When executing service cron status, you may find such errors:
Failed to connect to socket /var/run/dbus/system_bus_socket: No such file or directory
The solution is to install dbus for messaging between systems:
1、sudoapt-getinstalldbus
2. Start dbus: sudo /etc/init.d/dbus start, ubantu will prompt to use service dbus start to start, so use
service dbus start to start it.
Then run service cron start and service cron status to execute correctly.