[SOLVED] Problem with cron and unison

jcerdan · 2008-07-01 18:58:22

I've got a very strange problem I cannot solve.

I have set unison to synchronize my laptop (mercure) against my home computer (jupiter). It works really fine.
I can run it from the terminal:

unison -batch CERTES

and it runs good.

I have set ssh keys so that id doesn't ask me for a password. And that runs fine too because if I do ssh to jupiter, I log in without any password.

That's what the unison profile looks like:

[jordi@mercure ~]$ cat .unison/CERTES.prf 
root = /home/jordi/CERTES
root = ssh://jordi@192.168.7.2//home/jordi/Macbook

After this, everything is ok.

Then I set a cron job so this is done once an hour everyday using crontab -e:

0 * * * * /usr/bin/unison -batch CERTES

And every hour I receive this mail:

Contacting server...
Permission denied, please try again.
Permission denied, please try again.
Permission denied (publickey,password).
Fatal error: Lost connection with the server

Ok then, this seems like cron can't log into jupiter with ssh as I thought. So I modify /etc/ssh/sshd_config to put this option:
PermitUserEnvironment yes

I do the same on mercure, even if I think it's useless, but...

I always receive the same error and I can't get the 2 folders synchronzed.

Before my hard drive crashed a week ago, I had unison running by cron and it was working nice, but now I'm unable to do it again...

Does anyone has a clue about what's happening and how to solve it?

Last edited by jcerdan (2008-07-04 09:52:00)

fukawi2 · 2008-07-02 01:56:04

Sounds like your environment isn't being set properly...

Have you tried putting it in to a bash script, then running the script from cron?

#!/bin/bash
/usr/bin/unison -batch CERTES

jcerdan · 2008-07-02 07:16:38

I have just tried this and it does not work. I receive the same error. Yes I think also that the problem is inssh config, but in the unison FAQ they just talk about PermitUserEnvironment variable set to "yes".

I really don't know how to solve this. Is there a kind of test that would help me discover what's happening?

jcerdan · 2008-07-02 09:54:47

Okay, I tried to run unison under root and I receive the same errors.

So It's clear that crontab is trying to run under root environment and not under the user one. I feel like I am very close to solve this problem!

fukawi2 · 2008-07-03 01:39:13

Leave the script running under your username, and add this line to the script after the #!/bin/bash line:

source /home/YOURUSERNAME/.bash_profile
source /home/YOURUSERNAME/.bashrc

That should ensure your environment is setup properly I hope. Your PATH or some other environment variable probably isn't being set correctly in the non-interactive shell (cron) whereas it does get set correctly in the interactive shell (your login).

If that still doesn't work, can you post the output of the `env` command?

If you put this in your crontab:

env | mail -s "env output" your email@address.com

you will get a list of the environment variables in the non-interactive shell e-mailed to you. Then you can compare that to the output from just typing in manually and seeing what the difference is, and if there's something missing.

jcerdan · 2008-07-03 08:13:20

I have tried adding source to the crontab but I got the same error.

This is the env output from cron:

CONSOLE=/dev/console
SHELL=/bin/sh
CMDLINE=root=/dev/disk/by-uuid/25d2ee78-61ac-4b43-929a-28180b156786 ro
TERM=linux
rootdelay=0
USER=jordi
INIT_VERSION=sysvinit-2.86
ro=y
PATH=/bin:/usr/bin:/sbin:/usr/sbin
_=/usr/bin/env
RUNLEVEL=3
PWD=/home/jordi
PREVLEVEL=N
root=/dev/disk/by-uuid/25d2ee78-61ac-4b43-929a-28180b156786
SHLVL=3
HOME=/home/jordi
kinit_params= rootfstype=ext3 rootdelay=0

And this is the env output from the terminal:

[jordi@mercure ~]$ env
XDG_DATA_HOME=/home/jordi/.local/share
SHELL=/bin/bash
TERM=xterm
DESKTOP_STARTUP_ID=
HISTSIZE=1000
QT_XFT=true
GTK_RC_FILES=/etc/gtk/gtkrc:/home/jordi/.gtkrc-1.2-gnome2
WINDOWID=54526543
QTDIR=/opt/qt
GTK_MODULES=gnomebreakpad
USER=jordi
GNOME_KEYRING_SOCKET=/tmp/keyring-C1rLTl/socket
SSH_AUTH_SOCK=/tmp/keyring-C1rLTl/ssh
KDEDIR=/opt/kde
OOO_FORCE_DESKTOP=gnome
SESSION_MANAGER=local/mercure:/tmp/.ICE-unix/3449
USERNAME=jordi
MOZ_PLUGIN_PATH=/usr/lib/mozilla/plugins:/opt/mozilla/lib/plugins
XDG_CONFIG_DIRS=/etc/xdg:/opt/kde/etc/xdg
PATH=/bin:/usr/bin:/sbin:/usr/sbin:/opt/java/jre/bin:/opt/kde/bin:/usr/bin/perlbin/site:/usr/bin/perlbin/vendor:/usr/bin/perlbin/core:/opt/qt/bin
DESKTOP_SESSION=gnome
GDM_XSERVER_LOCATION=local
INPUTRC=/etc/inputrc
PWD=/home/jordi
JAVA_HOME=/opt/java/jre
LIBXCB_ALLOW_SLOPPY_LOCK=true
EDITOR=vi
LANG=es_ES.utf8
GNOME_KEYRING_PID=3448
GDM_LANG=es_ES.utf8
KDEDIRS=/opt/kde:/usr
PS1=[\u@\h \W]\$ 
PS3=> 
GDMSESSION=gnome
PS2=> 
HISTCONTROL=erasedups
SHLVL=1
HOME=/home/jordi
PS4=+ 
XDG_CONFIG_HOME=/home/jordi/.config
GNOME_DESKTOP_SESSION_ID=Default
XDG_CACHE_HOME=/home/jordi/.cache
LOGNAME=jordi
LESS=-R
CLASSPATH=:/opt/java/jre/lib
DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-5ncgDqnWoO,guid=1e082c45cdb24be2d415016e486c820b
XDG_DATA_DIRS=/usr/share:/usr/local/share:/usr/local/share/:/usr/share/:/usr/share/gdm/:/opt/kde/share
PKG_CONFIG_PATH=:/opt/kde/lib/pkgconfig:/opt/qt/lib/pkgconfig
WINDOWPATH=7
DISPLAY=:0.0
J2REDIR=/opt/java/jre
G_BROKEN_FILENAMES=yes
COLORTERM=gnome-terminal
XAUTHORITY=/home/jordi/.Xauthority
_=/usr/bin/env

A lot of vars are different, but they refer to the Gnome environment. I can see that SHELL, TERM are different, but I don't know what can make the difference.

Do you think there's a problem there?

fukawi2 · 2008-07-03 23:44:19

There's some SSH stuff in there too, which might be stuffing you up, and generally a lot of stuff that it different which looks like is because cron is running your script under /bin/sh whereas when you run it, it's running under /bin/bash

I'm not 100% what the 'correct' way to fix that is. I'd probably try something like this, at least for testing to see if that is the issue:

# mv /bin/sh /bin/sh.ORIGINAL
# ln -s /bin/bash /bin/sh

That will substitute /bash for sh, although I'm not sure if bash will behave differently when called as /bin/sh instead of /bin/bash

(Edit: I'm AFK for the next 7 days, so hopefully someone else can jump in an help you from here)

Last edited by fukawi2 (2008-07-03 23:45:04)

jcerdan · 2008-07-04 09:51:17

I solved it!!! Hurrah!

You (fukawi2) gave me the idea to have a look again to the ssh config. I found that my ssh keys had a passphrase...I really don't remember me setting a passphrase but..
Furthermore, as this passphrase is not asked on ssh terminal (because gnome unblocks the keys repository on login), I wasn't suspecting this!

well, now unison synchronises good!

Thanks a lot for your interest and help Fukawi2.

Jordi.

fukawi2 · 2008-07-12 01:42:03

You're welcome

Arch Linux

#1 2008-07-01 18:58:22

[SOLVED] Problem with cron and unison

#2 2008-07-02 01:56:04

Re: [SOLVED] Problem with cron and unison

#3 2008-07-02 07:16:38

Re: [SOLVED] Problem with cron and unison

#4 2008-07-02 09:54:47

Re: [SOLVED] Problem with cron and unison

#5 2008-07-03 01:39:13

Re: [SOLVED] Problem with cron and unison

#6 2008-07-03 08:13:20

Re: [SOLVED] Problem with cron and unison

#7 2008-07-03 23:44:19

Re: [SOLVED] Problem with cron and unison

#8 2008-07-04 09:51:17

Re: [SOLVED] Problem with cron and unison

#9 2008-07-12 01:42:03

Re: [SOLVED] Problem with cron and unison

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