Synopsis

Old jobs left in Qube are often of little to no use.  While their database entries aren't very detrimental to the operation of Qube, the logs from all of those jobs, when ignored, can balloon in size, sometimes filling the drive(s) on which they reside.

By removing old jobs, you reduce the number of files used by the database, and, more importantly, reduce disk space required to hold logs of jobs that are no longer useful to your production/facility.

We have included a python script called job_cleanup.py that takes, as an argument, the number of days worth of jobs that you would like to keep.  It then removes all of the remaining jobs and their logs.  The idea, then, is that you run this script daily, always keeping, for example, the last 30 days's worth of jobs and deleting the rest.  The script looks at the job's completion time rather than submission or start time, so a job will not be considered for removal until the its most recent completion time is older than the specified number of days.

Requirements

Python 2.x must be installed on the supervisor.  For Windows, we recommend Active State's ActivePython.  OS X should have Python 2.x already installed.  Linux should install Python 2.x from their package manager.

While not required, for better performance, the MySQLdb python module should be available.  Assuming you have pip, running  pip install python-mysql  (or  easy_install python-mysql  if you don't have pip) in a terminal/command prompt should installed install the MySQLdb module for you.  You may need to run as sudo on OS X or Linux when you run pip.

How to use the script

You will find this same information by running "job_cleanup.py -h"

Before you begin: Preparation

Before you set up the scheduled task/cron job, you need to be sure the script will run to completion without errors.  

By default, the script will not delete more than 10% of the jobs in the database.  The first time you run the script, you'll likely need to ignore that check, but you probably do not want to ignore it on a daily basis.

The job_cleanup script also provides a way for you to simulate the process without actually doing anything - a dry run.  This way you can see what's going to happen to see if it's in line with your expectations.

For our example, we want our scheduled task to remove all but the last 30 days worth of jobs, removing all of the old job logs and any orphaned logs (those jobs that have been deleted, but their job logs were left behind).

Preparation, then, should go like this:

1. cd QBDIR/utils

2. Do a dry run:  job_cleanup.py -j -d 30 --removeLogs --removeOrphanedLogs -n
   

   This will probably fail the sanity check.  That's ok.  If it does not fail the sanity step, skip to step 4.  If it does fail the sanity check, continue to step 3.

3. Do a dry run, ignoring the sanity check:  job_cleanup.py -j -d 30 --removeLogs --removeOrphanedLogs -n -I 

   This should print out a long list of jobs that will be removed, each line should say "(dry run)" at the end, letting you know it's not actually doing anything. Only when you're satisfied - in other words, when it's not reporting it will delete jobs you want to keep - with what the dry run returns, proceed to step 4.

4. Now run the script without the -n, this will actually delete files and jobs and is irreversible:  job_cleanup.py -j -d 30 --removeLogs --removeOrphanedLogs -I

Step 4 may take a considerable amount of time.

Creating a scheduled task to clean up old jobs on a Windows supervisor

Use the Windows Task Scheduler wizard.  Go to Start > Control Panel > Administrative Tools > Task Scheduler, then click on "Create Basic Task" and follow through the wizard.

You likely want the scheduled task to run daily, in the middle of the night.  You want it to "Start a program" and the program should be "C:\Program Files\pfx\qube\utils\job_cleanup.py" with additional arguments of "-j -d 30 --removeLogs --removeOrphanedLogs" (without quotes).

Note: These arguments will keep the last 30 days worth of jobs.  If you would like more or less, then adjust the -d argument accordingly.

Creating a scheduled task to clean up old jobs on an OS X supervisor

OS X uses launchctl and launchd to schedule scripts. To set this up, create a .plist file with contents similar to this file, which will run the script once a day at 12:03am:

Then perform these steps in a Mac Terminal (shell):

• The sample script is written to run each day at 3 minutes past midnight. You can change the Hour & Minute tags to suit your installation. You can also restrict this to running, say, weekly on Sunday by adding <key>Weekday</key> <integer>0</integer> into the StartCalendarInterval dictionary.
• Note that the output of stderr and stdout is written to /var/tmp/qb.cleanup.log. This can be changed by you to the location of your choice, and you can separate stderr and stdout into two different files if you prefer.
• Testing this setup first by adding '-n' as an argument in the file is a good idea.

You can test the script without waiting for midnight by typing:

You can remove the script with this commands:

Creating a cron job to clean up old jobs on a Linux supervisor

Add a file in /etc/cron.daily called job_cleanup.  Be sure it is executable by all (chmod a+x job_cleanup).  This is a shell script that will be run daily. A working example looks like this:

Note: These arguments will keep the last 30 days worth of jobs.  If you would like more or less, then adjust the -d argument accordingly.