X11vnc inside Docker container takes too long to connect

Rocky Linux Tech Help
1

Hello,

I’m using selenoid and selenoid-ui on my Rocky Linux 9 server, everything looks OK, docker logs of selenoid, selenoid ui, selenoid/chrome container when started but when I create selenoid/chrome session it takes several minutes to display the session UI on selenoid UI

Basically, vnc inside docker container is on the 100% even if I maxed it out with resources, and question is - are there any privileges/firewall configuration/security configuration I should set in order to speed up vnc connecting?

and after that, after 3-5 minutes, session UI is displayed.

While waiting for the VNC connection, I inspected selenoid/chrome container and the CPU usage was on 100% by the x11vnc:

image
image993×116 21.7 KB

As soon as session UI is displayed, CPU usage drops to the normal (not 100%)

This is the case on Rocky Linux 9 server but not on Ubuntu, tried different selenoid configurations but wasn’t successful…

Configuration I’m using now:

{
    "chrome": {
        "default": "127.0",
        "versions": {
            "127.0": {
                "image": "selenoid/chrome:127.0",
                "port": "4444",
                "path": "/",
                "tmpfs": {
                    "/tmp": "size=512m"
                },
	        "env": ["ENABLE_VNC=true", "SCREEN_WIDTH=1920", "SCREEN_HEIGHT=1080", "SCREEN_DEPTH=24"],
                "shmSize" : 268435456,
                "mem": "512m",
		"cpu": "4.0"
            }
            
        }
    }
}

Selenoid logs:

2024/09/04 12:31:19 [-] [NEW_REQUEST] [unknown] [192.168.0.144]
2024/09/04 12:31:19 [-] [NEW_REQUEST_ACCEPTED] [unknown] [192.168.0.144]
2024/09/04 12:31:19 [69] [LOCATING_SERVICE] [chrome] [127.0]
2024/09/04 12:31:19 [69] [USING_DOCKER] [chrome] [127.0]
2024/09/04 12:31:19 [69] [CREATING_CONTAINER] [selenoid/chrome:127.0]
2024/09/04 12:31:19 [69] [STARTING_CONTAINER] [selenoid/chrome:127.0] [7121d69ec5613dcbb8c777a7f6aed6cdfd96f291a073670c394c40476947fdb7]
2024/09/04 12:31:19 [69] [CONTAINER_STARTED] [selenoid/chrome:127.0] [7121d69ec5613dcbb8c777a7f6aed6cdfd96f291a073670c394c40476947fdb7] [0.14s]
2024/09/04 12:31:19 [69] [SERVICE_STARTED] [selenoid/chrome:127.0] [7121d69ec5613dcbb8c777a7f6aed6cdfd96f291a073670c394c40476947fdb7] [0.31s]
2024/09/04 12:31:19 [69] [PROXY_TO] [7121d69ec5613dcbb8c777a7f6aed6cdfd96f291a073670c394c40476947fdb7] [http://172.17.0.4:4444/]
2024/09/04 12:31:19 [69] [SESSION_ATTEMPTED] [http://172.17.0.4:4444/] [1]
2024/09/04 12:31:19 [69] [SESSION_CREATED] [a12187ec49043c3abe46b15cd624a705] [1] [0.84s]
2024/09/04 12:31:22 [72] [CONTAINER_LOGS] [7121d69ec5613dcbb8c777a7f6aed6cdfd96f291a073670c394c40476947fdb7]
2024/09/04 12:31:22 [73] [VNC_ENABLED] [a12187ec49043c3abe46b15cd624a705]
2024/09/04 12:53:06 [-] [NEW_REQUEST] [unknown] [192.168.0.144]
2024/09/04 12:53:06 [-] [NEW_REQUEST_ACCEPTED] [unknown] [192.168.0.144]
2024/09/04 12:53:06 [336] [LOCATING_SERVICE] [chrome] [127.0]
2024/09/04 12:53:06 [336] [USING_DOCKER] [chrome] [127.0]
2024/09/04 12:53:06 [336] [CREATING_CONTAINER] [selenoid/chrome:127.0]
2024/09/04 12:53:07 [336] [STARTING_CONTAINER] [selenoid/chrome:127.0] [ac6d632cc57f6f6e8c59a3c29f3784691a33bc7f70dcf9975ecb7aa2d9184b18]
2024/09/04 12:53:07 [336] [CONTAINER_STARTED] [selenoid/chrome:127.0] [ac6d632cc57f6f6e8c59a3c29f3784691a33bc7f70dcf9975ecb7aa2d9184b18] [0.19s]
2024/09/04 12:53:07 [336] [SERVICE_STARTED] [selenoid/chrome:127.0] [ac6d632cc57f6f6e8c59a3c29f3784691a33bc7f70dcf9975ecb7aa2d9184b18] [0.31s]
2024/09/04 12:53:07 [336] [PROXY_TO] [ac6d632cc57f6f6e8c59a3c29f3784691a33bc7f70dcf9975ecb7aa2d9184b18] [http://172.17.0.5:4444/]
2024/09/04 12:53:07 [336] [SESSION_ATTEMPTED] [http://172.17.0.5:4444/] [1]
2024/09/04 12:53:07 [336] [SESSION_CREATED] [b01d05103c20fd08eea5287b37517f30] [1] [0.90s]
2024/09/04 12:53:11 [339] [CONTAINER_LOGS] [ac6d632cc57f6f6e8c59a3c29f3784691a33bc7f70dcf9975ecb7aa2d9184b18]
2024/09/04 12:53:11 [340] [VNC_ENABLED] [b01d05103c20fd08eea5287b37517f30]

Some of selenoid-ui logs:

2024/09/04 12:26:16 [WS_PROXY] [/ws/logs/a3b0dead0b058a37d056f247997aa8b0] [ws://192.168.0.184:4445/logs/a3b0dead0b058a37d056f247997aa8b0]
2024/09/04 12:26:16 [WS_PROXY] [/ws/vnc/a3b0dead0b058a37d056f247997aa8b0] [ws://192.168.0.184:4445/vnc/a3b0dead0b058a37d056f247997aa8b0]
2024/09/04 12:30:32 [WS_PROXY] [/vnc/a3b0dead0b058a37d056f247997aa8b0] [CLOSED]
2024/09/04 12:30:32 [WS_PROXY] [/logs/a3b0dead0b058a37d056f247997aa8b0] [CLOSED]
2024/09/04 12:31:22 [WS_PROXY] [/ws/logs/a12187ec49043c3abe46b15cd624a705] [ws://192.168.0.184:4445/logs/a12187ec49043c3abe46b15cd624a705]
2024/09/04 12:31:22 [WS_PROXY] [/ws/vnc/a12187ec49043c3abe46b15cd624a705] [ws://192.168.0.184:4445/vnc/a12187ec49043c3abe46b15cd624a705]
2024/09/04 12:53:04 Client added. 4 registered clients
2024/09/04 12:53:11 [WS_PROXY] [/ws/logs/b01d05103c20fd08eea5287b37517f30] [ws://192.168.0.184:4445/logs/b01d05103c20fd08eea5287b37517f30]
2024/09/04 12:53:11 [WS_PROXY] [/ws/vnc/b01d05103c20fd08eea5287b37517f30] [ws://192.168.0.184:4445/vnc/b01d05103c20fd08eea5287b37517f30]

chrome container logs:

19
2024/09/04 12:31:19 [INIT] [Listening on :7070]
Waiting X server...
Logging to: /dev/null
Waiting X server...
Starting ChromeDriver 127.0.6533.72 (9755e24ca85aa18ffa16c743f660a3d914902775-refs/branch-heads/6533@{#1760}) on port 4444
All remote connections are allowed. Use an allowlist instead!
Please see https://chromedriver.chromium.org/security-considerations for suggestions on keeping ChromeDriver safe.
ChromeDriver was started successfully.

 --- x11vnc loop: 1 ---

 --- x11vnc loop: waiting for: 175

PORT=5900
2

Sounds like Selenoid needs debuggiing, probably would be best for you to ask the Selenoid community for help on this.

3

From their FAQ

VNC is consuming all my container CPU

On RedHat-based distributions you should set LimitNOFILE=1048576 for containerd.service

1 Like
4

Thanks for the reply, I did, got nothing there. Thanks anyway.

5

Hello, thanks for the reply, just tried this, still nothing, will investigate more that way. Thanks a lot!

6

The FAQ suggestion didn’t make sense to me, but it’s strange they’ve got an entry for this exact issue.

7

Yeah, by their documentation, that should be the solution on red hats, but also got this answer/solution on selenoid github:

this is a known CentOS \ RedHat specific issue related to their kernel \ security settings. Switching to another distribution should fix this.

so I ended up switching to Ubuntu and solved it like that…

8

You could have potentially used the kernel from elrepo and installed kernel-mt or kernel-lt which would give a 6.x kernel and probably resolve the problem as well if the RHEL kernel is crippled slightly. The elrepo one should work. Obviously it’s not official RHEL/Rocky kernel at this point, but that shouldn’t be a major problem.