S3 storage driver

Estimated reading time: 6 minutes

An implementation of the storagedriver.StorageDriver interface which uses Amazon S3 or S3 compatible services for object storage.


Parameter Required Description
accesskey yes Your AWS Access Key.
secretkey yes Your AWS Secret Key.
region yes The AWS region in which your bucket exists. For the moment, the Go AWS library in use does not use the newer DNS based bucket routing.
regionendpoint no Endpoint for S3 compatible storage services (Minio, etc)
bucket yes The bucket name in which you want to store the registry's data.
encrypt no Specifies whether the registry stores the image in encrypted format or not. A boolean value. The default is false.
keyid no Optional KMS key ID to use for encryption (encrypt must be true, or this parameter will be ignored). The default is none.
secure no Indicates whether to use HTTPS instead of HTTP. A boolean value. The default is true.
v4auth no Indicates whether the registry uses Version 4 of AWS's authentication. By default, this is true.
chunksize no The S3 API requires multipart upload chunks to be at least 5MB. This value should be a number that is larger than 5*1024*1024.
rootdirectory no This is a prefix that will be applied to all S3 keys to allow you to segment data in your bucket if necessary.
storageclass no The S3 storage class applied to each registry file. The default value is STANDARD.

accesskey: Your aws access key.

secretkey: Your aws secret key.

Note You can provide empty strings for your access and secret keys if you plan on running the driver on an ec2 instance and will handle authentication with the instance’s credentials.

region: The name of the aws region in which you would like to store objects (for example us-east-1). For a list of regions, you can look at http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-regions-availability-zones.html

regionendpoint: (optional) Endpoint URL for S3 compatible APIs. This should not be provided when using Amazon S3.

bucket: The name of your S3 bucket where you wish to store objects. The bucket must exist prior to the driver initialization.

encrypt: (optional) Whether you would like your data encrypted on the server side (defaults to false if not specified).

keyid: (optional) Whether you would like your data encrypted with this KMS key ID (defaults to none if not specified, will be ignored if encrypt is not true).

secure: (optional) Whether you would like to transfer data to the bucket over ssl or not. Defaults to true (meaning transferring over ssl) if not specified. Note that while setting this to false will improve performance, it is not recommended due to security concerns.

v4auth: (optional) Whether you would like to use aws signature version 4 with your requests. This defaults to false if not specified (note that the eu-central-1 region does not work with version 2 signatures, so the driver will error out if initialized with this region and v4auth set to false)

chunksize: (optional) The default part size for multipart uploads (performed by WriteStream) to S3. The default is 10 MB. Keep in mind that the minimum part size for S3 is 5MB. Depending on the speed of your connection to S3, a larger chunk size may result in better performance; faster connections will benefit from larger chunk sizes.

rootdirectory: (optional) The root directory tree in which all registry files will be stored. Defaults to the empty string (bucket root).

storageclass: (optional) The storage class applied to each registry file. Defaults to STANDARD. Valid options are STANDARD and REDUCED_REDUNDANCY.

S3 permission scopes

The following AWS policy is required by the registry for push and pull. Make sure to replace S3_BUCKET_NAME with the name of your bucket.

  "Version": "2012-10-17",
  "Statement": [
      "Effect": "Allow",
      "Action": [
      "Resource": "arn:aws:s3:::S3_BUCKET_NAME"
      "Effect": "Allow",
      "Action": [
      "Resource": "arn:aws:s3:::S3_BUCKET_NAME/*"

See the S3 policy documentation for more details.

CloudFront as Middleware with S3 backend

Use Case

Adding CloudFront as a middleware for your S3 backed registry can dramatically improve pull times. Your registry will have the ability to retrieve your images from edge servers, rather than the geographically limited location of your S3 bucket. The farther your registry is from your bucket, the more improvements you will see. See Amazon CloudFront.

Configuring CloudFront for Distribution

If you are unfamiliar with creating a CloudFront distribution, see Getting Started with Cloudfront.

Defaults can be kept in most areas except:


The CloudFront distribution must be created such that the Origin Path is set to the directory level of the root “docker” key in S3. If your registry exists on the root of the bucket, this path should be left blank.


  • Viewer Protocol Policy: HTTPS Only
  • Cached HTTP Methods: OPTIONS (checked)
  • Restrict Viewer Access (Use Signed URLs or Signed Cookies): Yes
    • Trusted Signers: Self (Can add other accounts as long as you have access to CloudFront Key Pairs for those additional accounts)

Registry configuration

Here the middleware option is used. It is still important to keep the storage option as CloudFront will only handle pull actions; push actions are still directly written to S3.

The following example shows what you will need at minimum:

    region: us-east-1
    bucket: docker.myregistry.com
    - name: cloudfront
        baseurl: https://abcdefghijklmn.cloudfront.net/
        privatekey: /etc/docker/cloudfront/pk-ABCEDFGHIJKLMNOPQRST.pem

CloudFront Key-Pair

A CloudFront key-pair is required for all AWS accounts needing access to your CloudFront distribution. For information, please see Creating CloudFront Key Pairs.

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