Apache Spark has become a go-to solution for big data processing, thanks to its robust architecture and scalability. PySpark, the Python API for Spark, offers a convenient way to leverage Spark’s capabilities using Python. However, managing and submitting PySpark jobs in a distributed environment can be challenging. This article delves into the process of submitting PySpark jobs through a REST API, providing a seamless and efficient method for job management in distributed systems.
What is REST API in Spark?
The REST API in Apache Spark allows for remote job submission, status tracking, and cancellation through standard HTTP methods. This API is part of Spark’s standalone cluster mode and provides an interface for interacting with the Spark cluster.
Setting Up the Environment
Before submitting jobs via the REST API, ensure you have the following:
- Apache Spark installed and configured in standalone cluster mode.
- PySpark available in your environment.
- Access to the Spark Master’s REST URL (usually
http://[spark-master-host]:6066).
Submitting a PySpark Job via REST API
Step 1: Preparing the PySpark Script
First, prepare your PySpark script. For example:
example_job.py:
from pyspark.sql import SparkSession
if __name__ == "__main__":
spark = SparkSession.builder.appName("SimpleApp").getOrCreate()
df = spark.read.csv("path/to/csv")
df.show()
spark.stop()
Step 2: Packaging the Application
Package your PySpark application into a ZIP or a JAR file. For Python scripts, a ZIP file is preferable.
Step 3: Submitting the Job
Use a tool like curl to submit the job to the Spark REST API.
Example Request:
curl -X POST http://[spark-master-host]:6066/v1/submissions/create \
--header "Content-Type:application/json;charset=UTF-8" \
--data '{
"action": "CreateSubmissionRequest",
"appResource": "file:/path/to/your/example_job.zip",
"clientSparkVersion": "2.4.0",
"appArgs": [],
"environmentVariables": {
"SPARK_ENV_LOADED": "1"
},
"mainClass": "org.apache.spark.deploy.PythonRunner",
"sparkProperties": {
"spark.jars": "file:/path/to/your/example_job.zip",
"spark.app.name": "SimpleApp",
"spark.master": "spark://[spark-master-host]:7077"
}
}'
Replace [spark-master-host] with your Spark Master’s host name and update the paths to the ZIP file accordingly.
Step 4: Monitoring the Job
Upon successful submission, the REST API will return a submission ID. Use this ID to monitor the job status.
Example Status Request:
curl http://[spark-master-host]:6066/v1/submissions/status/[submission-id]
Understanding the Output
The REST API provides JSON responses. A successful submission response includes the submission ID and message indicating successful submission. The status request returns the current state of the job, such as RUNNING, FINISHED, or FAILED, along with specific logs or error messages.
Spark important urls to refer
