Repository Settings

The s3 repository type supports a number of settings to customize how data is stored in S3. These can be specified when creating the repository. For example:

PUT _snapshot/my_s3_repository
{
  "type": "s3",
  "settings": {
    "bucket": "my_bucket_name",
    "another_setting": "setting_value"
  }
}

The following settings are supported:

bucket
The name of the bucket to be used for snapshots. (Mandatory)
client
The name of the S3 client to use to connect to S3. Defaults to default.
base_path
Specifies the path within bucket to repository data. Defaults to value of repositories.s3.base_path or to root directory if not set. Previously, the base_path could take a leading / (forward slash). However, this has been deprecated and setting the base_path now should omit the leading /.
chunk_size
Big files can be broken down into chunks during snapshotting if needed. Specify the chunk size as a value and unit, for example: 1GB, 10MB, 5KB, 500B. Defaults to 1GB.
compress
When set to true metadata files are stored in compressed format. This setting doesn’t affect index files that are already compressed by default. Defaults to false.
max_restore_bytes_per_sec
Throttles per node restore rate. Defaults to 40mb per second.
max_snapshot_bytes_per_sec
Throttles per node snapshot rate. Defaults to 40mb per second.
readonly
Makes repository read-only. Defaults to false.
server_side_encryption
When set to true files are encrypted on server side using AES256 algorithm. Defaults to false.
buffer_size
Minimum threshold below which the chunk is uploaded using a single request. Beyond this threshold, the S3 repository will use the AWS Multipart Upload API to split the chunk into several parts, each of buffer_size length, and to upload each part in its own request. Note that setting a buffer size lower than 5mb is not allowed since it will prevent the use of the Multipart API and may result in upload errors. It is also not possible to set a buffer size greater than 5gb as it is the maximum upload size allowed by S3. Defaults to the minimum between 100mb and 5% of the heap size.
canned_acl
The S3 repository supports all S3 canned ACLs : private, public-read, public-read-write, authenticated-read, log-delivery-write, bucket-owner-read, bucket-owner-full-control. Defaults to private. You could specify a canned ACL using the canned_acl setting. When the S3 repository creates buckets and objects, it adds the canned ACL into the buckets and objects.
storage_class
Sets the S3 storage class for objects stored in the snapshot repository. Values may be standard, reduced_redundancy, standard_ia and intelligent_tiering. Defaults to standard. Changing this setting on an existing repository only affects the storage class for newly created objects, resulting in a mixed usage of storage classes. Additionally, S3 Lifecycle Policies can be used to manage the storage class of existing objects. Due to the extra complexity with the Glacier class lifecycle, it is not currently supported by the plugin. For more information about the different classes, see AWS Storage Classes Guide

The option of defining client settings in the repository settings as documented below is considered deprecated, and will be removed in a future version.

In addition to the above settings, you may also specify all non-secure client settings in the repository settings. In this case, the client settings found in the repository settings will be merged with those of the named client used by the repository. Conflicts between client and repository settings are resolved by the repository settings taking precedence over client settings.

For example:

PUT _snapshot/my_s3_repository
{
  "type": "s3",
  "settings": {
    "client": "my_client_name",
    "bucket": "my_bucket_name",
    "endpoint": "my.s3.endpoint"
  }
}

This sets up a repository that uses all client settings from the client my_client_name except for the endpoint that is overridden to my.s3.endpoint by the repository settings.

Recommended S3 Permissions

In order to restrict the Elasticsearch snapshot process to the minimum required resources, we recommend using Amazon IAM in conjunction with pre-existing S3 buckets. Here is an example policy which will allow the snapshot access to an S3 bucket named "snaps.example.com". This may be configured through the AWS IAM console, by creating a Custom Policy, and using a Policy Document similar to this (changing snaps.example.com to your bucket name).

{
  "Statement": [
    {
      "Action": [
        "s3:ListBucket",
        "s3:GetBucketLocation",
        "s3:ListBucketMultipartUploads",
        "s3:ListBucketVersions"
      ],
      "Effect": "Allow",
      "Resource": [
        "arn:aws:s3:::snaps.example.com"
      ]
    },
    {
      "Action": [
        "s3:GetObject",
        "s3:PutObject",
        "s3:DeleteObject",
        "s3:AbortMultipartUpload",
        "s3:ListMultipartUploadParts"
      ],
      "Effect": "Allow",
      "Resource": [
        "arn:aws:s3:::snaps.example.com/*"
      ]
    }
  ],
  "Version": "2012-10-17"
}

You may further restrict the permissions by specifying a prefix within the bucket, in this example, named "foo".

{
  "Statement": [
    {
      "Action": [
        "s3:ListBucket",
        "s3:GetBucketLocation",
        "s3:ListBucketMultipartUploads",
        "s3:ListBucketVersions"
      ],
      "Condition": {
        "StringLike": {
          "s3:prefix": [
            "foo/*"
          ]
        }
      },
      "Effect": "Allow",
      "Resource": [
        "arn:aws:s3:::snaps.example.com"
      ]
    },
    {
      "Action": [
        "s3:GetObject",
        "s3:PutObject",
        "s3:DeleteObject",
        "s3:AbortMultipartUpload",
        "s3:ListMultipartUploadParts"
      ],
      "Effect": "Allow",
      "Resource": [
        "arn:aws:s3:::snaps.example.com/foo/*"
      ]
    }
  ],
  "Version": "2012-10-17"
}

The bucket needs to exist to register a repository for snapshots. If you did not create the bucket then the repository registration will fail.

AWS VPC Bandwidth Settings

AWS instances resolve S3 endpoints to a public IP. If the Elasticsearch instances reside in a private subnet in an AWS VPC then all traffic to S3 will go through that VPC’s NAT instance. If your VPC’s NAT instance is a smaller instance size (e.g. a t1.micro) or is handling a high volume of network traffic your bandwidth to S3 may be limited by that NAT instance’s networking bandwidth limitations.

Instances residing in a public subnet in an AWS VPC will connect to S3 via the VPC’s internet gateway and not be bandwidth limited by the VPC’s NAT instance.