I have program that I need to run at startup in the background, so far I have it in rc.local like so:
sudo ./simple_program &
However this does not take into consideration if the program crashes. I need it so that whenever the program crashes, it is restarted again.
I think the approach is to write a bash script and run that instead in rc.local, where the bash script calls the simple_program and reruns it if needed. However, I'm not quite sure exactly what to do here. Could someone provide me a template?
Try with monit or daemontools, they are specifically designed to supervise other processes
Related
Before explaining what my problem is, please know that I have looked up for solutions on similar topics but none of them seems to work nor even to corresponds to my problem.
What I am trying to do:
I have this python code on multiple files that I run with flask with the following command:
python -m flask run --host=0.0.0.0
So far, everything works, but I would like this code to automatically run everytime the computer boots. In the future this will be used on mini PCs without any graphical interface nor human intervention.
Since I need to do some configuration checks before running the web server, I've created a powershell script that ends with Flask running (using the previous command).
So far, everything works too. Now we're coming to the problem:
I'd like this script to run when I boot the machine. Specificity: Every things needs to work with Administrator privileges, on the local system without any interaction.
I've tried scheduled tasks but Flask won't run even if the rest of the script works (like creating folders or other things)
Ok, it's not a big deal I have other ways to do it, so I've created a Windows Service in C# to run the Script at startup on the local system.
The script works, I've checked the privileges too, everything's fine but arriving at the flask command line that is supposed to make it run, nothing works.
It's the same thing if I run flask using "pythonw" which is supposed to run python as a background process.
What the problem seems to be:
Well, as long as I run flask and I have either a command prompt or a powershell terminal, everything works greats. But if in a way or another I run the script as a background process, it won't work.
Normally it would take around 30 seconds for Flask to start-up. Here if I try to create a folder right after flask ended starting up (as a test) I can see the folder is created almost instantly, which means the process is immediately killed.
The problem doesn't seem to come from the service itself but really Windows that kills the process I don't know why
I'm running out of idea so if you guys have anything that I could try it would really help me.
I've been finding recently that my KDB launch script is crashing. I need to restart my computer and then it will run fine. I launch KDB from a CMD prompt and I can't figure out where to look to see what process is running in the background which is causing it to crash. Does anybody know what I should check?
Thanks.
Trying running a blank kdb instance with just:
set QHOME=C:\q
set PATH=%PATH%;c:\q\w32
and then
q -p 1234
(doesn't need to be in a batch script, you should be able to just run those commands in a cmd prompt). If kdb comes up then kdb isn't the problem.
Then try to manually load the startup script to see if the problem is there:
q)system"l C:\\q\\ServerFiles\\server.q"
If this works fine then the problem isn't there. The last place it can be is in the database/directory load, so load that:
q)system"l c:\\q\\files"
If none of these cause an error then something else is affecting your kdb instance, either something running on a timer (check .z.ts) or something is connecting externally
So I did finally discover what the issue was. I had a few instances of KDB that would run via Task Scheduler in the evening and then close. One of the instances wouldn't end and so it was continually running. This would cause KDB to crash since there was already an instance running. The restart would stop the process so it could be run again. I deleted the task scheduler event and recreated it and now the event runs KDB and closes the way it is supposed to. Thanks for all of the help in trying to figure this out!
I am creating a Perl script that creates a Net::WebSocket::Server on port 3000. Now I had the (not so brilliant) idea to start the script in the browser via CGI, so it runs in the background and can't be stopped. However, I have to restart the script whenever I modify it.
Is it possible to stop a CGI script in an endless loop, except by restarting the computer?
You didn't say what operating system you are on, so we cannot give you specific advice on how to find and kill the process. But you can always restart the web server application. CGI scripts are children of the server process (probably an Apache) that starts them. If you simply restart the Apache server, they should all be terminated.
Please don't put code that is supposed to run persistently in your cgi-bin directory. That's a bad idea, as you discovered.
When I deployed my play application I built the package using:
dist
This created a file that I can run on my server like:
sudo ./bin/app-name -Dhttp.port=9090
This works fine for testing but how can I run this process in the background?
I will eventually have to use upstart or some sort of process monitoring tool to make sure this process is running after server reboots etc.
Using play 2.3.x
Since you are on ubuntu
sudo ./bin/app-name -Dhttp.port=9090 &
should do the trick.
Ceating the upstart script is also fairly easy https://askubuntu.com/questions/18802/how-to-correctly-add-a-custom-daemon-to-init-d
In your case it would be in /etc/init/app-name.conf and look like
# app-name
#
start on stopped rc RUNLEVEL=[2345]
stop on runlevel [!2345]
respawn
exec $PATH_TO_APP/bin/app-name -Dhttp.port=9090
Of course you will want to change the RUNLEVEL and the PATH_TO_APP
That of course depends on the system at which you're deploying the app, anyway in general you need to run it as a deamon.
Refer to your system's documentations, I'm pretty sure that you will find tutorial very soon.
I'm working with an embedded computer that has a Debian on it. I already manage to run a command just before it has booted and play the "bell" to tell that is ready to work, and for example try to connect to a service.
The problem is that I need to play the bell (or run any command/program) when the system is halted so is safe to un-plug the power. Is there any runscript that run just after halt?
If you have a look in /etc/init.d, you'll see a script called halt. I'm pretty certain that when /sbin/halt is called in a runlevel other than 0 or 6, it calls /sbin/shutdown, which runs this script (unless called with an -n flag). So maybe you could add your own hook into that script? Obviously, it would be before the final halt was called, but nothing runs after that, so maybe that's ok.
Another option would be to use the fact that all running processes get sent a SIGTERM followed (a second or so later) by a SIGKILL. So you could write a simple daemon that just sat there until given a SIGTERM, at which point it went "ping" and died.