Setting Object Ownership when you create a bucket - Amazon Simple Storage Service
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Setting Object Ownership when you create a bucket

When you create a bucket, you can configure S3 Object Ownership. To set Object Ownership for an existing bucket, see Setting Object Ownership on an existing bucket.

S3 Object Ownership is an Amazon S3 bucket-level setting that you can use to disable access control lists (ACLs) and take ownership of every object in your bucket, simplifying access management for data stored in Amazon S3. By default, S3 Object Ownership is set to the Bucket owner enforced setting, and ACLs are disabled for new buckets. With ACLs disabled, the bucket owner owns every object in the bucket and manages access to data exclusively by using access-management policies. We recommend that you keep ACLs disabled, except in unusual circumstances where you must control access for each object individually.

Object Ownership has three settings that you can use to control ownership of objects uploaded to your bucket and to disable or enable ACLs:

ACLs disabled

  • Bucket owner enforced (default) – ACLs are disabled, and the bucket owner automatically owns and has full control over every object in the bucket. ACLs no longer affect permissions to data in the S3 bucket. The bucket uses policies to define access control.

ACLs enabled

  • Bucket owner preferred – The bucket owner owns and has full control over new objects that other accounts write to the bucket with the bucket-owner-full-control canned ACL.

  • Object writer – The Amazon Web Services account that uploads an object owns the object, has full control over it, and can grant other users access to it through ACLs.

Permissions: To apply the Bucket owner enforced setting or the Bucket owner preferred setting, you must have the following permissions: s3:CreateBucket and s3:PutBucketOwnershipControls. No additional permissions are needed when creating a bucket with the Object writer setting applied. For more information about Amazon S3 permissions, see Actions, resources, and condition keys for Amazon S3 in the Service Authorization Reference.

For more information about the permissions to S3 API operations by S3 resource types, see Required permissions for Amazon S3 API operations.

Important

A majority of modern use cases in Amazon S3 no longer require the use of ACLs, and we recommend that you disable ACLs except in unusual circumstances where you need to control access for each object individually. With Object Ownership, you can disable ACLs and rely on policies for access control. When you disable ACLs, you can easily maintain a bucket with objects uploaded by different Amazon accounts. You, as the bucket owner, own all the objects in the bucket and can manage access to them using policies.

  1. Sign in to the Amazon Web Services Management Console and open the Amazon S3 console at https://console.amazonaws.cn/s3/.

  2. In the navigation bar on the top of the page, choose the name of the currently displayed Amazon Web Services Region. Next, choose the Region in which you want to create a bucket.

    Note

    • After you create a bucket, you can't change its Region.

    • To minimize latency and costs and address regulatory requirements, choose a Region close to you. Objects stored in a Region never leave that Region unless you explicitly transfer them to another Region. For a list of Amazon S3 Amazon Web Services Regions, see Amazon Web Services service endpoints in the Amazon Web Services General Reference.

  3. In the left navigation pane, choose General purpose buckets.

  4. Choose Create bucket. The Create bucket page opens.

  5. For Bucket name, enter a name for your bucket.

    The bucket name must:

    • Be unique within a partition. A partition is a grouping of Regions. Amazon currently has three partitions: aws (commercial Regions), aws-cn (China Regions), and aws-us-gov (Amazon GovCloud (US) Regions).

    • Be between 3 and 63 characters long.

    • Consist only of lowercase letters, numbers, periods (.), and hyphens (-). For best compatibility, we recommend that you avoid using periods (.) in bucket names, except for buckets that are used only for static website hosting.

    • Begin and end with a letter or number.

    • For a complete list of bucket-naming rules, see General purpose bucket naming rules.

    Important

    • After you create the bucket, you can't change its name.

    • Don't include sensitive information in the bucket name. The bucket name is visible in the URLs that point to the objects in the bucket.

  6. (Optional) Under General configuration, you can choose to copy an existing bucket's settings to your new bucket. If you don't want to copy the settings of an existing bucket, skip to the next step.

    Note

    This option:

    • Isn't available in the Amazon CLI and is only available in the Amazon S3 console

    • Doesn't copy the bucket policy from the existing bucket to the new bucket

    To copy an existing bucket's settings, under Copy settings from existing bucket, select Choose bucket. The Choose bucket window opens. Find the bucket with the settings that you want to copy, and select Choose bucket. The Choose bucket window closes, and the Create bucket window reopens.

    Under Copy settings from existing bucket, you now see the name of the bucket that you selected. The settings of your new bucket now match the settings of the bucket that you selected. If you want to remove the copied settings, choose Restore defaults. Review the remaining bucket settings on the Create bucket page. If you don't want to make any changes, you can skip to the final step.

  7. Under Object Ownership, to disable or enable ACLs and control ownership of objects uploaded in your bucket, choose one of the following settings:

    ACLs disabled

    • Bucket owner enforced (default) – ACLs are disabled, and the bucket owner automatically owns and has full control over every object in the general purpose bucket. ACLs no longer affect access permissions to data in the S3 general purpose bucket. The bucket uses policies exclusively to define access control.

      By default, ACLs are disabled. A majority of modern use cases in Amazon S3 no longer require the use of ACLs. We recommend that you keep ACLs disabled, except in unusual circumstances where you must control access for each object individually. For more information, see Controlling ownership of objects and disabling ACLs for your bucket.

    ACLs enabled

    • Bucket owner preferred – The bucket owner owns and has full control over new objects that other accounts write to the bucket with the bucket-owner-full-control canned ACL.

      If you apply the Bucket owner preferred setting, to require all Amazon S3 uploads to include the bucket-owner-full-control canned ACL, you can add a bucket policy that allows only object uploads that use this ACL.

    • Object writer – The Amazon Web Services account that uploads an object owns the object, has full control over it, and can grant other users access to it through ACLs.

    Note

    The default setting is Bucket owner enforced. To apply the default setting and keep ACLs disabled, only the s3:CreateBucket permission is needed. To enable ACLs, you must have the s3:PutBucketOwnershipControls permission.

  8. Under Block Public Access settings for this bucket, choose the Block Public Access settings that you want to apply to the bucket.

    By default, all four Block Public Access settings are enabled. We recommend that you keep all settings enabled, unless you know that you need to turn off one or more of them for your specific use case. For more information about blocking public access, see Blocking public access to your Amazon S3 storage.

    Note

    To enable all Block Public Access settings, only the s3:CreateBucket permission is required. To turn off any Block Public Access settings, you must have the s3:PutBucketPublicAccessBlock permission.

  9. (Optional) By default, Bucket Versioning is disabled. Versioning is a means of keeping multiple variants of an object in the same bucket. You can use versioning to preserve, retrieve, and restore every version of every object stored in your bucket. With versioning, you can recover more easily from both unintended user actions and application failures. For more information about versioning, see Retaining multiple versions of objects with S3 Versioning.

    To enable versioning on your bucket, choose Enable.

  10. (Optional) Under Tags, you can choose to add tags to your bucket. With Amazon cost allocation, you can use bucket tags to annotate billing for your use of a bucket. A tag is a key-value pair that represents a label that you assign to a bucket. For more information, see Using cost allocation S3 bucket tags.

    To add a bucket tag, enter a Key and optionally a Value and choose Add Tag.

  11. To configure Default encryption, under Encryption type, choose one of the following:

    • Server-side encryption with Amazon S3 managed keys (SSE-S3)

    • Server-side encryption with Amazon Key Management Service keys (SSE-KMS)

    • Dual-layer server-side encryption with Amazon Key Management Service (Amazon KMS) keys (DSSE-KMS)

      Important

      If you use the SSE-KMS or DSSE-KMS option for your default encryption configuration, you are subject to the requests per second (RPS) quota of Amazon KMS. For more information about Amazon KMS quotas and how to request a quota increase, see Quotas in the Amazon Key Management Service Developer Guide.

    Buckets and new objects are encrypted by using server-side encryption with Amazon S3 managed keys (SSE-S3) as the base level of encryption configuration. For more information about default encryption, see Setting default server-side encryption behavior for Amazon S3 buckets. For more information about SSE-S3, see Using server-side encryption with Amazon S3 managed keys (SSE-S3).

    For more information about using server-side encryption to encrypt your data, see Protecting data with encryption.

  12. If you chose Server-side encryption with Amazon S3 managed keys (SSE-S3) or Dual-layer server-side encryption with Amazon Key Management Service (Amazon KMS) keys (DSSE-KMS), do the following:

    1. Under Amazon KMS key, specify your KMS key in one of the following ways:

      • To choose from a list of available KMS keys, choose Choose from your Amazon KMS keys, and choose your KMS key from the list of available keys.

        Both the Amazon managed key (aws/s3) and your customer managed keys appear in this list. For more information about customer managed keys, see Customer keys and Amazon keys in the Amazon Key Management Service Developer Guide.

      • To enter the KMS key ARN, choose Enter Amazon KMS key ARN, and enter your KMS key ARN in the field that appears.

      • To create a new customer managed key in the Amazon KMS console, choose Create a KMS key.

        For more information about creating an Amazon KMS key, see Creating keys in the Amazon Key Management Service Developer Guide.

      Important

      You can use only KMS keys that are available in the same Amazon Web Services Region as the bucket. The Amazon S3 console lists only the first 100 KMS keys in the same Region as the bucket. To use a KMS key that isn't listed, you must enter your KMS key ARN. If you want to use a KMS key that's owned by a different account, you must first have permission to use the key, and then you must enter the KMS key ARN. For more information about cross account permissions for KMS keys, see Creating KMS keys that other accounts can use in the Amazon Key Management Service Developer Guide. For more information about SSE-KMS, see Specifying server-side encryption with Amazon KMS (SSE-KMS). For more information about DSSE-KMS, see Using dual-layer server-side encryption with Amazon KMS keys (DSSE-KMS).

      When you use an Amazon KMS key for server-side encryption in Amazon S3, you must choose a symmetric encryption KMS key. Amazon S3 supports only symmetric encryption KMS keys and not asymmetric KMS keys. For more information, see Identifying symmetric and asymmetric KMS keys in the Amazon Key Management Service Developer Guide.

    2. When you configure your bucket to use default encryption with SSE-KMS, you can also use S3 Bucket Keys. S3 Bucket Keys lower the cost of encryption by decreasing request traffic from Amazon S3 to Amazon KMS. For more information, see Reducing the cost of SSE-KMS with Amazon S3 Bucket Keys. S3 Bucket Keys aren't supported for DSSE-KMS.

      By default, S3 Bucket Keys are enabled in the Amazon S3 console. We recommend leaving S3 Bucket Keys enabled to lower your costs. To disable S3 Bucket Keys for your bucket, under Bucket Key, choose Disable.

  13. (Optional) S3 Object Lock helps protect new objects from being deleted or overwritten. For more information, see Locking objects with Object Lock. If you want to enable S3 Object Lock, do the following:

    1. Choose Advanced settings.

      Important

      Enabling Object Lock automatically enables versioning for the bucket. After you've enabled and successfully created the bucket, you must also configure the Object Lock default retention and legal hold settings on the bucket's Properties tab.

    2. If you want to enable Object Lock, choose Enable, read the warning that appears, and acknowledge it.

    Note

    To create an Object Lock enabled bucket, you must have the following permissions: s3:CreateBucket, s3:PutBucketVersioning, and s3:PutBucketObjectLockConfiguration.

  14. Choose Create bucket.

To set Object Ownership when you create a new bucket, use the create-bucket Amazon CLI command with the --object-ownership parameter.

This example applies the Bucket owner enforced setting for a new bucket using the Amazon CLI:

aws s3api create-bucket --bucket  amzn-s3-demo-bucket --region us-east-1 --object-ownership BucketOwnerEnforced
Important

If you don’t set Object Ownership when you create a bucket by using the Amazon CLI, the default setting will be ObjectWriter (ACLs enabled).

This example sets the Bucket owner enforced setting for a new bucket using the Amazon SDK for Java:

    // Build the ObjectOwnership for CreateBucket
    CreateBucketRequest createBucketRequest = CreateBucketRequest.builder()
            .bucket(bucketName)
            .objectOwnership(ObjectOwnership.BucketOwnerEnforced)
            .build()

     // Send the request to Amazon S3 
     s3client.createBucket(createBucketRequest);

To use the AWS::S3::Bucket Amazon CloudFormation resource to set Object Ownership when you create a new bucket, see OwnershipControls within AWS::S3::Bucket in the Amazon CloudFormation User Guide.

To apply the Bucket owner enforced setting for S3 Object Ownership, use the CreateBucket API operation with the x-amz-object-ownership request header set to BucketOwnerEnforced. For information and examples, see CreateBucket in the Amazon Simple Storage Service API Reference.

Next steps: After you apply the Bucket owner enforced or bucket owner preferred settings for Object Ownership, you can further take the following steps:

  • Bucket owner enforced – Require that all new buckets are created with ACLs disabled by using an IAM or Organizations policy.

  • Bucket owner preferred – Add an S3 bucket policy to require the bucket-owner-full-control canned ACL for all object uploads to your bucket.