CRON problem: (rsync: Failed to exec ssh: Permission denied (13))

Fairys · 01-07-2008, 08:58 AM

Hi all,

Recently I created a script to rsync two servers. Script uses ssh to make it a bit secure and works fine when executed manually from prompt.
Nothing spectacular in there:

Code:

rsync -e "ssh -i $SSHKEY" $SOURCESRV/$SOURCEDIR $DESTDIR/$DESTDIR

(I asume that I do not have to convince you guys that vars are correct? ;-) )
as stated, this work good when I run it manualy from prompt.
But it does not works when executed from cron. What is wrong with this script? What did I forgot, of what I am NOT aware of?
As I use Webmin to administer my server, lazy ass I am, I know, when I run this job there manualy I get:

Code:

Output from command /some_correct_path/rsync.sh ..
rsync: Failed to exec ssh: Permission denied (13)
rsync error: error in IPC code (code 14) at pipe.c(86) [receiver=2.6.9]
rsync: writefd_unbuffered failed to write 4 bytes [receiver]: Broken pipe (32)
rsync error: error in IPC code (code 14) at io.c(1122) [receiver=2.6.9]

Is there anyone who could assist on this? All help is more then welcome :-)

cheerz and tnx in advance.

MensaWater · 01-07-2008, 02:17 PM

Jobs in cron don't have the same environment variables that ones you run from the command line do. This is because it isn't really "logged in" so runs a minimally configured environment.

The most common cause of problems is PATH. If your script doesn't know where "rsync" and "ssh" are it can't execute them. Try specifying full path to each of these commands in the script or setting them up as variables that have the full pathname so you just use the variable in the command line.

e.g.
export SSH=/usr/bin/ssh
export RSYNC=/usr/bin/rsync
$RSYNC -e "$SSH -i $SSHKEY" $SOURCESRV/$SOURCEDIR $DESTDIR/$DESTDIR

Fairys · 01-08-2008, 03:11 AM

Thank you jlightner for replay.
I heard about that PATH issue so I even 'improved' my script to print PATH so I can see whats there.

Code:

/sbin:/usr/sbin:/bin:/usr/bin:/bin:/usr/bin:/sbin:/usr/sbin:/usr/local/bin:/bin:/usr/bin:/sbin:/usr/sbin:/usr/local/bin

looks good for me.
Anyways I followed your advice and did tried two things:
1.

Code:

RSYNC=/usr/bin/rsync
SSH=/usr/bin/ssh

2.

Code:

export RSYNC=/usr/bin/rsync
export SSH=/usr/bin/ssh

in both solutions I used your line:

Code:

$RSYNC -e "$SSH -i $SSHKEY" $SOURCESRV/$SOURCEDIR $DESTDIR/$DESTDIR

but I still get the same error...

Do you have any other ideas?
cheerz,

MensaWater · 01-08-2008, 09:35 AM

Is the cron job being run as the same user you run from at command line. (i.e. is it the root user when you're running from command line and is this in root's crontab?) ssh trusts are typically done per user.

Also you might want to add an echo line to verify all your variables are what you think they are in the script. Perhaps one of them isn't being set the way you think it is? (SOURCESRV, SOURCEDIR etc...)

griffey · 01-08-2008, 02:07 PM

This may be making things redundant, and I'll be the first to admit I don't know exactly what is and isn't allowed to be listed as a cron event, but what if you created a text file, added the line of your command to it, made that file executable (a "script," even though it's a one-liner) and then called THAT from cron?

That is, make a text file, perhaps called "rsyncjob" with just this in it:
rsync -e "ssh -i $SSHKEY" $SOURCESRV/$SOURCEDIR $DESTDIR/$DESTDIR

Then "chmod +x rsyncjob."

Then in your crontab instead of the big drawn-out command, simply do:

15 12 * * 1-5 /home/path/to/rsyncjob

Again, if that's making things redundant and I am just showing my cron/script naivete, forgive me, but that's probably what I would try if I were faced with a similar situation.

Good luck.

Edited: Part of the reason I think this way is that I run rsnapshot, which is basically an rsync wrapper, and the script I have cron run also includes writing the date out to a log file, then running rsnapshot, then writing to the log file that it has finished, if that makes any sense...

G.--

Fairys · 01-14-2008, 02:36 AM

Hi all,

First of all I would like to thank you for all advice.
Even all sugestions I see here are more or less familiar for me it looks like it is still something else that I overlooked.
Last aproach sugested by griffey is mine preferd aproach to solve a problem: minimize as possible to locate problem faster. jlightner says what I was kinda aware of and I totaly follow his path, I still not there...
Other problem I have with testing it, that it is a cron job so it runs now and then. and bigest problem is that it works manualy... ;-) So I will try to do some other tricks and see whats it wil lrusult in. I will keep you informed guys

cheerz!

chrism01 · 01-16-2008, 06:34 PM

You can temporarily set it in cron to run 'soon', then comment it out in crontab whilst you analyse the results eg if it's now 10:23, set crontab

30 10 * * * mytest.sh >/home/me/mytest.out 2>&1

let it run, then comment it out.
At the 2nd line of the shell file, use
set -xv
which will display all vars as they are used and their translations.
As mentioned, which user it runs as is also significant.