/loader:1256:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1310:10)
    at Module.load (node:internal/modules/cjs/loader:1119:32)
    at Module._load (node:internal/modules/cjs/loader:960:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
    at node:internal/main/run_main_module:23:47
Emitted 'error' event on Server instance at:
    at emitErrorNT (node:net:1778:8)
    at process.processTicksAndRejections (node:internal/process/task_queues:82:21) {
  code: 'EADDRINUSE',
  errno: -98,
  syscall: 'listen',
  address: '::',
  port: 6900
}

Node.js v18.17.1
_XSERVTransSocketUNIXCreateListener: ...SocketCreateListener() failed
_XSERVTransMakeAllCOTSServerListeners: server already running
(EE)
Fatal server error:
(EE) Cannot establish any listening sockets - Make sure an X server isn't already running(EE)
Obt-Message: Xinerama extension is not present on the server
Openbox-Message: A window manager is already running on screen 0

[github-actions]

Thanks for opening your first issue here! Be sure to follow the relevant issue templates, or risk having this issue marked as invalid.

[j0nnymoe]

As you were told on discord, this isn't a supported usecase.

[engageub]

Hi @j0nnymoe ,
There is no issue with firefox docker since VNC port option is available.
Could you please add vnc ports similarly through kasm vnc.

Docker Firefox: https://github.com/jlesage/docker-firefox

Thank you

[j0nnymoe]

You're comparing an apple to an orange.

[engageub]

I had a look into the docker container.
The port 6900 is hardcoded in the following path /kclient/index.js
If there is something that can be done further it has to be followed up with kasmvnc team.

// Spin up application on 6900
app.use(SUBFOLDER, baseRouter);
http.listen(6900);

Thank you

[aptalca]

https://www.linuxserver.io/blog/2019-09-14-customizing-our-containers

https://www.linuxserver.io/blog/routing-docker-host-and-container-traffic-through-wireguard#routing-a-containers-traffic-through-the-wireguard-container-via

[TheSamDickey]

Wow it's mind-boggling that not allowing users to modify the hardcoded port number is such a massive problem for these developers to solve. I'm glad they feel cool about themselves!

I will no longer use this container as it will not function in the docker network I have it configured in. It conflicts with another container sharing the same port. Thanks for pointing out the firefox image, so far 30 seconds later it works without issue.

Crazy how power-hungry and delusional some people are. "Comparing an apple to an orange" "Not a supported use case". It's enabling config for changing a port number lmao. Crazy stuff guys

[Roxedus]

Lots have changed in the last two years, the env you want is mentioned in the readme.

[Roxedus]

Also worth noting that the apples to oranges statement is for vnc vs kasmVNC, which doesn't behave the same way, and are incompatible with viewers following the vnc spec.

[engageub]

The issue was solely due to conflicting ports. The internal build process is not relevant in this case; however, the option to modify the port via an environment variable or configuration setting was not provided.