Cannot detect any display running

[Britgirl]

Inotamira, provided you are using Arch on Xorg and not Wayland, you could submit logs as Mth wrote just above. This topic is specifically related to Arch on Xorg. If you’re using Wayland or another distro, you should open a new topic.

loulou921222,  please submit the logs as requested.

I’d like to add at this point that Arch is not one of the officially supported distros which are Ubuntu, Fedora, Red Hat (and CentOS), Debian, Suse (and OpenSuse). The official list is here: https://www.nomachine.com/AR07H00568. Having an “officially supported list” doesn’t mean we won’t investigate and fix NoMachine-related problems are sometimes brought to our attention on other Linux flavours, such as this one with Arch on Xorg 🙂

As this article states: https://www.nomachine.com/AR11K00740
“Troubleshooting X problems can be complex. Troubleshooting desktop environments can be complex.”

[loulou921222]

Thank you, however the problem is not specific to the login window. If I switch to another TTY (not logging into the account in a X server), and restart the server, I can connect with NoMachine even just on the login screen. It’s only when I startup the system for the first time that for the first hour, NoMachine can’t see the X server running, regardless of if I have logged in or not.

This evening I’ll get back to that machine and try to get a log, I will have to completely restart the computer because restarting the server doesn’t allow me to re-produce the problem, NoMachine works after the server has been restarted just on the login screen.

I’ll try doing nxserver –logrotate, then restarting the machine, and hopefully that’ll collect the necessary logs.

[loulou921222]

I have followed the instructions from “Server on Linux”, then restarted the computer so reproduce the problem, and then created the compressed log files, here they are 🙂

Attachments:

1. NoMachine-log.tar.gz

[loulou921222]

Sorry, I didn’t read it clearly last time, I have sent the logs by email just now.

[Britgirl]

We got the logs thank you and will update the topic soon 🙂

[Britgirl]

We are still not able to reproduce this problem and the logs you submitted were not complete. Either you didn’t enable debug or they are not from the Xubuntu server host. (the quickest way to enable logs: https://www.nomachine.com/DT10O00162)

[loulou921222]

I’ll do it again, here are my exact steps this time:

1. sudo /etc/NX/nxserver –logrotate

2. sudo /etc/NX/nxserver –debug –enable all

3. restart the computer, reproducing the problem

4. sudo /etc/NX/nxserver –debug –collect

5. collecting it from /usr/NX/var/log/archives

[Mth]

Hello.

The logs are good, but a bit puzzling.

We are using installed external program ss to find the Xserver sockets that are running in the system to get which displays are to be made
accessible.

In your case the process “/bin/ss -lnx” returns nothing we can use. This is unusual, especially for Xorg. The process ends without error
so the number of options here are limited.

If you are able to connect to this machine via ssh when it is in the Login Window state, could you run the command:

/bin/ss -lnx

manually and confirm that there are not any failures or errors. If it is the case, we would need an output of three commands when machine is still in login
window:

/bin/ss -lnx
stat /tmp/.X11-unix/*
ps awwxo 'ppid,pid,sid,comm,args'

If there is a problem with sharing the output of ps program, we are only interested in the Xorg processes and their process tree (parents and children).

Please send the output of those commands the same way as previous logs.

/Mth

[loulou921222]

I restarted the machine (to ensure that nothing is different compared to when it first starts up) landing it back on its login screen, then SSHed in. As far as I can observe, /bin/ss -lnx looks normal. Here are /bin/ss -lnx, stat /tmp/.X11-unix/*, and ps awwxo ‘ppid,pid,sid,comm,args’.

Attachments:

1. 

   Screenshot_20201124-175947-scaled.jpg
   

[loulou921222]

It’s worth mentioning that restarting the server while the machine is on the login screen does allow me to then connect.

[loulou921222]

Tomorrow I should be able to do it on another computer and send it in text format like my previous logs

[Mth]

Hello

So this looks fine. There are two possibilities either something is wrong with user ‘nx’ and access to the ‘ss’ command on login window,
or the problem is that nxserver process that runs it is started too early on the system startup and does not fully initialize.

Could you please run the following command like before – via ssh
when system is in login window:

sudo su nx -s /bin/bash -c '/bin/ss -lnx'

and see if there are any problems.

/Mth

[loulou921222]

I’ve done that, I can’t seem to spot anything out of the ordinary. I have also sent the output 🙂

[loulou921222]

I’ve tried adding a few seconds sleep to the service, which makes it so that it doesn’t prompt me when I connect that there is no display running, but rather goes into a loading screen that never ends.

[loulou921222]

I’m guessing that it’s starting too early in the startup process, because when I am on SSH on the login window, if I restart nxserver, I can then connect, even though I’m still only on the login screen, therefore I don’t think it’s because of a problem with the NX user on the login screen, but I may be jumping too quickly to conclusions

[Author]

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