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Amazon EMR
Management Guide

Upload Data to Amazon S3

For information on how to upload objects to Amazon S3, see Add an Object to Your Bucket in the Amazon Simple Storage Service Getting Started Guide. For more information about using Amazon S3 with Hadoop, see http://wiki.apache.org/hadoop/AmazonS3.

Create and Configure an Amazon S3 Bucket

Amazon EMR uses the AWS SDK for Java with Amazon S3 to store input data, log files, and output data. Amazon S3 refers to these storage locations as buckets. Buckets have certain restrictions and limitations to conform with Amazon S3 and DNS requirements. For more information, see Bucket Restrictions and Limitations in the Amazon Simple Storage Service Developer Guide.

This section shows you how to use the Amazon S3 AWS Management Console to create and then set permissions for an Amazon S3 bucket. You can also create and set permissions for an Amazon S3 bucket using the Amazon S3 API or AWS CLI. You can also use Curl along with a modification to pass the appropriate authentication parameters for Amazon S3.

See the following resources:

Note

If you enable logging for a bucket, it enables only bucket access logs, not Amazon EMR cluster logs.

During bucket creation or after, you can set the appropriate permissions to access the bucket depending on your application. Typically, you give yourself (the owner) read and write access and give authenticated users read access.

Required Amazon S3 buckets must exist before you can create a cluster. You must upload any required scripts or data referenced in the cluster to Amazon S3. The following table describes example data, scripts, and log file locations.

Best Practices

The following are recommendations for using Amazon S3 Buckets with EMR clusters.

Enable Versioning

Versioning is a recommended configuration for your Amazon S3 bucket. By enabling versioning, you ensure that even if data is unintentionally deleted or overwritten it can be recovered. For more information, go to Using Versioning in the Amazon Simple Storage Service Developer Guide.

Consider Lifecycle Management

Lifecycle Management in Amazon S3 allows you to create rules which control the storage class and lifetime of your objects. For more information, see Object Lifecycle Management

Clean Up Failed Multipart Uploads and Version Markers

EMR cluster components use multipart uploads via the AWS SDK for Java with Amazon S3 APIs to write log files and output data to Amazon S3 by default. For information about changing this configuration, see Configure Multipart Upload for Amazon S3. Amazon EMR does not automatically manage incomplete multipart uploads. Sometimes the upload of a large file can result in an incomplete Amazon S3 multipart upload. When a multipart upload is unable to complete successfully, the in-progress multipart upload continues to occupy your bucket and incurs storage charges. We recommend that for buckets you use with Amazon EMR, you use a lifecycle rule to remove incomplete multipart uploads three days after the upload initiation date. For more information, see Aborting Incomplete Multipart Uploads Using a Bucket Lifecycle Policy.

When deleting an object in a versioned bucket a delete marker is created. If all previous versions of the object subsequently expire, an expired object delete marker is left within the bucket. While there is no charge for these delete markers, removing the expired delete markers can improve the performance of LIST requests. It is recommended that for versioned buckets you will use with Amazon EMR, you should also enable a rule to remove expired object delete markers. For more information, see Lifecycle Configuration for a Bucket with Versioning in the Amazon Simple Storage Service Console User Guide.

Performance best practices

Depending on your workloads, specific types of usage of EMR clusters and applications on those clusters can result in a high number of requests against a bucket. For more information, see Request Rate and Performance Considerations in the Amazon Simple Storage Service Developer Guide.

Configure Multipart Upload for Amazon S3

Amazon EMR supports Amazon S3 multipart upload through the AWS SDK for Java. Multipart upload lets you upload a single object as a set of parts. You can upload these object parts independently and in any order. If transmission of any part fails, you can retransmit that part without affecting other parts. After all parts of your object are uploaded, Amazon S3 assembles the parts and creates the object.

For more information on Amazon S3 multipart uploads, go to Uploading Objects Using Multipart Upload in the Amazon Simple Storage Service Developer Guide.

The Amazon EMR configuration parameters for multipart upload are described in the following table.

Configuration Parameter Name Default Value Description
fs.[s3|s3n].multipart.uploads.enabled True A boolean type that indicates whether to enable multipart uploads.
fs.s3n.ssl.enabled True A boolean type that indicates whether to use http or https.
fs.s3.buckets.create.enabled True This setting automatically creates a bucket if it doesn't exist. Setting to False will cause an exception on CreateBucket operations for that case.

You modify the configuration parameters for multipart uploads using a bootstrap action.

Disable Multipart Upload Using the Amazon EMR Console

This procedure explains how to disable multipart upload using the Amazon EMR console.

To disable multipart uploads with a bootstrap action using the console

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

  2. Choose Create cluster.

  3. Choose Go to advanced options.

  4. Choose Edit Software Settings and enter the following configuration: classification=core-site,properties=[fs.s3.multipart.uploads.enabled=false]

  5. Proceed with creating the cluster as described in Plan and Configure Clusters.

Disable Multipart Upload Using the AWS CLI

This procedure explains how to disable multipart upload using the AWS CLI. To disable multipart upload, type the create-cluster command with the --bootstrap-action parameter.

To disable multipart upload using the AWS CLI

  1. Create a file, myConfig.json, with the following contents:

    [ { "Classification": "core-site", "Properties": { "fs.s3n.multipart.uploads.enabled": "false" } } ]
  2. Type the following command and replace myKey with the name of your EC2 key pair.

    aws emr create-cluster --name "Test cluster" --release-label emr-4.0.0 --applications Name=Hive Name=Pig --use-default-roles --ec2-attributes KeyName=myKey --instance-type m3.xlarge --instance-count 3 --configurations file://./myConfig.json

Disable Multipart Upload Using the API

For information on using Amazon S3 multipart uploads programmatically, go to Using the AWS SDK for Java for Multipart Upload in the Amazon Simple Storage Service Developer Guide.

For more information about the AWS SDK for Java, go to the AWS SDK for Java detail page.