I have to run NodeJS application which has to run uninterruptedly, but I need to stop it and restart it every 10 minutes.
I'm Working on a dedicated Ubuntu 18.04 machine.
I have read something about cron but I don't know well how it works. Does it stop the command that was run with it?
You can use forever to run the application, and set up a cron job to restart it in forever every five minutes. As a bonus, forever will also restart it for you if it fails in between cron job executions.
In my knowledge, the cron doesn't stop the command that had run before, but you could add the logic to do that check in your application.
Here you can find an article that shows some solutions to prevent duplicate cron job executions.
Related
I have a requirement of running a node script (not app or dapp), which has no front -end files (html, css). This script will send transactions (call smart contract function) in regular intervals. the only constraint is that this script needs to run perpetually (forever) without stopping, unless a specific command is given by admin. Please do suggest how we could achieve this? Thanks.
PS: in case you have a better platform suggestion other than heroku, those are welcome as well with details. Tx.
Unix cron works fine for this kind of things. Just add a cron in your crontab with command :
crontab -e
Then just set your pattern and add a line with your command to launch, for example this will run each day at 3.00 AM:
0 3 * * * /root/backup.sh
Then don't forget to reload your cron process:
sudo service cron restart
Define your pattern here : https://crontab.guru/
You can have a look at kue.
The good thing about kue is, that it gives you a UI where an admin can view the running, failed, jobs etc. Also, you can configure it to stop a job programmatically.
I have node server that I want to restart whenever it stopped. For this case I setup system cron on ubuntu server to execute a simple bash script that will track node server every minute and log the server status. Now this cron trigger this bash script and logs relevant status every minute but node server doesn't execute(Using simple linux command I can check if node server running or not). When manually running that bash script node server starts but something happening when cron executes that script. I am trying to fix this meanwhile any help will be appreciated.
Thanks
instead of doing this with cron i think you have to use spervisor in order to keep the process running check this supervisor website
So I am relatively new to Centos, version 6.2. I have a service that needs to be mnonitored as a cron job, and if it stops needs to be restarted. I have a few ideas on how to monitor it, but when it comes to getting it restarted thats when I get stuck. I also know the PiD of the service I want to monitor.
You can use supervise for this: http://cr.yp.to/daemontools/supervise.html
Put it in your crontab to launch on system start:
#reboot supervise foo
I'm trying to run quick php update over cron tab on Cloud9 IDE.
Here is my crontab -l:
*/2 * * * * php /home/ubuntu/workspace/public_html/updater.php
I also tried to use data from "whereis php" instead of simple php, but still nothing.
And here comes my question. Is there any time restriction eg. 1 hour minimum for cron in C9?
Or maybe I'm doing something wrong.
Tried to restart cron already.
Cron daemon is not started. You have to start it manually. Your output from px -aef | grep cron shows that grep is running not cron.
sudo cron start
Please read here, from the C9 FAQ:
We currently do not support cron jobs within Cloud9 workspaces. The way to proceed would be to get a Cloud9 premium plan which allows you to create SSH workspaces
You may need to run the cron daemon to make the cron job run ("service cron start"). However Cloud9 workspaces are paused when they are inactive so it will only run when you're actively logged into the IDE.
I've been setting up my server recently and today I had to restart it... then I realised all of my Node apps I had running weren't running anymore. I'm using Node Forever module to keep the apps running, but then I realised I still need to have them starting when my server restarts or shut downs and powers up again.
I have been researching the best way to do this, but what I'm trying just doesn't seem to work. I've created an Upstart script in my /etc/init/ folder on my Ubuntu Server 10.04LTS remote server and tried restarting and it doesn't seem to do anything. Nothing is getting listed when I run forever list.
Here is my current Upstart script I was trying out today:
#/etc/init/myapp.conf
start on (local-filesystems and net-device-up IFACE=eth0)
stop on shutdown
script
exec sudo /usr/local/bin/node /var/www/myapp/myapp.forever.js
end script
I use Forever in a Node script as I find it easier to configure it how I want. It's confirmed that the script runs just fine if I do this outside the script, there is just something wrong with the Upstart script itself. It seems to have the same permissions as all the other Upstart scripts in /etc/init/ folder.
As an additional note, I have gone through almost all the answers I could find here on StackOverflow, and that it how I got together the script that I have at present.
UPDATE:
With Tom's answer, I have now tried:
#/etc/init/myapp.conf
start on (local-filesystems and net-device-up IFACE=eth0)
stop on shutdown
exec sudo /usr/local/bin/node /var/www/myapp/myapp.forever.js
But it's still not working.
So I don't know why this isn't running when I restart my server. Please help!
This is not a very happy setup. The way upstart works is that it starts your process running it using the process id for the start command. Forever JS works similarly, it is probably inspired by Upstart.
When you try to run forever.js with upstart, the forever process you create in your upstart script exits immediately after starting. Upstart counts on having the process continue to run.
When I tried to run forever using upstart, I wound up with five different forever process running because upstart thought it had failed to start forever, and it retried five times.
Did you try doing it without the start script lines?
description "my server"
author "name"
start on (local-filesystems and net-device-up IFACE=eth0)
stop on shutdown
#respawn if you were not using forever
exec sudo /usr/local/bin/node myapp.forever.js
Source: http://caolanmcmahon.com/posts/deploying_node_js_with_upstart
I've opted to use an #reboot statement in the user's crontab file, which will execute forever on server restarts.
#reboot forever start app.js
Additional Reading - http://www.cyberciti.biz/faq/linux-execute-cron-job-after-system-reboot/