scripts for using spark on janelia's cluster
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README.md
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spark-janelia

README.md

Spark Janelia

Scripts, utilities, and community for launching Spark on the Janelia Research Center cluster. If you have questions you can come hang out in the public freeman lab chatroom on gitter (or #thefreemanlab on freenode).


Using Spark

These scripts automate many of the tasks required to start and manage a Spark job.

Initial setup

SSH in to one of Janelia's cluster login nodes (see Scientific Computing for more information).

ssh login2.int.janelia.org

If you have never done so, set up keyless SSH

ssh-keygen -t dsa

Accept all of the default settings by hitting "return" three times. Then continue with

cd .ssh
cat id_dsa.pub >> authorized_keys

Navigate to a location in your home directory where you will store these scripts, then call

git clone https://github.com/freeman-lab/spark-janelia

Add a line with this location to your bash profile (usually located in ~/.bash_profile)

export PATH=/path/to/spark-janelia:$PATH

While doing this, also add this line to point your PATH to a recent version of Python:

export PATH=/usr/local/python-2.7.11/bin/:$PATH

If you want to continue in the same session, source your profile with source ~/.bash_profile.

Starting a cluster

While logged in to one of Janelia cluster's login nodes, submit a request to run a group of nodes as a Spark cluster using:

spark-janelia launch -n <number_of_nodes>

Each node has 16 cores and 100GB of RAM for Spark to use. You should target the number of nodes you request based on the size of the data you are working with or the amount of neccessary computation (or both). A good rule of thumb is to use enough nodes so the total amount of RAM is about twice the total size of your data set. Check the status of your request using the qstat command. When the status is listed as r (for "ready"), proceed.

Every Spark cluster has a unique node designated as the "driver" from which all computations are initiated. To log in to the driver for your Spark cluster, use:

spark-janelia login

You can now run Spark applications as described below.

Running basic jobs

To start the Spark interactive shell in Python call

spark-janelia start

This will start a shell with Spark running and its modules available.

To start the Spark interactive shell in Scala call

spark-janelia start-scala

And to submit a Spark application to run call

spark-janelia submit -s <submit_arguments>

Where submit_arguments is a string of arguments you would normally pass to spark-submit, as described in the Spark documentation.

Running a Spark application with automatic shut down of the Spark cluster after completion

If you want to run an application with unknown runtime it will be helpful to have the Spark cluster shut down automatically after completion of the application.

spark-janelia <args> lsd -s <submit_arguments>

will submit your application and delete the cluter job, once it has finished. lsd is short for launch-submit-and-destroy and the meaning of submit_arguments is along the lines of spark-janelia submit. For an example of how to set up a Python script for this workflow, see the example in examples/lsd-example.py.


Using the Jupyter notebook

When running Spark in Python, the Jupyter notebook is a great way to run analyses and inspect and visualize results. This requires no extra setup, simple add the -b flag when starting Python:

Now, when starting Spark, add the -b flag, as in:

spark-janelia start -b

Instead of opening a shell, this will launch a Jupyter Notebook server on the driver. You will see a website address printed next to View your notebooks at.... Go to this address in a web browser. Your browser will complain that the connection is not trusted; just ignore and proceed.

When prompted, enter the password you chose above. You should now have a graphical interface to the directory from which you launched the IPython Notebook server. From here you can create a new notebook or edit a previously-existing one.

To shut down the IPython Notebook server, return to the terminal where the server is running and type Ctrl+C+C.

NOTE: You can't run Spark jobs in multiple notebooks at once. If you start one notebook, then start another, nothing will execute in the second one until you shutdown the first one (by clicking the shutdown button in the notebook browser).

If you would like to use the Jupyter notebook for non-Spark related work, we also provide a script for configuring the notebook for general use on the cluster. As a one time operation, call this script

setup-notebook-janelia

This will configure your Jupyer Notebook settings to be compatible with Janelia's cluster. Then, from any node, you can start a server with

jupyter notebook

Shutting down

When you are finished with all of your jobs, log out of the driver with the simple command exit in the command line. Finally, release your nodes with

spark-janelia destroy

You can check that these nodes have successfully been released with the qstat command.


Questions and comments

Many Spark users at Janelia hang out in the freeman lab gitter chat rooom. If you have questions or comments, or just want to join the conversation, please drop by!