EMR CLI Examples

This is a set of examples that show how EMR CLI can be used to easily deploy a variety of different jobs to EMR Serverless and EMR on EC2.

Pre-requisities

• An EMR Serverless application, job role and S3 bucket
• An EMR on EC2 cluster
• The emr CLI installed via pip install emr-cli

If you don't have EMR Serverless setup, you can use the emr bootstrap command to provision an S3 bucket, job role, and application.

For EMR on EC2, we'll just create a Spark cluster in the console.

We'll set a variety of environment variables to be used throughout the examples.

APPLIATION_ID=<EMR_SERVERLESS_APPLICATION_ID>
JOB_ROLE_ARN=arn:aws:iam::<ACCOUNT_ID>:role/<JOB_ROLE>
S3_BUCKET=<S3_BUCKET_NAME>
CLUSTER_ID=<EMR_EC2_CLUSTER_ID>

Single file test

Single file test is a single .py file that prints out hello.

single-file-test
└── entrypoint.py

1 directory, 1 file

This command, "builds" the project, which in this case does nothing. It then copies it up to the s3-code-uri specified and starts a new EMR Serverless job.

emr run \
    --entry-point entrypoint.py \
    --application-id ${APPLICATION_ID} \
    --job-role ${JOB_ROLE_ARN} \
    --s3-code-uri s3://${S3_BUCKET}/tmp/emr-cli-demo/$(basename $PWD) \
    --build \
    --wait

We can run the same code on EMR on EC2. No need to --build again as we're already deployed.

emr run \
    --entry-point entrypoint.py \
    --cluster-id ${CLUSTER_ID} \
    --s3-code-uri s3://${S3_BUCKET}/tmp/emr-cli-demo/$(basename $PWD) \
    --wait --show-stdout

Multi file test

The next project uses a standard Python project structure. It's a slightly more complex Spark job that reads a CSV file from the NOAA GSOD open dataset.

Note Because we access data in S3, your EMR Serverless application either needs to be in the us-east-1 region or created with a VPC.

multi-file-test
├── entrypoint.py
└── jobs
    ├── __init__.py
    └── job1.py

2 directories, 3 files

We'll run the same exact command, just in the multi-file-test directory.

emr run \
    --entry-point entrypoint.py \
    --application-id ${APPLICATION_ID} \
    --job-role ${JOB_ROLE_ARN} \
    --s3-code-uri s3://${S3_BUCKET}/tmp/emr-cli-demo/$(basename $PWD) \
    --build \
    --wait

This time, we notice that a dist/ directory is created with our job modules.

dist
└── pyfiles.zip

1 directory, 1 file

When emr run is called, it automatically detects this is a multi-module Python project, zips up the jobs/ directory, and uploads it to S3.

Then when the EMR Serverless job or EMR on EC2 step is created, it sends the proper spark-submit settings.

emr run \
    --entry-point entrypoint.py \
    --cluster-id ${CLUSTER_ID} \
    --s3-code-uri s3://${S3_BUCKET}/tmp/emr-cli-demo/$(basename $PWD) \
    --wait

Python build system

Modern Python projects can contain a pyproject.toml file. The EMR CLI supports building these projects and can even initialize a default project for you with the init command.

emr init pyproject-test

❯ emr init pyproject-test
[emr-cli]: Initializing project in pyproject-test
[emr-cli]: Project initialized.

pyproject-test
├── Dockerfile
├── entrypoint.py
├── jobs
│   └── extreme_weather.py
└── pyproject.toml

2 directories, 4 files

Notice that there's a Dockerfile in this directory - Docker is used by the emr package command to build a virtualenv compatible with Amazon Linux. This is required for certain Python depenencies that have operating system-specific functionality.

We can indepedently build the project using the emr package command.

emr package --entry-point entrypoint.py 

Again, we see our job dependencies in the dist/ directory.

dist/
└── pyspark_deps.tar.gz

1 directory, 1 file

Notice that instead of a simple pyfiles.zip file, we have pyspark_deps.tar.gz. This is a bundled virtual environment that includes

And we can also deploy it to S3 using the emr deploy command.

emr deploy \
    --entry-point entrypoint.py \
    --s3-code-uri s3://${S3_BUCKET}/tmp/emr-cli-demo/$(basename $PWD)

A simple emr run command is all we need to run the deployed code in EMR Serverless or EMR on EC2.

emr run \
    --entry-point entrypoint.py \
    --application-id ${APPLICATION_ID} \
    --job-role ${JOB_ROLE_ARN} \
    --s3-code-uri s3://${S3_BUCKET}/tmp/emr-cli-demo/$(basename $PWD)

I left off the --wait this time because this example job takes longer to run, so the emr run command exits immediately after submitting the job.

Same goes for EMR on EC2.

emr run \
    --entry-point entrypoint.py \
    --cluster-id ${CLUSTER_ID} \
    --s3-code-uri s3://${S3_BUCKET}/tmp/emr-cli-demo/$(basename $PWD)

Python Poetry support

Finally, Poetry is a popular Python dependency management and packaging tool. The EMR CLI supports creating an example PySpark project with Poetry as well as bundling and deploying Poetry projects.

You can use the emr init --project-type poetry command to create a sample Poetry project in your directory of choice, or you can also use the emr init --dockerfile command to create a Dockerfile in your local directory that supports packaging Poetry projects.

emr init --project-type poetry poetry-test/

Just make sure you do a poetry install in order to generate the poetry.lock file. This file is used by the EMR CLI to auto-detect a Poetry project.

cd poetry-test
poetry install

Warning We specify Python 3.7.10 as that's what is used by default in EMR Serverless. You may experience different results or errors when using another Python version.

When we run emr package or emr run with the --deploy flag, a different stage in the Dockerfile is used that uses the Poetry Bundle plugin to bundle up your job's dependencies.

emr run \
    --entry-point entrypoint.py \
    --application-id ${APPLICATION_ID} \
    --job-role ${JOB_ROLE_ARN} \
    --s3-code-uri s3://${S3_BUCKET}/tmp/emr-cli-demo/$(basename $PWD) \
    --build \
    --wait

There's really no difference here in the spark-submit parameters or how the job is run. It's really the difference in the build commands.

If your EMR cluster is running the same version as your EMR Serverless application (and sometimes, even if it's not), you can again run the same code on EMR on EC2.

emr run \
    --entry-point entrypoint.py \
    --cluster-id ${CLUSTER_ID} \
    --s3-code-uri s3://${S3_BUCKET}/tmp/emr-cli-demo/$(basename $PWD)

Spark SQL + Glue Data Catalog support

If you're using SparkSQL wrapped in a Python script, that's also similar to the Single file test, but you need to add an extra --spark-submit-options argument and ensure you use enableHiveSupport() when creating your SparkSession object.

For example:

from pyspark.sql import SparkSession

spark = (
    SparkSession.builder.appName("SparkSQL")
    .enableHiveSupport()
    .getOrCreate()
)

Assuming we have a simple sql.py file that just shows our databases, we can deploy and run it like this:

emr run \
    --job-name sparksql-glue \
    --entry-point sql.py \
    --application-id ${APPLICATION_ID} \
    --job-role ${JOB_ROLE_ARN} \
    --s3-code-uri s3://${S3_BUCKET}/tmp/emr-cli-demo/$(basename $PWD) \
    --build \
    --wait \
    --s3-logs-uri s3://${S3_BUCKET}/logs/ \
    --show-stdout \
    --spark-submit-opts "--conf spark.hadoop.hive.metastore.client.factory.class=com.amazonaws.glue.catalog.metastore.AWSGlueDataCatalogHiveClientFactory"

Note: The command above also makes use of the --show-stdout and --s3-logs-uri flags added in the v0.0.9 emr-cli release.

Conclusion

That's it for now! Thanks for joining as we explored the varied ways of deploying PySpark code to EMR and how the EMR CLI can make it all as easy as a single command.