For some testing, I need to reboot my system every minute. I have a busybox based system, installed cron using opkg. I setup a cron job using crontab, everything  looks ok:root@SL1000-1103DC:~# crontab -l# DO NOT EDIT THIS FILE - edit the master and reinstall.# (/tmp/crontab.1962 installed on Tue Jun 16 14:57:01 2015)# (Cron version -- $Id: crontab.c,v 2.13 1994/01/17 03:20:37 vixie Exp $)* * * * * /sbin/rebootroot@SL1000-1103DC:~# But the command is never run after the system boots? However, if I restart cron, then everything works:root@SL1000-1103DC:~# /etc/init.d/cron restartStopping Vixie-cron.Starting Vixie-cron.root@SL1000-1103DC:~# dateTue Jun 16 14:58:18 EDT 2015root@SL1000-1103DC:~# Broadcast message from root (Tue Jun 16 14:59:00 2015):The system is going down for reboot NOW!INIT: Switching to runlevel: 6So is there something different about running cron at startup, versus running from a command line? Maybe some subtle permissions issue? All of this is done at root level. Hmmm....Edit: More info - looks like the unit is rebooting at odd times, as if cron was confused about the time? I left it alone, and it rebooted several times. Last time I had tail on /var/log/messages, and I see a message from cron issuing the command. So now the question is - why is cron confused about the time?
Cron not working at startup, but works if restarted?
cron;startup;busybox
Sounds like cron was started before the time synchronization had settled, so the fix is to sync the time before cron starts.