i am trying to run a cron job which will execute my shell script, my shell script is having hive & pig scripts. I am setting the cron job to execute after every 2 mins but before my shell script is getting finish my cron job starts again is it going to effect my result or once the script finishes its execution then only it will start. I am in a bit of dilemma here. Please help.
Thanks
I think there are two ways to better resolve this, a long way and a short way:
Long way (probably most correct):
Use something like Luigi to manage job dependencies, then run that with Cron (it won't run more than one of the same job).
Luigi will handle all your job dependencies for you and you can make sure that a particular job only executes once. It's a little more work to get set-up, but it's really worth it.
Short Way:
Lock files have already been mentioned, but you can do this on HDFS too, that way it doesn't depend on where you run the cron job from.
Instead of checking for a lock file, put a flag on HDFS when you start and finish the job, and have this as a standard thing in all of your cron jobs:
# at start
hadoop fs -touchz /jobs/job1/2016-07-01/_STARTED
# at finish
hadoop fs -touchz /jobs/job1/2016-07-01/_COMPLETED
# Then check them (pseudocode):
if(!started && !completed): run_job; add_completed; remove_started
At the start of the script, have a check:
#!/bin/bash
if [ -e /tmp/file.lock ]; then
rm /tmp/file.lock # removes the lock and continue
else
exit # No lock file exists, which means prev execution has not completed.
fi
.... # Your script here
touch /tmp/file.lock
There are many others ways of achieving the same. I am giving a simple example.
Related
Im working with the LSF, running bsub commands.
I'm implementing the -Ep switch to run a post exec script. This works great until the Job is killed or hits a memory limit, run limit etc.
Is there any way for the job to detect its running out of resource and then run the script? or to force it to run the script even if its been killed?
I guess my other option is running job with a dependency on that job which will run the "post exec" script when it finishes.
Any thoughts?
Kind Regards,
TheBigPeeler
From the documentation, you should be seeing the behaviour that you want.
A post-execution command runs after the job finishes, regardless of
the exit state of the job. Once a post-execution command is associated
with a job, that command runs even if the job fails. You cannot
configure the post-execution command to run only under certain
conditions.
I thought that maybe the interaction with JOB_INCLUDE_POSTEXEC (lsb.params) could account for the difference, but from my test the post-exec still runs in both cases. I used runlimit (bsub -W) to trigger the job kill.
Is it possible that the post exec is running, but exits early?
What version of LSF are you using? (What's the output of mbatchd -V and sbatchd -V)
I'm running a shell scripts that executes several tasks. The thing is that the script does not wait for a task to end before starting the next one. My script should work differently, waiting for one task to be completed before the next one to start. Is there a way to do that? My script looks like this
sbatch retr.sc 19860101 19860630
scp EN/EN1986* myhostname#myhost.it:/storage/myhostname/MetFiles
the first command runs retr.sc, that retrieves files and it takes half an hour roughly. The second command, though, is run right soon, moving just some files to destination. I wish the scp command to be run only when the first is complete.
thanks in advance
You have several options:
use srun rather than sbatch: srun retr.sc 19860101 19860630
use sbatch for the second command as well, and make it depend on the first one
like this:
RES=$(sbatch retr.sc 19860101 19860630)
sbatch --depend=after:${RES##* } --wrap "scp EN/EN1986* myhostname#myhost.it:/storage/myhostname/MetFiles"
create one script that incorporates both retr.sc and scp and submit that script.
sbatch exits immediately on submitting the job to slurm.
salloc will wait for the job to finish before exiting.
from the man page:
$ salloc -N16 xterm
salloc: Granted job allocation 65537
(at this point the xterm appears, and salloc waits for xterm to exit)
salloc: Relinquishing job allocation 65537
Thanks for you replies
I've sorted out this way
RES=$(sbatch retr.sc $date1 $date2)
array=(${RES// / })
JOBID=${array[3]}
year1={date1:0:4}
sbatch --dependency=afterok:${JOBID} scp.sh $year1
where scp.sh is the script for transferring the file to my local machine
I am on shared hosting and I'm trying to schedule cronjob to run every now and then. Via cPanel I scheduled to execute my script but even though that according to my host support the cronjob runs, the script doesn't seem as doing anything. The cron job command I set via cPanel is:
/bin/sh /home1/myusername/public_html/somefolder/cronjob2.sh
and the cronjob2.sh
#!/bin/bash
/home1/myusername/public_html/somefolder/node_modules/forever/bin/forever stop 0
when via SSH I execute:
/home1/myusername/public_html/somefolder/cronjob2.sh
it stops forever process as needed. From cronjob doesn't do anything.
How can I get this working?
EDIT:
So I've tried:
/bin/sh /home1/username/public_html/somefolder/cronjob2.sh >> /tmp/mylog 2>&1
and mylog entries say:
/usr/bin/env: node: No such file or directory
It seems that forever needs to run node and this cannot be found. How would I possibly fix this?
EDIT2:
Accepted answer at superuser.com. Thank you all for help
https://superuser.com/questions/763261/simple-script-run-via-cronjob-doesnt-work-but-works-from-shell/763288#763288
For cron job lines in a crontab it's not required to specify kind of shell or e.g. of perl.
It's enough, that your script contains
shebang
line.
Therefore you should remove /bin/sh from your cron job line.
Another aspect, that might cause a different behavior of your script by interactive start and by cron daemon start is possible different environment, first of all the PATH variable. Therefore check, if you script is able to be executed in very restricted environment, that is provided by cron daemon. You can determine your cron job environment experimentally by start of temporary cron job, that executes "env" command and writes its output to a file.
Once more aspect: Have you redirected STDOUT and STDERR of the cron job to a log file and read its content to analyze the issue? You can do it as follows:
your_cron_job >/tmp/any_name.log 2>&1
According to what you wrote, when you run your script via SSH, you are using bash, because this line is the first of your script:
#!/bin/bash
However, in the crontab, you are forcing the use of sh instead of bash. Are you sure your script is fully compatible with sh? Otherwise, simply replace /bin/sh with /bin/bash in your cron command and test again.
I have a question.
I want to run more instance of same job in parallel from within a script: I have a loop in which I invoke jobs with dsjob and without option "-wait" and "-jobstatus".
I want that jobs completed before script termination, but I don't know how to verify if job instance terminated.
I though to use wait command but it is not appropriate.
Thanks in advance
First,you should assure job compile option "Allow Multiple Instance" choose.
Second:
#!/bin/bash
. /home/dsadm/.bash_profile
INVOCATION=(1 2 3 4 5)
cd $DSHOME/bin
for id in ${INVOCATION[#]}
do
./dsjob -run -mode NORMAL -wait test demo.$id
done
project -- test
job -- demo
$id -- invocation id
the two line in shell scipt:guarantee the environment path can work.
Run the jobs like you say without the -wait, and then loop around running dsjob -jobinfo and parse the output for a job status of 1 or 2. When all jobs return this status, they are all finished.
You might find, though, that you check the status of the job before it actually starts running and you might pick up an old status. You might be able to fix this by first resetting the job instance and waiting for a status of "Not running", prior to running the job.
Invoke the jobs in loop without wait or job-status option
after your loop , check the jobs status by dsjob command
Example - dsjob -jobinfo projectname jobname.invocationid
you can code one more loop for this also and use sleep command under that
write yours further logic as per status of the jobs
but its good to create Job Sequence to invoke this multi-instance job simultaneously with the help of different invoaction-ids
create a sequence job if these are in same process
create different sequences or directly create different scripts to trigger these jobs simultaneously with invocation- ids and schedule in same time.
Best option create a standard generalized script where each thing will be getting created or getting value as per input command line parameters
Example - log files on the basis of jobname + invocation-id
then schedule the same script for different parameters or invocations .
am new to hadoop and a small help is required.
Suppose if i ran the job in background using shell scripting, how do i know whether the job is completed or not. The reason am asking is, once the job is completed my script has to move output file to some other location. How can i check whether job completed or outfile exists or not using hdfs.
Thanks
MRK
You need to be careful in the way you are detecting the job is done in this way, because there might be output before your job is completely finished.
To answer your direct question, to test for existence I typically do hadoop fs -ls $output | wc -l and then make sure the number is greater than 0.
My suggestion is you use && to tack on the move:
hadoop ... myjob.jar ... && hadoop fs -mv $output $new_output &
This will complete the job, and then perform the move afterwards.
You can use JobConf.setJobEndNotificationURI() to get notified when the job gets completed.
I think you can also check for the pid of the process that started the Hadoop job using the ps command.