Tutorial: Getting started with Amazon EMR

Overview

With Amazon EMR you can set up a cluster to process and analyze data with big data frameworks in just a few minutes. This tutorial shows you how to launch a sample cluster using Spark, and how to run a simple PySpark script stored in an Amazon S3 bucket. It covers essential Amazon EMR tasks in three main workflow categories: Plan and Configure, Manage, and Clean Up.

You'll find links to more detailed topics as you work through the tutorial, and ideas for additional steps in the Next steps section. If you have questions or get stuck, contact the Amazon EMR team on our Discussion forum.

Prerequisites

• Before you launch an Amazon EMR cluster, make sure you complete the tasks in Setting up Amazon EMR.

Cost

• The sample cluster that you create runs in a live environment. The cluster accrues minimal charges. To avoid additional charges, make sure you complete the cleanup tasks in the last step of this tutorial. Charges accrue at the per-second rate according to Amazon EMR pricing. Charges also vary by Region. For more information, see Amazon EMR pricing.

• Minimal charges might accrue for small files that you store in Amazon S3. Some or all of the charges for Amazon S3 might be waived if you are within the usage limits of the AWS Free Tier. For more information, see Amazon S3 pricing and AWS Free Tier.

Step 1: Plan and configure an Amazon EMR cluster

Prepare storage for Amazon EMR

When you use Amazon EMR, you can choose from a variety of file systems to store input data, output data, and log files. In this tutorial, you use EMRFS to store data in an S3 bucket. EMRFS is an implementation of the Hadoop file system that lets you read and write regular files to Amazon S3. For more information, see Work with storage and file systems.

To create a bucket for this tutorial, follow the instructions in How do I create an S3 bucket? in the Amazon Simple Storage Service Console User Guide. Create the bucket in the same AWS Region where you plan to launch your Amazon EMR cluster. For example, US West (Oregon) us-west-2.

Buckets and folders that you use with Amazon EMR have the following limitations:

• Names can consist of lowercase letters, numbers, periods (.), and hyphens (-).

• Names cannot end in numbers.

• A bucket name must be unique across all AWS accounts.

• An output folder must be empty.

Prepare an application with input data for Amazon EMR

The most common way to prepare an application for Amazon EMR is to upload the application and its input data to Amazon S3. Then, when you submit work to your cluster you specify the Amazon S3 locations for your script and data.

In this step, you upload a sample PySpark script to your Amazon S3 bucket. We've provided a PySpark script for you to use. The script processes food establishment inspection data and returns a results file in your S3 bucket. The results file lists the top ten establishments with the most "Red" type violations.

You also upload sample input data to Amazon S3 for the PySpark script to process. The input data is a modified version of Health Department inspection results in King County, Washington, from 2006 to 2020. For more information, see King County Open Data: Food Establishment Inspection Data. Following are sample rows from the dataset.

name, inspection_result, inspection_closed_business, violation_type, violation_points
100 LB CLAM, Unsatisfactory, FALSE, BLUE, 5
100 PERCENT NUTRICION, Unsatisfactory, FALSE, BLUE, 5
7-ELEVEN #2361-39423A, Complete, FALSE, , 0

To prepare the example PySpark script for EMR

1. Copy the example code below into a new file in your editor of choice.

   import argparse
   
   from pyspark.sql import SparkSession
   
   def calculate_red_violations(data_source, output_uri):
       """
       Processes sample food establishment inspection data and queries the data to find the top 10 establishments
       with the most Red violations from 2006 to 2020.
   
       :param data_source: The URI of your food establishment data CSV, such as 's3://DOC-EXAMPLE-BUCKET/food-establishment-data.csv'.
       :param output_uri: The URI where output is written, such as 's3://DOC-EXAMPLE-BUCKET/restaurant_violation_results'.
       """
       with SparkSession.builder.appName("Calculate Red Health Violations").getOrCreate() as spark:
           # Load the restaurant violation CSV data
           if data_source is not None:
               restaurants_df = spark.read.option("header", "true").csv(data_source)
   
           # Create an in-memory DataFrame to query
           restaurants_df.createOrReplaceTempView("restaurant_violations")
   
           # Create a DataFrame of the top 10 restaurants with the most Red violations
           top_red_violation_restaurants = spark.sql("""SELECT name, count(*) AS total_red_violations 
             FROM restaurant_violations 
             WHERE violation_type = 'RED' 
             GROUP BY name 
             ORDER BY total_red_violations DESC LIMIT 10""")
   
           # Write the results to the specified output URI
           top_red_violation_restaurants.write.option("header", "true").mode("overwrite").csv(output_uri)
   
   if __name__ == "__main__":
       parser = argparse.ArgumentParser()
       parser.add_argument(
           '--data_source', help="The URI for you CSV restaurant data, like an S3 bucket location.")
       parser.add_argument(
           '--output_uri', help="The URI where output is saved, like an S3 bucket location.")
       args = parser.parse_args()
   
       calculate_red_violations(args.data_source, args.output_uri)
   			

2. Save the file as health_violations.py.

3. Upload health_violations.py to Amazon S3 into the bucket you created for this tutorial. For instructions, see Uploading an object to a bucket in the Amazon Simple Storage Service Getting Started Guide.

To prepare the sample input data for EMR

1. Download the zip file, food_establishment_data.zip.

2. Unzip and save food_establishment_data.zip as food_establishment_data.csv on your machine.

3. Upload the CSV file to the S3 bucket that you created for this tutorial. For instructions, see Uploading an object to a bucket in the Amazon Simple Storage Service Getting Started Guide.

For more information about setting up data for EMR, see Prepare input data.

Launch an Amazon EMR cluster

After you prepare a storage location and your application, you can launch a sample Amazon EMR cluster. In this step, you launch an Apache Spark cluster using the latest Amazon EMR release version.

Console

To launch a cluster with Spark installed using Quick Options

1. Open the Amazon EMR console at https://console.aws.amazon.com/elasticmapreduce/.

2. Choose Create cluster to open the Quick Options wizard.

3. Note the default values for Release, Instance type, Number of instances, and Permissions on the Create Cluster - Quick Options page. These fields autofill with values that work for general-purpose clusters. For more information about the Quick Options configuration settings, see Summary of Quick Options.

4. Enter a Cluster name to help you identify the cluster. For example, My First EMR Cluster.

5. Leave Logging enabled, but replace the S3 folder value with the Amazon S3 bucket you created, followed by /logs. For example, s3://DOC-EXAMPLE-BUCKET/logs. Adding /logs creates a new folder called 'logs' in your bucket, where EMR can copy the log files of your cluster.

6. Choose the Spark option under Applications to install Spark on your cluster.

   Note

   Choose the applications you want on your Amazon EMR cluster before you launch the cluster. You can't add or remove applications from a cluster after launch.

7. Choose your EC2 key pair under Security and access.

8. Choose Create cluster to launch the cluster and open the cluster status page.

9. Find the cluster Status next to the cluster name. The status changes from Starting to Running to Waiting as Amazon EMR provisions the cluster. You may need to choose the refresh icon on the right or refresh your browser to see status updates.

Your cluster status changes to Waiting when the cluster is up, running, and ready to accept work. For more information about reading the cluster summary, see View cluster status and details. For information about cluster status, see Understanding the cluster lifecycle.

CLI

To launch a cluster with Spark installed using the AWS CLI

1. Create IAM default roles that you can then use to create your cluster by using the following command.

   aws emr create-default-roles

   For more information about create-default-roles, see the AWS CLI reference.

2. Create a Spark cluster with the following command. Enter a name for your cluster with the --name option, and specify the name of your EC2 key pair with the --ec2-attributes option.

   aws emr create-cluster \
   --name "<My First EMR Cluster>" \
   --release-label <emr-5.35.0> \
   --applications Name=Spark \
   --ec2-attributes KeyName=<myEMRKeyPairName> \
   --instance-type m5.xlarge \
   --instance-count 3 \
   --use-default-roles						

   Note the other required values for --instance-type, --instance-count, and --use-default-roles. These values have been chosen for general-purpose clusters. For more information about create-cluster, see the AWS CLI reference.

   Note

   Linux line continuation characters (\) are included for readability. They can be removed or used in Linux commands. For Windows, remove them or replace with a caret (^).

   You should see output like the following. The output shows the ClusterId and ClusterArn of your new cluster. Note your ClusterId. You use the ClusterId to check on the cluster status and to submit work.

   {
       "ClusterId": "myClusterId",
       "ClusterArn": "myClusterArn"
   }						

3. Check your cluster status with the following command.

   aws emr describe-cluster --cluster-id <myClusterId>						

   You should see output like the following with the Status object for your new cluster.

   {
       "Cluster": {
           "Id": "myClusterId",
           "Name": "My First EMR Cluster",
           "Status": {
               "State": "STARTING",
               "StateChangeReason": {
                   "Message": "Configuring cluster software"
               }
           }
        }
   }					

   The State value changes from STARTING to RUNNING to WAITING as Amazon EMR provisions the cluster.

Cluster status changes to WAITING when a cluster is up, running, and ready to accept work. For information about cluster status, see Understanding the cluster lifecycle.

Step 2: Manage your Amazon EMR cluster

Submit work to Amazon EMR

After you launch a cluster, you can submit work to the running cluster to process and analyze data. You submit work to an Amazon EMR cluster as a step. A step is a unit of work made up of one or more actions. For example, you might submit a step to compute values, or to transfer and process data. You can submit steps when you create a cluster, or to a running cluster. In this part of the tutorial, you submit health_violations.py as a step to your running cluster. To learn more about steps, see Submit work to a cluster.

Console

To submit a Spark application as a step using the console

1. Open the Amazon EMR console at https://console.aws.amazon.com/elasticmapreduce/.

2. Select the name of your cluster from the Cluster List. The cluster state must be Waiting.

3. Choose Steps, and then choose Add step.

4. Configure the step according to the following guidelines:

   • For Step type, choose Spark application. You should see additional fields for Deploy Mode, Spark-submit options, and Application location appear.

   • For Name, leave the default value or type a new name. If you have many steps in a cluster, naming each step helps you keep track of them.

   • For Deploy mode, leave the default value Cluster. For more information about Spark deployment modes, see Cluster mode overview in the Apache Spark documentation.

   • Leave the Spark-submit options field blank. For more information about spark-submit options, see Launching applications with spark-submit.

   • For Application location, enter the location of your health_violations.py script in Amazon S3. For example, s3://DOC-EXAMPLE-BUCKET/health_violations.py.

   • In the Arguments field, enter the following arguments and values:

     --data_source s3://DOC-EXAMPLE-BUCKET/food_establishment_data.csv
     --output_uri s3://DOC-EXAMPLE-BUCKET/myOutputFolder						

     Replace s3://DOC-EXAMPLE-BUCKET/food_establishment_data.csv with the S3 URI of the input data you prepared in Prepare an application with input data for Amazon EMR.

     Replace DOC-EXAMPLE-BUCKET with the name of the bucket you created for this tutorial, and myOutputFolder with a name for your cluster output folder.

   • For Action on failure, accept the default option Continue so that if the step fails, the cluster continues to run.

5. Choose Add to submit the step. The step should appear in the console with a status of Pending.

6. Check for the step status to change from Pending to Running to Completed. To refresh the status in the console, choose the refresh icon to the right of the Filter. The script takes about one minute to run.

You will know that the step finished successfully when the status changes to Completed.

CLI

To submit a Spark application as a step using the AWS CLI

1. Make sure you have the ClusterId of the cluster you launched in Launch an Amazon EMR cluster. You can also retrieve your cluster ID with the following command.

   aws emr list-clusters --cluster-states WAITING							

2. Submit health_violations.py as a step with the add-steps command and your ClusterId.

   • You can specify a name for your step by replacing "My Spark Application". In the Args array, replace s3://DOC-EXAMPLE-BUCKET/health_violations.py with the location of your health_violations.py application.

   • Replace s3://DOC-EXAMPLE-BUCKET/food_establishment_data.csv with the S3 location of your food_establishment_data.csv dataset.

   • Replace s3://DOC-EXAMPLE-BUCKET/MyOutputFolder with the S3 path of your designated bucket and a name for your cluster output folder.

   • ActionOnFailure=CONTINUE means the cluster continues to run if the step fails.

   aws emr add-steps \
   --cluster-id <myClusterId> \
   --steps Type=Spark,Name="<My Spark Application>",ActionOnFailure=CONTINUE,Args=[<s3://DOC-EXAMPLE-BUCKET/health_violations.py>,--data_source,<s3://DOC-EXAMPLE-BUCKET/food_establishment_data.csv>,--output_uri,<s3://DOC-EXAMPLE-BUCKET/MyOutputFolder>]							

   For more information about submitting steps using the CLI, see the AWS CLI Command Reference.

   After you submit the step, you should see output like the following with a list of StepIds. Since you submitted one step, you will see just one ID in the list. Copy your step ID. You use your step ID to check the status of the step.

   {
       "StepIds": [
           "s-1XXXXXXXXXXA"
       ]
   }											

3. Query the status of your step with the describe-step command.

   aws emr describe-step --cluster-id <myClusterId> --step-id <s-1XXXXXXXXXXA>							

   You should see output like the following with information about your step.

   {
       "Step": {
           "Id": "s-1XXXXXXXXXXA",
           "Name": "My Spark Application",
           "Config": {
               "Jar": "command-runner.jar",
               "Properties": {},
               "Args": [
                   "spark-submit",
                   "s3://DOC-EXAMPLE-BUCKET/health_violations.py",
                   "--data_source",
                   "s3://DOC-EXAMPLE-BUCKET/food_establishment_data.csv",
                   "--output_uri",
                   "s3://DOC-EXAMPLE-BUCKET/myOutputFolder"
               ]
           },
           "ActionOnFailure": "CONTINUE",
           "Status": {
               "State": "COMPLETED"
           }
       }
   }						

   The State of the step changes from PENDING to RUNNING to COMPLETED as the step runs. The step takes about one minute to run, so you might need to check the status a few times.

You will know that the step was successful when the State changes to COMPLETED.

For more information about the step lifecycle, see Running steps to process data.

View results

After a step runs successfully, you can view its output results in your Amazon S3 output folder.

To view the results of health_violations.py

1. Open the Amazon S3 console at https://console.aws.amazon.com/s3/.

2. Choose the Bucket name and then the output folder that you specified when you submitted the step. For example, DOC-EXAMPLE-BUCKET and then myOutputFolder.

3. Verify that the following items appear in your output folder:

   • A small-sized object called _SUCCESS.

   • A CSV file starting with the prefix part- that contains your results.

4. Choose the object with your results, then choose Download to save the results to your local file system.

5. Open the results in your editor of choice. The output file lists the top ten food establishments with the most red violations. The output file also shows the total number of red violations for each establishment.

   The following is an example of health_violations.py results.

   name, total_red_violations
   SUBWAY, 322
   T-MOBILE PARK, 315
   WHOLE FOODS MARKET, 299
   PCC COMMUNITY MARKETS, 251
   TACO TIME, 240
   MCDONALD'S, 177
   THAI GINGER, 153
   SAFEWAY INC #1508, 143
   TAQUERIA EL RINCONSITO, 134
   HIMITSU TERIYAKI, 128				

For more information about Amazon EMR cluster output, see Configure an output location.

(Optional) Connect to your running Amazon EMR cluster

When you use Amazon EMR, you may want to connect to a running cluster to read log files, debug the cluster, or use CLI tools like the Spark shell. Amazon EMR lets you connect to a cluster using the Secure Shell (SSH) protocol. This section covers how to configure SSH, connect to your cluster, and view log files for Spark. For more information about connecting to a cluster, see Authenticate to Amazon EMR cluster nodes.

Authorize SSH connections to your cluster

Before you connect to your cluster, you need to modify your cluster security groups to authorize inbound SSH connections. Amazon EC2 security groups act as virtual firewalls to control inbound and outbound traffic to your cluster. When you created your cluster for this tutorial, Amazon EMR created the following security groups on your behalf:

ElasticMapReduce-master

The default Amazon EMR managed security group associated with the master node. In an Amazon EMR cluster, the master node is an Amazon EC2 instance that manages the cluster.

ElasticMapReduce-slave

The default security group associated with core and task nodes.

To allow SSH access for trusted sources for the ElasticMapReduce-master security group

To edit your security groups, you must have permission to manage security groups for the VPC that the cluster is in. For more information, see Changing Permissions for an IAM User and the Example Policy that allows managing EC2 security groups in the IAM User Guide.

1. Open the Amazon EMR console at https://console.aws.amazon.com/elasticmapreduce/.

2. Choose Clusters.

3. Choose the Name of the cluster you want to modify.

4. Choose the Security groups for Master link under Security and access.

5. Choose ElasticMapReduce-master from the list.

6. Choose the Inbound rules tab and then Edit inbound rules.

7. Check for an inbound rule that allows public access with the following settings. If it exists, choose Delete to remove it.

   • Type

     SSH

   • Port

     22

   • Source

     Custom 0.0.0.0/0

   Warning

   Before December 2020, the ElasticMapReduce-master security group had a pre-configured rule to allow inbound traffic on Port 22 from all sources. This rule was created to simplify initial SSH connections to the master node. We strongly recommend that you remove this inbound rule and restrict traffic to trusted sources.

8. Scroll to the bottom of the list of rules and choose Add Rule.

9. For Type, select SSH.

   Selecting SSH automatically enters TCP for Protocol and 22 for Port Range.

10. For source, select My IP to automatically add your IP address as the source address. You can also add a range of Custom trusted client IP addresses, or create additional rules for other clients. Many network environments dynamically allocate IP addresses, so you might need to update your IP addresses for trusted clients in the future.

11. Choose Save.

12. Optionally, choose ElasticMapReduce-slave from the list and repeat the steps above to allow SSH client access to core and task nodes.

Connect to your cluster using the AWS CLI

Regardless of your operating system, you can create an SSH connection to your cluster using the AWS CLI.

To connect to your cluster and view log files using the AWS CLI

1. Use the following command to open an SSH connection to your cluster. Replace <mykeypair.key> with the full path and file name of your key pair file. For example, C:\Users\<username>\.ssh\mykeypair.pem.

   aws emr ssh --cluster-id <j-2AL4XXXXXX5T9> --key-pair-file <~/mykeypair.key>						

2. Navigate to /mnt/var/log/spark to access the Spark logs on your cluster's master node. Then view the files in that location. For a list of additional log files on the master node, see View log files on the master node.

   cd /mnt/var/log/spark
   ls

Step 3: Clean up your Amazon EMR resources

Terminate your cluster

Now that you've submitted work to your cluster and viewed the results of your PySpark application, you can terminate the cluster. Terminating a cluster stops all of the cluster's associated Amazon EMR charges and Amazon EC2 instances.

When you terminate a cluster, Amazon EMR retains metadata about the cluster for two months at no charge. Archived metadata helps you clone the cluster for a new job or revisit the cluster configuration for reference purposes. Metadata does not include data that the cluster writes to S3, or data stored in HDFS on the cluster.

Note

The Amazon EMR console does not let you delete a cluster from the list view after you terminate the cluster. A terminated cluster disappears from the console when Amazon EMR clears its metadata.

Console

To terminate the cluster using the console

1. Open the Amazon EMR console at https://console.aws.amazon.com/elasticmapreduce/.

2. Choose Clusters, then choose the cluster you want to terminate. For example, My First EMR Cluster.

3. Choose Terminate to open the Terminate cluster prompt.

4. Choose Terminate in the open prompt. Depending on the cluster configuration, termination may take 5 to 10 minutes. For more information about terminating Amazon EMR clusters, see Terminate a cluster.

   Note

   If you followed the tutorial closely, termination protection should be off. Cluster termination protection prevents accidental termination. If termination protection is on, you will see a prompt to change the setting before terminating the cluster. Choose Change, then Off.

CLI

To terminate the cluster using the AWS CLI

1. Initiate the cluster termination process with the following command. Replace <myClusterId> with the ID of your sample cluster. The command does not return output.

   aws emr terminate-clusters --cluster-ids <myClusterId>

2. To check that the cluster termination process is in progress, check the cluster status with the following command.

   aws emr describe-cluster --cluster-id <myClusterId>									

   Following is example output in JSON format. The cluster Status should change from TERMINATING to TERMINATED. Termination may take 5 to 10 minutes depending on your cluster configuration. For more information about terminating an Amazon EMR cluster, see Terminate a cluster.

   {
       "Cluster": {
           "Id": "j-xxxxxxxxxxxxx",
           "Name": "My Cluster Name",
           "Status": {
               "State": "TERMINATED",
               "StateChangeReason": {
                   "Code": "USER_REQUEST",
                   "Message": "Terminated by user request"
               }
           }
       }
   }

Delete S3 resources

To avoid additional charges, you should delete your Amazon S3 bucket. Deleting the bucket removes all of the Amazon S3 resources for this tutorial. Your bucket should contain:

• The PySpark script

• The input dataset

• Your output results folder

• Your log files folder

You might need to take extra steps to delete stored files if you saved your PySpark script or output in a different location.

Note

Your cluster must be terminated before you delete your bucket. Otherwise, you may not be allowed to empty the bucket.

To delete your bucket, follow the instructions in How do I delete an S3 bucket? in the Amazon Simple Storage Service User Guide.

Next steps

You have now launched your first Amazon EMR cluster from start to finish. You have also completed essential EMR tasks like preparing and submitting big data applications, viewing results, and terminating a cluster.

Use the following topics to learn more about how you can customize your Amazon EMR workflow.

Explore big data applications for Amazon EMR

Discover and compare the big data applications you can install on a cluster in the Amazon EMR Release Guide. The Release Guide details each EMR release version and includes tips for using frameworks such as Spark and Hadoop on Amazon EMR.

Plan cluster hardware, networking, and security

In this tutorial, you created a simple EMR cluster without configuring advanced options. Advanced options let you specify Amazon EC2 instance types, cluster networking, and cluster security. For more information about planning and launching a cluster that meets your requirements, see Plan and configure clusters and Security in Amazon EMR.

Manage clusters

Dive deeper into working with running clusters in Manage clusters. To manage a cluster, you can connect to the cluster, debug steps, and track cluster activities and health. You can also adjust cluster resources in response to workload demands with EMR managed scaling.

Use a different interface

In addition to the Amazon EMR console, you can manage Amazon EMR using the AWS Command Line Interface, the web service API, or one of the many supported AWS SDKs. For more information, see Management interfaces.

You can also interact with applications installed on Amazon EMR clusters in many ways. Some applications like Apache Hadoop publish web interfaces that you can view. For more information, see View web interfaces hosted on Amazon EMR clusters.

Browse the EMR technical blog

For sample walkthroughs and in-depth technical discussion of new Amazon EMR features, see the AWS big data blog.