Package: cron Version: 3.0pl1-130 Apparently the users' @reboot cron jobs might be run before the system init scripts have been completed. Sample (using sysv init):
# ls -al /etc/rc2.d/ total 20 drwxr-xr-x 2 root root 4096 Jan 2 14:44 . drwxr-xr-x 153 root root 12288 Jan 2 14:44 .. lrwxrwxrwx 1 root root 29 Mar 29 2016 K01apache-htcacheclean -> ../init.d/apache-htcacheclean -rw-r--r-- 1 root root 677 Dec 27 10:49 README lrwxrwxrwx 1 root root 26 Jan 2 06:51 S01console-setup.sh -> ../init.d/console-setup.sh lrwxrwxrwx 1 root root 22 Jan 2 06:51 S02acpi-fakekey -> ../init.d/acpi-fakekey lrwxrwxrwx 1 root root 16 Jan 2 06:51 S02dhcpcd -> ../init.d/dhcpcd lrwxrwxrwx 1 root root 22 Jan 2 06:51 S02lvm2-lvmetad -> ../init.d/lvm2-lvmetad lrwxrwxrwx 1 root root 23 Jan 2 06:51 S02lvm2-lvmpolld -> ../init.d/lvm2-lvmpolld lrwxrwxrwx 1 root root 18 Jan 2 06:51 S02minidlna -> ../init.d/minidlna lrwxrwxrwx 1 root root 14 Jan 2 06:51 S02motd -> ../init.d/motd lrwxrwxrwx 1 root root 17 Jan 2 06:51 S02rsyslog -> ../init.d/rsyslog lrwxrwxrwx 1 root root 14 Jan 2 06:51 S02sudo -> ../init.d/sudo lrwxrwxrwx 1 root root 15 Jan 2 06:51 S02uuidd -> ../init.d/uuidd lrwxrwxrwx 1 root root 19 Jan 2 06:51 S02zfs-mount -> ../init.d/zfs-mount lrwxrwxrwx 1 root root 22 Jan 2 06:52 S03acpi-support -> ../init.d/acpi-support lrwxrwxrwx 1 root root 15 Jan 2 06:52 S03acpid -> ../init.d/acpid lrwxrwxrwx 1 root root 17 Jan 2 06:52 S03anacron -> ../init.d/anacron lrwxrwxrwx 1 root root 13 Jan 2 06:52 S03atd -> ../init.d/atd lrwxrwxrwx 1 root root 16 Jan 2 06:52 S03autofs -> ../init.d/autofs lrwxrwxrwx 1 root root 23 Jan 2 06:52 S03clamav-daemon -> ../init.d/clamav-daemon lrwxrwxrwx 1 root root 14 Jan 2 06:52 S03dbus -> ../init.d/dbus lrwxrwxrwx 1 root root 17 Jan 2 06:52 S03dnsmasq -> ../init.d/dnsmasq lrwxrwxrwx 1 root root 20 Jan 2 06:52 S03git-daemon -> ../init.d/git-daemon lrwxrwxrwx 1 root root 21 Jan 2 06:52 S03loadcpufreq -> ../init.d/loadcpufreq lrwxrwxrwx 1 root root 14 Jan 2 06:52 S03nscd -> ../init.d/nscd lrwxrwxrwx 1 root root 13 Jan 2 06:52 S03ntp -> ../init.d/ntp lrwxrwxrwx 1 root root 19 Jan 2 06:52 S03opensmtpd -> ../init.d/opensmtpd lrwxrwxrwx 1 root root 19 Jan 2 06:52 S03rmnologin -> ../init.d/rmnologin lrwxrwxrwx 1 root root 23 Jan 2 06:52 S03smartmontools -> ../init.d/smartmontools lrwxrwxrwx 1 root root 22 Jan 2 06:52 S03spamassassin -> ../init.d/spamassassin lrwxrwxrwx 1 root root 13 Jan 2 06:52 S03ssh -> ../init.d/ssh lrwxrwxrwx 1 root root 17 Jan 2 06:52 S04apache2 -> ../init.d/apache2 lrwxrwxrwx 1 root root 23 Jan 2 06:52 S05apt-cacher-ng -> ../init.d/apt-cacher-ng lrwxrwxrwx 1 root root 22 Jan 2 06:51 S05avahi-daemon -> ../init.d/avahi-daemon lrwxrwxrwx 1 root root 18 Jan 2 06:52 S05bootlogs -> ../init.d/bootlogs lrwxrwxrwx 1 root root 26 Jan 2 06:51 S05clamav-freshclam -> ../init.d/clamav-freshclam lrwxrwxrwx 1 root root 23 Jan 2 06:51 S05clamav-milter -> ../init.d/clamav-milter lrwxrwxrwx 1 root root 22 Jan 2 06:51 S05cpufrequtils -> ../init.d/cpufrequtils lrwxrwxrwx 1 root root 14 Jan 2 06:51 S05cron -> ../init.d/cron lrwxrwxrwx 1 root root 25 Jan 2 06:52 S05milter-greylist -> ../init.d/milter-greylist lrwxrwxrwx 1 root root 15 Jan 2 14:44 S05mysql -> ../init.d/mysql lrwxrwxrwx 1 root root 27 Jan 2 06:53 S05nfs-kernel-server -> ../init.d/nfs-kernel-server lrwxrwxrwx 1 root root 15 Jan 2 06:51 S05rsync -> ../init.d/rsync lrwxrwxrwx 1 root root 17 Jan 2 14:44 S06dovecot -> ../init.d/dovecot lrwxrwxrwx 1 root root 18 Jan 2 06:51 S07rc.local -> ../init.d/rc.local See how cron and mysql are on the same level? Its easy to imagine that another system service "abc" relying upon mariadb is started *after* mariadb. If the user's @reboot job tries to access abc, then there is a race condition. To make sure that databases and other system services are run before the @reboot cron jobs, you would have to add a ton of new dependencies to cron's init script, and you could still not be sure about it. Or you could specify that cron is started last at boot time, as version 3.0pl1-129 did. See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=767016#20 systemd has the same problem, AFAICT. Regards Harri
