FileNotFound When Creating SparkContext with YARN without HDFS: A Step-by-Step Guide to Resolve the Error

Are you tired of encountering the dreaded FileNotFound error when trying to create a SparkContext with YARN without HDFS? Look no further! In this comprehensive guide, we’ll take you through the troubleshooting process, providing clear and direct instructions to resolve this frustrating issue.

Understanding the Error

The FileNotFound error typically occurs when Spark is unable to find the Jar files or configuration files required to launch the application. When using YARN without HDFS, Spark relies on the local file system for storing and retrieving files. However, if the necessary files are not present or accessible, Spark throws the FileNotFound exception.

Cause 1: Missing Jar Files

One of the most common causes of the FileNotFound error is the absence of the Spark Jar files. When submitting a Spark application to YARN, Spark needs to access the Jar files containing the application code and dependencies. If these files are not present in the expected location, the error occurs.

Solution:

To resolve this issue, ensure that the Spark Jar files are present in the correct location. You can do this by:

• Verifying that the Spark installation is correct and complete.
• Checking that the Jar files are present in the $SPARK_HOME/jars directory.
• Setting the spark.jars property in your SparkConf to point to the correct location.

Example code snippet:

val conf = new SparkConf()
  .setMaster("yarn")
  .set("spark.jars", "/path/to/spark/jars")
  .setAppName("My Spark App")

val sc = new SparkContext(conf)

Cause 2: Inaccessible Configuration Files

Another common cause of the FileNotFound error is the inaccessibility of configuration files. Spark relies on configuration files, such as spark-defaults.conf and yarn-site.xml, to determine the application’s behavior and YARN’s configuration.

Solution:

To resolve this issue, ensure that:

• The configuration files are present in the correct location.
• The files are readable by the Spark application.
• The files are correctly configured for YARN mode.

Example configuration file snippet:

spark.master                  yarn
spark.yarn.jar                /path/to/spark/assembly/jar
spark.yarn.executor.memory    1g
spark.yarn.executor.cores    2

Troubleshooting Steps

Follow these steps to troubleshoot the FileNotFound error:

1. Verify the Spark installation and Jar files.
2. Check the configuration files for correctness and accessibility.
3. Verify the SparkConf settings, especially the spark.jars property.
4. Check the YARN logs for any error messages or warnings.
5. Try submitting the Spark application with the --verbose flag to gather more detailed logs.

Common Pitfalls and Solutions

Pitfall	Solution
Missing spark-assembly.jar	Build and include the spark-assembly.jar in the $SPARK_HOME/assembly directory.
Incorrect spark.jars property	Verify that the spark.jars property points to the correct location of the Jar files.
Inaccessible configuration files	Ensure that the configuration files are present in the correct location and are readable by the Spark application.
YARN configuration issues	Verify that the YARN configuration files, such as yarn-site.xml, are correctly configured for YARN mode.

Conclusion

By following this comprehensive guide, you should be able to resolve the FileNotFound error when creating a SparkContext with YARN without HDFS. Remember to verify the Spark installation, Jar files, and configuration files, as well as troubleshoot the issue using the steps outlined above. With persistence and patience, you’ll be able to overcome this frustrating error and successfully run your Spark application on YARN.

So, the next time you encounter the FileNotFound error, don’t panic! Instead, follow this guide, and you’ll be well on your way to resolving the issue and getting your Spark application up and running.

Happy Spark-ing!

Here is the requested HTML code with 5 questions and answers about “FileNotFound when creating SparkContext with YARN without HDFS”:

Frequently Asked Question

Get answers to the most frequently asked questions about FileNotFound when creating SparkContext with YARN without HDFS.