Crontab not working
March 3, 2024, 20:19
Hi, I have never worked with cronjobs before and I need a little help.
I have a Pi 5 that hosts a small website using a python script. Now I want the Pi to reboot every day at 5 AM and automatically start the server.
I searched for ways to do that and I came around crontab
According to a guide I created a new job
sudo crontab -e
I added the following lines:
@reboot root sleep 60 && sudo python /mnt/ssd/server.py > ~/logs/server.log 2>&1
0 5 root sudo reboot
I added the sleep to make sure the ssd with the server on it is mounted by the time the job is executed
However after rebooting nothing happened.
So for debugging I added:
root echo &date >> ~/logs/minute.log
This should write the current time and date to a minute.log file
But after waiting for a couple of minutes still nothing happened
I have no idea what I missed and why it is not working.
Does anyone have suggestions what I can try to make it work?
When you edit crontab and add sudo before crontab it is roots crontab you are changing.
So change crontab to
0 5 * reboot
And I would advice you create a bash file with @reboot root sleep 60 && sudo python /mnt/ssd/server.py > ~/logs/server.log 2>&1 and I also suspect that sudo is making the life harder for you.
ok, I've tried that
now I have the following lines
0 5 reboot
@reboot sleep 60 && python /mnt/ssd/server.py > ~/logs/server.log 2>&1
echo &date >> ~/logs/minute.log
but that also doesn't do anything
Oh it could be your environment variables, the bash shell that crontab uses has NO env variables!
so reboot should be /usr/sbin/reboot
And the echo &date use just /usr/bin/date >> /home/<user>/logs/minute.log
And I dont think ~ works,use absolute paths
Now I have this
@reboot /usr/bin/sleep 60 && /usr/bin/python /mnt/ssd/server.py > /home/daedalus/logs/server.log 2>&1
0 5 /usr/sbin/reboot
/usr/bin/date >> home/daedalus/logs/minute.log
You have missed a / before home
All right the minute.log works now
I'll thy the reboot now
Nice to see that you know how to troubleshoot, you simplified the problem and thats makes it easier to isolate the issue
thanks
YW
Did it work?
Kind of. The command did run but I got a No such file or directory error
now I'm working on that
the server.py was not found
The mount happen after crontab run ? Then you should look into how to make a systemd unit file of server.py
Ok, but I'm new to Linux and I don't know what systemd unit files are
I've got it working now. I just had a typo in the path to server.py
Nice
And systemd is the service that starts other services in the background. And in the unit file you can describe dependencies, example if you want a web server it should have a dependency "network" because what use do a web server have without a wworking network.
Check:
https://www.shubhamdipt.com/blog/how-to-create-a-systemd-service-in-linux/ and https://linuxhandbook.com/create-systemd-services/ if you are interested to learn more
cool, thanks