CronJob not running

Question

I have set up a cronjob for root user in ubuntu environment as follows by typing crontab -e   34 11       sh  srv www live CronJobs daily sh   0 08     2 sh  srv www live CronJobs weekly sh   0 08 1     sh  srv www live CronJobs monthly sh  But the cronjob does not run  I have tried checking if the cronjob is running using pgrep cron and that gives process id 3033  The shell script calls a python file and is used to send an email  Running the python file is ok  There s no error in it but the cron doesn t run  The daily sh file has the following code in it  python  srv www live CronJobs daily py python  srv www live CronJobs notification email py python  srv www live CronJobs log kpi py

User · Answer

Another reason crontab will fail  Special handling of the   character   From the man file   The entire command portion of the line  up to a newline or a     character  will be executed by  bin sh or by the shell specified in the SHELL variable of the cronfile   A     character in the command  unless escaped with a backslash      will be changed into newline characters  and all data after the first   will be sent to the command as standard input    In my particular case  I was using date --date  7 days ago     Y- m- d  to produce parameters to my script  and it was failing silently   I finally found out what was going on when I checked syslog and saw my command was truncated at the   symbol   You need to escape it like this   date --date  7 days ago      Y-  m-  d    See here for more details   http   www ducea com 2008 11 12 using-the-character-in-crontab-entries

User · Answer

WTF   My cronjob doesn t run   Here s a checklist guide to debug not running cronjobs   Is the Cron daemon running    Run ps ax   grep cron and look for cron  Debian  service cron start or service cron restart   Is cron working               bin echo  quot cron works quot   gt  gt   tmp file Syntax correct  See below  You obviously need to have write access to the file you are redirecting the output to  A unique file name in  tmp which does not currently exist should always be writable  Probably also add 2 gt  amp 1 to include standard error as well as standard output  or separately output standard error to another file with 2 gt  gt  tmp errors   Is the command working standalone    Check if the script has an error  by doing a dry run on the CLI When testing your command  test as the user whose crontab you are editing  which might not be your login or root   Can cron run your job    Check  var log cron log or  var log messages for errors  Ubuntu  grep CRON  var log syslog Redhat   var log cron   Check permissions   Set executable flag on the command  chmod  x  var www app cron do-stuff php If you redirect the output of your command to a file  verify you have permission to write to that file directory   Check paths   check she-bangs   hashbangs line do not rely on environment variables like PATH  as their value will likely not be the same under cron as under an interactive session   Don t suppress output while debugging   Commonly used is this suppression  30 1       command  gt   dev null 2 gt  amp 1 Re-enable the standard output or standard error message output by removing  gt  dev null 2 gt  amp 1 altogether  or perhaps redirect to a file in a location where you have write access   gt  gt cron out 2 gt  amp 1 will append standard output and standard error to cron out in the invoking user s home directory  If you are trying to figure out why something failed  the error messages will be visible in this file  Read it and understand it   Still not working  Yikes   Raise the cron debug level   Debian  in  etc default cron set EXTRA OPTS  quot -L 2 quot  service cron restart tail -f  var log syslog to see the scripts executed   Ubuntu  in  etc rsyslog d 50-default conf add or comment out line cron crit  var log cron log reload logger sudo  etc init d rsyslog reload re-run cron open  var log cron log  and look for detailed error output   Reminder  deactivate log level  when you are done with debugging   Run cron and check log files again  Cronjob Syntax   Minute  Hour  Day of Month      Month         Day of Week    User Command        0-59   0-23     1-31      1-12 or Jan-Dec   0-6 or Sun-Sat                  0       2                                                 root  usr bin find  This syntax is only correct for the root user  Regular user crontab syntax doesn t have the User field  regular users aren t allowed to run code as any other user     Minute  Hour  Day of Month      Month         Day of Week    Command        0-59   0-23     1-31      1-12 or Jan-Dec   0-6 or Sun-Sat                  0       2                                                  usr bin find  Crontab Commands  crontab -l  Lists all the user s cron tasks    crontab -e  for a specific user  crontab -e -u agentsmith  Starts edit session of your crontab file  When you exit the editor  the modified crontab is installed automatically    crontab -r  Removes your crontab entry from the cron spooler  but not from crontab file

User · Answer

Sometimes the command that cron needs to run is in a directory where cron has no access  typically on systems where users  home directories  permissions are 700 and the command is in that directory

User · Answer

It might also be a timezone problem  Cron uses the local time  Run the command timedatectl to see the machine time and make sure that your crontab is in this same timezone   https   askubuntu com a 536489 1043751

User · Answer

I want to add 2 points that I learned    Cron config files put in  etc cron d  should not contain a dot      Otherwise  it won t be read by cron  If the user running your command is not in  etc shadow  It won t be allowed to schedule cron    Refs    http   manpages ubuntu com manpages xenial en man8 cron 8 html https   help ubuntu com community CronHowto

User · Answer

I ve found another reason for user s crontab not running  the hostname is not present on the hosts file   user ubuntu    cat  etc hostname ubuntu   Now the hosts file   user ubuntu    cat  etc hosts 127 0 0 1 localhost    The following lines are desirable for IPv6 capable hosts   1 ip6-localhost ip6-loopback fe00  0 ip6-localnet ff00  0 ip6-mcastprefix ff02  1 ip6-allnodes ff02  2 ip6-allrouters ff02  3 ip6-allhosts   This is on a Ubuntu 14 04 3 LTS  the way to fix it is adding the hostname to the hosts file so it resembles something like this   user ubuntu    cat  etc hosts 127 0 0 1 ubuntu localhost    The following lines are desirable for IPv6 capable hosts   1 ip6-localhost ip6-loopback fe00  0 ip6-localnet ff00  0 ip6-mcastprefix ff02  1 ip6-allnodes ff02  2 ip6-allrouters ff02  3 ip6-allhosts

User · Answer

For me  the solution was that the file cron was trying to run was in an encrypted directory  more specifcically a user diretory on  home   Although the crontab was configured as root  because the script being run exisited in an encrypted user directory in  home  cron could only read this directory when the user was actually logged in  To see if the directory is encrypted check if this directory exists    home  ecryptfs  lt yourusername gt    if so then you have an encrypted home directory    The fix for me was to move the script in to a non encrypted directory and everythig worked fine

User · Answer

I found useful debugging information on an Ubuntu 16 04 server by running  systemctl status cron service In my case I was kindly informed I had left a comment     off of a remark line  Aug 18 19 12 01 is-feb19 cron 14307   Error  bad minute  while reading  etc crontab Aug 18 19 12 01 is-feb19 cron 14307     system   ERROR  Syntax error  this crontab file will be ignored

User · Answer

To add another point  a file in  etc cron d must contain an empty new line at the end  This is likely related to the response by Luciano which specifies that  The entire command portion of the line  up to a newline or a  quot   quot  character  will be executed

User · Answer

Finally I found the solution  Following is the solution -   Never use relative path in python scripts to be executed via crontab  I did something like this instead -  import os import sys import time  datetime  CLASS PATH     srv www live mainapp classes  SETTINGS PATH     srv www live foodtrade  sys path insert 0  CLASS PATH  sys path insert 1 SETTINGS PATH   import other py files  Never supress the crontab code instead use mailserver and check the mail for the user  That gives clearer insights of what is going

User · Answer

I experienced same problem where crons are not running   We fixed by changing permissions and owner by Crons made root owner as we had mentioned in crontab AND Cronjobs 644 permission given

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