Submitting a more complex sequential batch job

Often you may wish to perform some preliminary manipulations on your data files before passing them on to your application for execution, and after that's done, you may wish to do some clean-up work, perhaps making sure that various scratch files have been removed, etc.

The way to do that is to use the second approach presented in the previous section, i.e., to submit a shell script to LoadLeveler.

Below is an example of a job like that. This job comprises three steps:

1.

Obtain information about LoadLeveler variables and write them on a data file. The information is obtained by running env and grep and the data file is constructed by running awk. The data file is written in the form of an Emacs Lisp program.

2.

Invoke the application on the data file, which has been generated dynamically in the previous step. The application, in this case, is emacs, and the data file is the Emacs Lisp program saved on llenv.el.

3.

Cleanup, i.e., remove the data file generated in step 1, since it is no longer needed.

Of course, there are simpler ways to list LoadLeveler environmental variables, but this toy example neatly illustrates the idea of a three step procedure:

1.

data preprocessing/generation

2.

data manipulation by the main application

3.

data cleanup

Most simple LoadLeveler jobs have this structure.

gustav@sp20:../LoadLeveler 23:23:59 !735 $ cat env.ll
# @ shell = /afs/ovpit.indiana.edu/@sys/gnu/bin/bash
# @ output = env.out
# @ error = env.err
# @ job_type = serial
# @ class = test
# @ notification = always
# @ environment = COPY_ALL
# @ queue
env | grep LOADL | \
awk ' BEGIN { 
         { printf "(defun llenv ()\n" } 
         { printf "   (princ \"LoadLeveler variables:\\n\") " }
      }
      { printf "   (princ \"\t%s\\n\")\n", $0 } 
      END { print ")"} ' > llenv.el
emacs -batch -l llenv.el -f llenv > llenv.out
rm llenv.el   
gustav@sp20:../LoadLeveler 23:24:18 !736 $

Having saved this LoadLeveler script on env.ll I have submitted it with

gustav@sp20:../LoadLeveler 23:24:44 !737 $ llsubmit env.ll
submit: The job "sp20.32" has been submitted.
gustav@sp20:../LoadLeveler 23:24:52 !738 $

and then viewed the results of the run as follows:

gustav@sp20:../LoadLeveler 23:25:18 !739 $ cat llenv.out
LoadLeveler variables:
        LOADL_STEP_GROUP=ucs
        LOADL_JOB_NAME=sp20.ucs.indiana.edu.32
        LOADL_STEP_NAME=0
        LOADL_STEP_CLASS=test
        LOADL_STEP_ID=sp20.ucs.indiana.edu.32.0
        LOADL_STEP_OWNER=gustav
        LOADL_ACTIVE=1.3.0.18
        LOADL_STEP_ARGS=
        LOADL_STEP_IN=/dev/null
        LOADLBATCH=yes
        LOADL_STEP_ERR=env.err
        LOADL_STEP_ACCT=
        LOADL_STEP_COMMAND=env.ll
        LOADL_PROCESSOR_LIST=sp17.ucs.indiana.edu 
        LOADL_STARTD_PORT=9611
        LOADL_STEP_NICE=0
        LOADL_STEP_OUT=env.out
        LOADL_STEP_TYPE=SERIAL
        LOADL_STEP_INITDIR=/N/u/gustav/SP/LoadLeveler
gustav@sp20:../LoadLeveler 23:25:22 !740 $