The Open OnDemand Job Composer enables users to create job scripts and submit them without ever using the command line. This is paricularly helpful for new users who have never opened a terminal or are unfamiliar with Linux command line behavior. However, some knowledge of Slurm and ARCC’s required Slurm directives is needed to successfully submit jobs on MedicineBow. Discussed in this section of the workshop is the use of the Job Composer and common issues that arise with it.

First Look at the Job Composer

When opening the Job Composer for the first time, there are a few pop up prompts to follow to get started creating a job. There are also two items in the top menu 1) for Job management and 2) for job templates. Notice that the “New Job” button allows user to select a previously created job with the path, or from a Default Template as well as a new one if there is a job in the selections below.

Create a Job With a Template

If someone has never created a batch job in Slurm before, a template is a good place to get started into seeing how one would look like. In this example, we will create a Default Template and then edit it in the steps below.

After clicking the “New Job” Button and selecting the “Default Template” option, we are presented with a new box on the right of the first look. Notice the parameters already set:

Job Name
Account
Along with script location and name
As well as a preview of what the job looks like

This default will not run on ARCC systems “as-is”. Edits will be required.

Job Editor

When we click the light blue button on the bottom of the right box, we get a new window to pop up with a text editor-like appearance. If we then look at ARCC’s documentation on Required Inputs, we know what to add to get a job to run by adding the account and time Slurm directives.

If we click save and go back to the Job Composer page, we should see our changes in the preview.

Job Options

Now that our job will run, we still might need to make some changes to the job options that will work best for us. If we click the “Job Options” button on the left box we get presented with a new view:

We can rename the job to “Hello_world_Template” that makes more sense for us to find later
Leave cluster and job script fields as the default because that is the system we want and the file we just editied
We can add account here instead of in the script, but it’s just a good practice to have it in the script

Job Submission

With all of the edits made, we can now submit the job to the cluster to run. The steps to do so are:

Make sure the Job is selected in the left box
Click the green “Submit” button

If we refresh the page, we see in the left box that this simple job has been completed and a file for our output was created on the right box

In Conclusion

This module was a simple tutorial for using the Job Composer in Open OnDemand. This tool helps to send jobs to the MedicineBow cluster without the need for using a terminal. That said, the concepts for job submission with Slurm still apply to this tool and it is important to understand what each are doing, but most importantly:

ARCC’s required inputs
Other Slurm directives that are important to the success of the job
How to use Lmod to load software
Awareness of where the locations on the system where the script is created and output are placed

If used wisely, the Open OnDemand Job Composer can be an easy-to-use tool for creating jobs on MedicineBow and the other tutorials on Intro to Linux, Text Editors, Lmod, and Job Submission are extremely beneficial for the successful use of the tool.

Finally The End

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