Build: Server with Ubuntu 18.04 in data center with Ubuntu Mate Desktop interface.
As I understand, any GUI app needs a display in which to function. I connect to the server via x2go to display the ubuntu mate interface.
Once connected, I have a scheduled cron job that launches a terminal, a GUI and some commands.
Everything works perfect as I have previously detected what display I'm using as a user and specify that to launch the terminal and the commands.
Problem: if I'm not connected via x2go client to the server and provide that display, I noticed today that the cron job didn't launch at the specific time (08:50), which was previous to my x2go client connection (09:23); it just launched when I did the x2go client connection from my desktop manually -- my understanding is that it didn't launch because there was not any available display.
I'm not technical enough to get more deep into this problem.
¿Is there anyway in which I can make the cron script function (i.e. that it launchs the terminal and the GUI) without the need of manually getting into my desktop and launching the remote desktop client (x2go)?
My ideas go for having another minimal setup in that data center or another that takes the advantages of being there and have a physical monitor to display constantly connected to the main server OR just manually entering the server via x2go every day.
EDIT: When I disconnect the x2go client session from the server, the launched GUI and etc perfectly maintains, without dissapearing because "I have terminated the session and eliminated the display".
Finally got it working with the great help of one of x2go founders (Oleksandr Shneyder) after understanding how x2go handles the sessions and the X server.
Sessions can suspended/hibernated, disconnected and terminated.
Suspended/hibernated: when "manually" or automatically the x2go server side suspends so that it saves resources.
Disconnected: when you exit the session window and the x2go client in your desktop/laptop.
Terminated: when you log out from the DE environment or issue the x2goterminate-session command in the terminal inside the session.
My x2go app was somehow entering into suspending mode in the server, causing that the display (50 in my case) in which the scheduled cronjob need to be run and launche the GUIs, "was not awaken" until I entered into the session via the
app. In that moment, the cronjob started executing.
To tell x2go server to not hibernate, I needed to change the X2GO_NXOPTIONS in /etc/x2go/x2goagent.options to X2GO_NXOPTIONS="sleep=0"
After this, everything functions perfectly in the server.
Hope it helps others.
Related
Basically I have a linux server, that I can connect to using ssh -i *pvKey* *user#host*.
When I'm connected I can open a java application, like I have. The linux server stays open 24/7 and I believe any application I open does the same. How do I reopen an open application if I close windows powershell.
Let's say I go to bed and close windows Powershell, I believe the java application will stay open during the night, which is what I want. How do I reopen that java program again after connecting to the server, so I can continue sending commands in the java application.
For more specific information: The java application I'm talking about is a minecraft server, which I want to leave on 24/7 (with some restarts obv). I want to be able to reopen the java program of the mc-server that has stayed open, so that I can send more commands and possibly restart the mc-server, without having to log into it in minecraft, stopping it, and reopening it in powershell.
This is the first time I try to work with a linux server and powershell, so please excuse my lack of knowledge.
Your remote shell automatically kills all processes that are running in the shell when you exit the shell.
I would probably use screen for this usecase.
Have a nodejs - socketio application kiosk running windows 7 in kiosk mode(desktop).
Occasionally on boot a handshake doesn't occur between socketio and the client app also running on the same pc. There is a connection but it is immediately dropped. This happens randomly roughly 5% of the time on reboot
The only way I've been able to reliably get the handshake working is to manually reboot the pc.
I can see the nodejs trace showing the lost connection when the error occurs.
I was wondering is there was a way for nodejs to dynamically reboot its host pc (in this case running Windows 7)?
Windows has the shutdown command: How do I shutdown - restart - logoff Windows via a bat file?
You should be able to spawn an process to execute that.
I have a remote machine that runs Ubuntu 14.04. It is powered on, but not logged into. I am writing a web application using Node.js that takes a username and password and logs in to this machine. This application is supposed to run on an Android tablet. I am not going to send further commands through the terminal, so I don't really require the session, but just logging in so that the remote machine starts running some processes.
I'm having trouble on how to start coding this. I'm not sure about what Node module to use, and whether or not to use the SSH protocol.
I've gone through a couple of solutions to related questions on the internet, but they either don't work on Android, or need the remote machine to be running some server already(which is not the case here, as the machine is not logged into).
We have Eclipse setup as our IDE on a central Linux server. Everyone will connect to the server, opens an Eclipse instance, work on it.
Eclipse will be run as a background process, showing the GUI to the user.
What happens is, sometimes people disconnect from the SSH session abruptly(making the laptop to sleep ..etc), without properly closing eclipse, which sometimes leaves the Eclipse process running in the background.
Whenever the user tries to connect next time, they are unaware of the existing Eclipse sessions, and continue starting a new one, while the existing Eclipse processes continue running in the background taking up all the resources.
Question is, can we re-connect to that abandoned Eclipse session somehow? Is it possible to bring up the Eclipse in the same state where user left it?
I looked at GNU screen . However, it can't bring the GUI application back to the user.
This seems to be a problematic setup to me. Why not work on the local computer in the first place? But if you want (or have to) to work on the server, better start the desktop directly on the server via XDMCP, VNC, or Citrix XenAPP (commercial).
EDIT: Just found this article about xmove. I haven't heard about it before, but maybe it works.
I am having some problems with launching firefox from a Linux daemon written in C.
When I launch firefox on the machine itself (via terminal) from the command shell using /usr/bin/firefox it works OK and a firefox browser window lanunches as it should.
However if I try this within my C daemon using system("/usr/bin/firefox"), firefox launches its process in the terminal but the browser window is not opened?
A similar thing happens when I try to do this using remote terminal acces. It's something to do with telling the system to open firefox in window mode rather than trying to open it in terminal mode - but I dont know how to specify this using bash commands?
I am using Lubuntu 11.10 in my Linux System.
Any help is most appreciated.
There's a reason I asked why you're attempting to do what you want. I didn't want to get into great details in my comment.
Firefox on Unix is an X-Window process (most of the Linux/Unix desktops are based upon the X11 protocol which is the heart of X-Window). What X-Window does is separate the display of the program from the process running the program. For example, I am now running Firefox from a Linux box at work, but the Linux box is actually displaying the Firefox browser window at home on my Mac.
In order to do this, I had to:
Run X11 on my Mac. The X11 program creates a default X11 client display called 0.0 which pretty much says the first screen and the first instance of X11 running (computer geeks like counting from zero). The process runs in the background on my Mac. In a certain sense, it's really a server process and not a client because it's waiting on port 6000 for a client X11 process (Firefox) to tell it what to do.
Before I run firefox, I have to tell my Mac's X11 process that I grant the X11 server running Firefox to be able to display on my X11 client process. Otherwise, you can imagine someone spamming another person by continuously popping up Windows on their display. You can use the xhost program to do this.
In order to run Firefox on the Linux box, I have tell the Firefox process what X11 client I'm running it on. I can do this by setting the DISPLAY environment variable to something like "10.0.1.33:0.0". This means the X11 client is running the the machine on IP address 10.0.1.33, and I want you to use the first screen, and the first instance of the X11 client on that screen.
Now, I can run Firefox on my Linux box, and the display will display on my Mac.
The problem you're running into is that there's simply no X11 client when you're starting FireFox as a daemon process. An X11 client is associated with a user and a display of some sort. The display could be a virtual display, but there's got to be an X11 client that's running and is addressable in some way, so the process knows where to display the output.
By the way, you said daemon which has a very, very specific meaning in Unix/Linux. A daemon is a process that runs in the background and usually has a service (and a port) associated with it. For example, there's an FTP daemon called ftpd, the mail server uses the sendmail daemon, ssh has the sshd daemon. Daemons have no display associated with them.
However, it looks like you might be using the word to mean launching Firefox via another process. Is that true? If so, you'll have to make sure that Firefox knows the X11 display to use (there's a command line setting to use to specify the display), and that your X11 client (your login session) has given permission for another process to update your display with the program window.
Can you please explain what you're trying to do in a bit more detail? If you simply want to download a file from a remote http server (which of course is running the http daemon process called httpd), you should use curl or wget which don't require a display and are way simpler to use. If you're trying to do something else, let us know exactly what it is.
Firefox needs to know which display it should open on. When you run it from within a gui, even through a terminal emulator, the DISPLAY environment variable is set to the appropriate value. When you launch from the daemon, try system("/usr/bin/firefox -display=:0").
Make sure that the DISPLAY environment variable is properly set in your daemon to refer to the X server that you want your firefox to use.
If the daemon is run as a different user account than the user account that "owns" the X server that you want to use, you will also need to use xauth(1) to configure the authentication token to grant permission to use the X server.
Often times, it is far easier to use ssh -X to tunnel X and properly configure the xauth(1) tokens in one go than try to manage xauth(1) tokens yourself. Maybe adding ssh -X into your environment would be suitable, maybe not. (I've even used ssh -X root#localhost before when I needed to run an X client as root and didn't want to bother with configuring xauth(1) manually. ssh(1) is just so much easier.)