Using Crontab on OMV - updated

GBano · 19. September 2021

Hello,

This might be a borderline OMV issue since it is also linked to a programme I'm using.

Parts of my OMV storage should be used as CCTV loop storage.

So I'm using FFMPEG to capture the stream and direct / store it in segments on an OMV partition and created a crontab entry for it.

FFMPEG has a bug in that it seems to ignore the -t / -timelimit option, so I wanted to kill and re-start the process periodically- via another crontab entry preceeding the re-start.

However, the only way I can kill the process (tested manyally) is by using the process ID.

Code

killall ffmpeg

does not work (nor does kill ffmpeg).

Since the proces ID is dynamic, this won't work- unless there is another way to kill a process via crontab.

Why would it not take the process name but only the ID?

GBano · 19. September 2021

Update:

Code

killall 15 ffmpeg

did the trick to stop ffmpeg.

I've now placed both commands (start & kill) in the crontab and am testing it.

Perhaps one can re-start it with killall 1 , it remains to be seen.

GBano · 20. September 2021

Another update:

Logged in as a user (not root),

crontab -e

edited the crontab:

Code

00 10 20 9 * USER ffmpeg -loglevel debug -hide_banner -i 'http://videostreamIP' -y -f segment -segment_time 3600 -segment_format mp4 segment_wrap 3 -c copy /srv/path/to/file-%03d.mp4 
00 11 20 9 * USER killall 15 ffmpeg

CTRL-X, save

...and wait: Nothing.

If I execute both commands manually in the terminal, everything works.

So the commands seem correct.

But cron doesn't seem to work.

Did I miss something here? Need to logon as root? Wrong crontab?

gderf · 20. September 2021

Try using the fully qualified path to ffmpeg

NAS-i-Goreng · 2. Oktober 2021

This might sound daft....

'/usr/bin/ffmpeg' ? That's where I'd locate ffmpg.

But I tried and it doesn't work.

Here's another thing: Shouldn't 'crontab -e ' also show the existing cron job that I added via the GUI which does a backup from HDD1 to HDD2 and which is active and working?

Can't see it anywhere there.

But yes, I created this one as 'admin', so may be on admin/root level.

macom · 2. Oktober 2021

Zitat von NAS-i-Goreng

Here's another thing: Shouldn't 'crontab -e ' also show the existing cron job that I added via the GUI which does a backup from HDD1 to HDD2 and which is active and working?

OMV does not use crontab. The jobs created in the GUI are executed via /etc/cron.d/openmediavault-rsync.

The actual jobs are in /var/lib/openmediavault/cron.d/

gderf · 2. Oktober 2021

Zitat von NAS-i-Goreng

This might sound daft....
'/usr/bin/ffmpeg' ? That's where I'd locate ffmpg.
But I tried and it doesn't work.

Are you guessing where that file is or did you actually run find, locate, or which to get its path. Also, ffmepg is not in the OMV default install.

NAS-i-Goreng · 2. Oktober 2021

Since executable binaries can be found in (usr)/bin I just searched this subdirectory and found ffmpeg.

Yes, it was not part of the OEM setup, so I installed it.

I can run the ffmpeg command manually from a user level. This made me assume it would work on the same level as a user-level cron job.

NAS-i-Goreng · 3. Oktober 2021

Update:

I ran a very simple test command on this user-level 'crontab -e':

cp /path/to/source/file.txt /path/to/destination/

And it did nothing.

My conclusion: It's not the way the command is called up.

Must be something else...

Using Crontab on OMV - updated

GBano 20. September 2021

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