Adding crond and crontab

[ajauberg]

I have successfully built a new firmware using the 2.2.1 SDK, adding a number of Busybox applications that are disabled by default. I am now struggling with understanding the structure of the SDK and were to put things:

1. I want to start the crond daemon at boot time, how do I accomplish this?

2. When I start crond it asks for the catalog /var/spool/cron/crontabs. This catalog is however non-persistent, and must be recreated at every boot. Could I use the /etc/crontabs instead, and how do I accomplish this?

3. There are two busybox folders, named Busybox and Busybox-1.6.1. The latter does not seem to be in use?


Any help greatly appreciated!

[UBNT-keba]

1. Take a look to /usr/etc/rc.d/* scripts. There are some calls to scripts' files that are called from persistent dir if these files exist.

2. Configure crontab daemon to use /etc/persistent/crontabs. /etc/persistent directory is persistent and is saved by cfgmtd -w -p /etc or through the web by apply changes

3. Busybox-1.6.1 is not used yet but it is newer than used one (in directory busybox).

[ajauberg]

2. Configure crontab daemon to use /etc/persistent/crontabs. /etc/persistent directory is persistent and is saved by cfgmtd -w -p /etc or through the web by apply changes

Thanks for the info, but it is not clear to me how I can configure the crontabs daemon. If I place it in the /usr/etc/startup.list there is no room for parameters?

[UBNT-keba]

Hi,

You have to do something like this:
Put your crontab daemon exec line with parameters into /etc/persistent/rc.poststart file. So it will be executed after system boots up. Do not forget to send daemons to background to avoid system boot blocking.

/etc/persistent/rc.poststart sample:

echo "SHELL=/bin/sh" > /etc/crontab
echo "PATH=/sbin:/bin:/usr/sbin:/usr/bin" >> /etc/crontab
echo "# m h dom mon dow user command" >> /etc/crontab
echo "17 * * * * ubnt echo 'DONE SOMETHING'" >> /etc/crontab

/sbin/cron &


Just try. We are not using cron so I don't know what is exact parameters and crontab syntax has to be used.

Good luck

[ajauberg]

This is the code I came down to to make crond running. The following is the contents of the /etc/persistent/rc.poststart file that is called by the framework:

#!/bin/sh

mkdir /var/spool
mkdir /var/spool/cron
mkdir /var/spool/cron/crontabs

echo "*/5 * * * * <add your cron commands here>" >> /var/spool/cron/crontabs/ubnt

crond

[drwho17]

This is the code I came down to to make crond running. The following is the contents of the /etc/persistent/rc.poststart file that is called by the framework:

#!/bin/sh

mkdir /var/spool
mkdir /var/spool/cron
mkdir /var/spool/cron/crontabs

echo "*/5 * * * * <add your cron commands here>" >> /var/spool/cron/crontabs/ubnt

crond

[susanspy]

hello all,


i am susan here, thanksa for informative post, please do some more informative post here.


thanks a lot


cheers!!!!!!!!!!!!!!!!!

[EzioO]

I found a strange cron behaviour on NanoStations M2 running AirOs 5.3.3

1) crond process is running

2) crontab is correctly configured

3) nothing happens

If I do minor changes in crontab (crontab -e) such as adding-removing a meaningless task or change the output redirection and/or restart crond and/or a mix of the two operation, after a few attempts my cron-ed tasks start working.

It looks rather weird to me, is there any "rule" I should follow to make cron work without any tampering, "out-of-the-box"?

Thanks,

Ezio