I am not convinced that is the right terminology but here is my situation.
I log into an Ubuntu server using ssh and start a node app that I wrote. I would like for the app to continue rinning even when I close the ssh window or when the window times out. I 'think' there is a way to do this by writing a .conf file for the app and placing it in /etc but I dont know where to go to learn how to do that.
Any tips?
You can use the program nohup to accomplish this. It is most likely already installed on your Ubuntu distribution, it was on my 12.04 install.
nohup node test.js &
This command kicks off node test.js. Output will be streamed to nohup.out so you can view what is has been doing later on if you so like. Even after the ssh session is ended, the process will keep right on going.
To kill the process later on, you can do a "killall node" or you can manually grep for the PID and kill it that way using "ps -ef | grep node"
Linux: Prevent a background process from being stopped after closing SSH client
Related
I am on arch linux, accessing an account on a server over SSH. I have run a bash script containing recursion that results in an infinite loop of "no such file or directory" which continues despite any interrupt command ctrl C etc, it is totally uninterruptible. This eventually results in an endless stream of bash: fork: No child processes. I cannot execute any commands whilst this happens, and when it stops with "Resource temporarily unavailable", i am unable to execute any commands to kill the script because "bash: fork: No child processes" starts up again. I have no idea what to do, any help?
ps doesn't work
Looks like you've caused a fork bomb. You can try the methods here to stop it, but you'll most likely end up needing to reboot.
Run kill -9 -1 from the user login that caused the forkbomb . No need to reboot.
PS: Consult your seniors before running it on Prod server
1) ps faux (find PID and place in second command)
2) kill [PID]
If any virus attack then again this process come so you need to enable virus scanner on cpanel and scan and remove.
Important:
Hosting providers must install the following services for this interface to appear:
The ClamAV Scanner plugin in WHM’s Manage Plugins interface (WHM >> Home >> cPanel >> Manage Plugins).
The Exim Mail Server service on the server in WHM’s Service Manager interface (WHM >> Home >> Service Configuration >> Service Manager).
Run ps faux (you might need to run it from other user or with sudo) and search for the offending process (may look like a big branch of the tree)
If needed, kill the process via its PID
Well, I'm basically trying to make a bash script runs a node script forever. I made the following bash script:
#!/bin/bash
while true ; do
cd /myscope/
unlink nohup.out
node myscript.js
sleep 6
done & echo $! > pid
I'm expecting that when it runs, it starts up node with the given script, checks if node exits, sleeps for 6 seconds if so and reopen node. Also, I'm expecting it to run in background and writes it's pid (the bash pid) on a file called "pid".
Everything explained above works as expected, apparently, but I'm also expecting that when the pid of the bash script is killed, the node script would stop running, I don't know why that made sense in my mind, but when it comes to practice, it doesn't work. The bash script is killed indeed, but the node script keeps running and that is freaking me out.
I've tested it in the terminal, by not sending the bash script to the background and entering ctrl+c, both scripts gets killed.
I'm obviously miss understanding something on the way the background process works. For god sake, can anybody help me?
There are lots of tools that let you do what you're trying, just two off the top of my head:
https://github.com/nodejitsu/forever - A simple CLI tool for ensuring that a given script runs continuously (i.e. forever)
https://github.com/remy/nodemon - Monitor for any changes in your node.js application and automatically restart the server - perfect for development
Maybe the second it's not what you're looking for, but still worth a look.
If you can't or don't want to use those then the problem is that if you kill the parent process the child one is still there, so, you should kill that too:
pkill -TERM -P $PID
where $PID is the parent PID.
I'm connecting to my ubuntu server using ssh. I start an encoding program using a command. However, it seems that when my ssh session closes (because I started it on a laptop which went to sleep). Is there a way to avoid this (of course preventing my laptop from sleeping is not a permanent solution).
Run your command with nohup or use screen
nohup is better when your program generate some loging output because it's forward to file and then you can check it, but with screen you can detach ssh session and when you log again you can restore your work-space. For encoding I'll use nohup. It is easier and you probably run it in background, so you really don't need detaching
Screen is the best for you.
screen -S some_name
than run it. Detach it with: ctrl+a d
Next time, attach it with:
screen -rd some_name
You can have more runnning screens. To show the list of them:
screen -ls
Install "screen" on your ubuntu server, that way you can start any program in your session, disconnect the output of the program from your current session and exit.
Later when you connect again to your server, you can restore the program which will continue running and see its progress.
Somehow this isn't yielded by a google search.
I'm scripting a server in node.js. I start the server by executing its script with the node program:
node myserver.js
But the server staying up is dependent on my ssh session. How can I make this (and all such processes) persistent? Init.d?
Use the nohup command:
From http://en.wikipedia.org/wiki/Nohup
nohup is a POSIX command to ignore the HUP (hangup) signal, enabling the command to keep running after the user who issues the command has logged out. The HUP (hangup) signal is by convention the way a terminal warns depending processes of logout.
Try this:
nohup node myserver.js &
Have you tried GNU screen? Using it, a process can continue to run when you end your ssh session. nohup is a standard *nix command that will allow you to do the same, albeit in a more limited way.
Use screen. Type screen from the terminal and then launch your process. If you disconnect you can reconnect to the ssh session, by typing 'screen -ls' (to see active screens) and 'screen -r' to reconnect.
The program needs to run in a daemonized mode. Here's a good post for doing this in Ubuntu.
nohup is good to run the job under. If the job is already running, you can try disown -h (at least in bash)
I have a PHP script with infinite loop. I need this script running forever. So, I run
php /path/to/script.php > /dev/null &
And it works in background in my current user's security context. But when I close terminal window (log off), of course, CentOS Linux kills my program.
I see two guesses: run from a different user in background or make a daemon. I need help in each situation.
Thanks a lot!
nohup is your friend.
nohup command &
I think the general solution to that is nohup:
nohup is a POSIX command to ignore the HUP (hangup) signal, enabling the command to keep running after the user who issues the command has logged out. The HUP (hangup) signal is by convention the way a terminal warns depending processes of logout.
nohup is most often used to run commands in the background as daemons. Output that would normally go to the terminal goes to a file called nohup.out if it has not already been redirected. This command is very helpful when there is a need to run numerous batch jobs which are inter-dependent.
nohup is your friend.
You could:
Install screen and run the command from there. screen is a persistent terminal session that you can leave running.
Write an init/upstart (whatever you use) script so it loads on boot
Use the pear lib system_daemon
Use cron if batch work fits the scenario better (just remember to check for running instances before you launch another, iff concurrency is an issue)
Edit: or as everybody else and their brother has just said, nohup
Using command
nohup your_command &
For example
nohup phantomjs highcharts-convert.js -host 127.0.0.1 -port 3003 &
here "phantomjs highcharts-convert.js -host 127.0.0.1 -port 3003" was my command