I'm running a Django (v3.1.7) application on a headless remote Ubuntu (v20.04.3) that I'm looking to have start at reboot using crontab. The script below runs all ok from the command line. I've been through here crontabs-reboot-only-works-for-root and the linked suggestions as well but still haven't identified the issue. I've added logging (see *.log below) but do not get any helpful output.
EDIT: The test screen works both from the command line and at reboot. The django and streaming screens do not work at reboot. Checking python executable with which python3 returns /usr/bin/python3. So it looks to me that I have the correct permissions for reboot.sh and cron should be able to find python3 as it is in PATH= in the crontab file.
/home/myapp/reboot.sh
#!/bin/bash
echo "$(date) Starting reboot.sh"
start_django () {
echo "$(date) Entering start_django"
screen -S django -dm bash -c 'cd /home/myapp && /usr/local/bin/gunicorn myapp.wsgi:application --bind 0.0.0.0:8000' > /home/myapp/django_cron.log 2>&1
sleep 1
echo "$(date) Exiting start_django"
}
start_stream () {
echo "$(date) Entering start_stream"
screen -S streaming -dm bash -c 'cd /home/myapp/data_api && python3 api_stream_client.py' > /home/myapp/stream_cron.log 2>&1
sleep 1
echo "$(date) Exiting start_stream"
}
start_test () {
echo "$(date) Entering start_test"
screen -S testa -dm bash -c 'cd /home/myapp && exec bash' > /home/myapp/test_cron.log 2>&1
sleep 1
echo "$(date) Exiting start_test"
}
if screen -list | grep -q "No Sockets found"; then
echo "$(date) No screens available"
echo "$(date) Starting test"
start_test
echo "$(date) Starting django"
start_django
echo "$(date) Starting stream"
start_stream
else
if screen -list | grep -q "django"; then
echo "$(date) django exists"
else
echo "$(date) django does not exist - starting now"
start_django
fi
if screen -list | grep -q "streaming"; then
echo "$(date) stream exists"
else
echo "$(date) stream does not exist - starting now"
start_stream
fi
if screen -list | grep -q "test"; then
echo "$(date) test exists"
else
echo "$(date) test does not exist - starting now"
start_test
fi
fi
contab -l
# m h dom mon dow command
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
@reboot sleep 60 && /home/myapp/reboot.sh > /home/myapp/cron.log 2>&1
/var/log/cron.log
Jan 28 15:21:44 localhost systemd-timesyncd[637]: Network configuration changed, trying to establish connection.
Jan 28 15:21:44 localhost cron[814]: (CRON) INFO (pidfile fd = 3)
Jan 28 15:21:44 localhost cron[814]: (CRON) INFO (Running @reboot jobs)
Jan 28 15:21:44 localhost CRON[824]: (root) CMD (sleep 60 && /home/financialdashboard/reboot.sh > /home/financialdashboard/cron.log 2>&1)
Jan 28 15:21:46 localhost systemd-timesyncd[637]: Network configuration changed, trying to establish connection.
Jan 28 15:21:50 localhost systemd-timesyncd[637]: Network configuration changed, trying to establish connection.
Jan 28 15:21:55 localhost systemd-timesyncd[637]: Network configuration changed, trying to establish connection.
Jan 28 15:21:55 localhost systemd-timesyncd[637]: Initial synchronization to time server [2001:67c:1560:8003::c7]:123 (ntp.ubuntu.com).
/home/myapp/cron.log
Fri Jan 28 15:22:44 UTC 2022 Starting reboot.sh
Fri Jan 28 15:22:44 UTC 2022 No screens available
Fri Jan 28 15:22:44 UTC 2022 Starting test
Fri Jan 28 15:22:44 UTC 2022 Entering start_test
Fri Jan 28 15:22:45 UTC 2022 Exiting start_test
Fri Jan 28 15:22:45 UTC 2022 Starting django
Fri Jan 28 15:22:45 UTC 2022 Entering start_django
Fri Jan 28 15:22:46 UTC 2022 Exiting start_django
Fri Jan 28 15:22:46 UTC 2022 Starting stream
Fri Jan 28 15:22:46 UTC 2022 Entering start_stream
Fri Jan 28 15:22:47 UTC 2022 Exiting start_stream
django_cron.log, stream_cron.log and test_cron.log are all empty
Fixed: The django and streaming screens where relying on some environment variables which are not loaded with cron. See here where-can-i-set-environment-variables-that-crontab-will-use for more details.
I was able to get logging working for the screens by following this gnu-screen-logtstamp-string and this save-screen-program-output-to-a-file .
My updated /home/myapp/reboot.sh:
#!/bin/bash
SHELL=/bin/bash
echo "$(date) Starting reboot.sh"
# Load environment variables
source /etc/profile.d/env.sh
start_django () {
echo "$(date) Entering start_django"
screen -c /home/myapp/django_cron_log.conf -L -S django -dm bash -c 'cd /home/myapp && /usr/local/bin/gunicorn myapp.wsgi:application --bind 0.0.0.0:8000'
echo "$(date) Exiting start_django"
}
start_stream () {
echo "$(date) Entering start_stream"
screen -c /home/myapp/stream_cron_log.conf -L -S streaming -dm bash -c 'cd /home/myapp/data_api && python3 api_stream_client.py && exec bash'
echo "$(date) Exiting start_stream"
}
if screen -list | grep -q "No Sockets found"; then
echo "$(date) No screens available"
echo "$(date) Starting django"
start_django
echo "$(date) Starting stream"
start_stream
else
if screen -list | grep -q "django"; then
echo "$(date) django exists; not starting django"
else
echo "$(date) django does not exist - starting now"
start_django
fi
if screen -list | grep -q "streaming"; then
echo "$(date) stream exists; not starting stream"
else
echo "$(date) stream does not exist - starting now"
start_stream
fi
fi
The -c /home/myapp/*_cron_log.conf -L in screen will be removed for production.