I've got a Pi running Raspberry Pi OS Bookworm. I've been starting a
NODE app (not mine - one that I've downloaded) from a cron job and using
one of the start-at-boot mechanisms (I forget which!).

This has worked until did a "sudo apt update" and "sudo apt upgrade".

Now the cron job fails to start the app, even though an explicit
background job works from a terminal window.

The script that is run from the crob job is

#start
cd /srv/ext/NAS/tplink-energy-monitor

# At midnight, output a double-row separator; otherwise a single-row
separator
date | grep " 00:00"
if [ $? -eq 0 ]; then
echo "====================" >> /srv/ext/NAS/tplink-energy-monitor/tp.log else
echo "--------------------" >> /srv/ext/NAS/tplink-energy-monitor/tp.log
fi

date >> /srv/ext/NAS/tplink-energy-monitor/tp.log

echo "before 'npm start'" >> /srv/ext/NAS/tplink-energy-monitor/tp.log
ps -alef | grep -e node -e npm | grep -v grep | grep -v fusermount >> /srv/ext/NAS/tplink-energy-monitor/tp.log

npm start &

echo "after 'npm start'" >> /srv/ext/NAS/tplink-energy-monitor/tp.log
ps -alef | grep -e node -e npm | grep -v grep | grep -v fusermount >> /srv/ext/NAS/tplink-energy-monitor/tp.log

sleep 30

echo "after 'sleep 30'" >> /srv/ext/NAS/tplink-energy-monitor/tp.log
date >> /srv/ext/NAS/tplink-energy-monitor/tp.log
ps -alef | grep -e node -e npm | grep -v grep | grep -v fusermount >> /srv/ext/NAS/tplink-energy-monitor/tp.log
#end

The critical lines are

cd /srv/ext/NAS/tplink-energy-monitor
npm start &

The rest is logging to check that it works OK.


The script runs fine - all the logging stuff is OK. But it seems that
"node" does not like running as a background job any more when invoked
from a cron job as opposed to a terminal session.

The reason it's run from a cron job is that it has a habit of crashing
every so often (no idea why, and writer of the app doesn't reply to
emails) so I run it from cron every 5 minutes to restart it if it has
stopped.

--- PyGate Linux v1.5.19
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

NY <me@privacy.net> writes:

I've got a Pi running Raspberry Pi OS Bookworm. I've been starting a
NODE app (not mine - one that I've downloaded) from a cron job and
using one of the start-at-boot mechanisms (I forget which!).

This has worked until did a "sudo apt update" and "sudo apt upgrade".

Now the cron job fails to start the app, even though an explicit
background job works from a terminal window.

What is the output from the cron job?

--
https://www.greenend.org.uk/rjk/

--- PyGate Linux v1.5.19
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On Thu, 12 Nov 2026 13:34:27 +0000, NY wrote:

The script runs fine - all the logging stuff is OK. But it seems
that "node" does not like running as a background job any more when
invoked from a cron job as opposed to a terminal session.

What exactly is the error?

The reason it's run from a cron job is that it has a habit of
crashing every so often (no idea why, and writer of the app doesn't
reply to emails) so I run it from cron every 5 minutes to restart it
if it has stopped.

I would do this via a systemd service definition. That provides
automatic monitoring and restarting if/when it crashes (up to some
reasonable limit, to guard against endless loops). And any error
messages should appear in the journal as well.

--- PyGate Linux v1.5.19
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)