rsync and cron #1

[ijeffsc]

This seems like a popular topic, cron and rsync does .

<editorial> I’m really liking nas4free so far in that I doubt I could have set up the basics of ZFS so quickly without. All that time saved though is being burned by tasks that would be pretty routine in a normal server config. Let’s see if I can make a contribution </editorial>

Synopsis: So is issue #1 a bug and should I submit it? There is a 2nd issue but it was a layer 8 problem for your reading enjoyment.

First Cron:

The cron setup is pretty intuitive iff you know cron. Cron has always been subject to careful environment setup and I’ve usually handled that with scripts and/or absolute path names to executables. What is not intuitive (to me) is the behaviour of the “run now” GUI command and exactly what shell is running the script. As an example here is a simple touchme script:

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#!/usr/local/bin/bash

MYFILE=/tmp/mytouchmefile

rm $MYFILE
echo $SHELL > $MYFILE
# /usr/bin/touch $MYFILE
exit

When run from the command line it produces this result:

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[ijeff@nas4free ~/bin]$ ./touchme
[ijeff@nas4free ~/bin]$ ls -l /tmp/mytouchmefile ; cat /tmp/mytouchmefile 
-rw-r--r--  1 ijeff  wheel  10 Dec  6 09:48 /tmp/mytouchmefile
/bin/bash

When run from cron it produces this result:

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[ijeff@nas4free ~/bin]$ ls -l /tmp/mytouchmefile ; cat /tmp/mytouchmefile 
-rw-r--r--  1 ijeff  wheel  8 Dec  6 09:49 /tmp/mytouchmefile
/bin/sh

When run from the “run now” in the GUI it produces this:

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[ijeff@nas4free ~/bin]$ ls -l /tmp/mytouchmefile ; cat /tmp/mytouchmefile 
-rw-r--r--  1 root  wheel  10 Dec  6 09:52 /tmp/mytouchmefile
/bin/tcsh

There is a serious issue here in that the “run now” basically breaks (stops from running) the subsequent runs and has to be cleaned up before the regular cron run can function. These issues were documented in bug #97 although the permissions portion of the problem was not. There was not enough info given in #97 IMHO to reproduce the problem either.

There are two apparent problems.

#1 the file ownership is incorrect in the “run now” cron GUI case
#2 the shell is wrong in the cron case (it should be bash shouldn’t it?)

A bit more debugging and I realize that the second issue isn’t. I should have been looking a bit deeper into the SHELL variable which is the default shell. The new script is:

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#!/usr/local/bin/bash

MYFILE=/tmp/mytouchmefile
rm $MYFILE

ps -l >> $MYFILE
# /usr/bin/touch $MYFILE
exit

This results in cron out put of this (and clearly bash is running (is there a better way to do this?)):

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[ijeff@nas4free ~/bin]$ ls -l /tmp/mytouchmefile ; cat /tmp/mytouchmefile 
-rw-r--r--  1 ijeff  wheel  223 Dec  6 10:43 /tmp/mytouchmefile
 UID   PID  PPID CPU PRI NI   VSZ  RSS MWCHAN STAT TT     TIME COMMAND
1001 11120 11119   0  20  0 17640 3556 ttyin  Is+   0  0:00.29 -bash (bash)
1001 11587 11586   0  20  0 17640 3532 wait   Is    1  0:00.02 -bash (bash)

On the command line I see this:

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[ijeff@nas4free ~/bin]$ ./touchme
[ijeff@nas4free ~/bin]$ ls -l /tmp/mytouchmefile ; cat /tmp/mytouchmefile 
-rw-r--r--  1 ijeff  wheel  385 Dec  6 10:43 /tmp/mytouchmefile
 UID   PID  PPID CPU PRI NI   VSZ  RSS MWCHAN STAT TT     TIME COMMAND
1001 11120 11119   0  20  0 17640 3556 wait   Ss    0  0:00.30 -bash (bash)
1001 12148 11120   0  23  0 17640 3256 wait   S+    0  0:00.01 /usr/local/bin/bash ./touchme
1001 12150 12148   0  23  0 18760 2372 -      R+    0  0:00.00 ps -l
1001 11587 11586   0  20  0 17640 3532 wait   Is    1  0:00.02 -bash (bash)

The cron job is thus in config.xml:

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                <job>
                        <enable/>
                        <uuid>f8eab5f1-9f3d-427d-8329-60054e4ef462</uuid>
                        <desc>touchme</desc>
                        <minute/>
                        <hour/>
                        <day/>
                        <month/>
                        <weekday/>
                        <all_mins>1</all_mins>
                        <all_hours>1</all_hours>
                        <all_days>1</all_days>
                        <all_months>1</all_months>
                        <all_weekdays>1</all_weekdays>
                        <who>ijeff</who>
                        <command>/mnt/Pool1b/DS2Z/home/ijeff/bin/touchme</command>
                </job>

[daoyama]

Thank you for your inspection.

#1 the file ownership is incorrect in the “run now” cron GUI case
#2 the shell is wrong in the cron case (it should be bash shouldn’t it?)

It looks #2 is not a problem. /bin/sh should use shebang in your script.
ps display the process under terminal. But cron is not terminal of course.
(You need ps -U user or ps -a instead.)

#1 is a problem. It should use the user specified by Who field.

[ijeffsc]

Would anyone care to submit this as a bug?

[ijeffsc]

submitted as bug #283.

[zoon01]

Thanks for bug report, please check pm

[ijeffsc]

Corrected in 10.3 thanks to dev team.