Client Settings

The client that you use to connect to S3 has a number of settings available. The settings have the form s3.client.CLIENT_NAME.SETTING_NAME. By default, s3 repositories use a client named default, but this can be modified using the repository setting client. For example:

PUT _snapshot/my_s3_repository
{
  "type": "s3",
  "settings": {
    "bucket": "my-bucket",
    "client": "my-alternate-client"
  }
}

Most client settings can be added to the elasticsearch.yml configuration file with the exception of the secure settings, which you add to the Elasticsearch keystore. For more information about creating and updating the Elasticsearch keystore, see Secure settings.

For example, if you want to use specific credentials to access S3 then run the following commands to add these credentials to the keystore:

bin/elasticsearch-keystore add s3.client.default.access_key
bin/elasticsearch-keystore add s3.client.default.secret_key
# a session token is optional so the following command may not be needed
bin/elasticsearch-keystore add s3.client.default.session_token

If instead you want to use the instance role or container role to access S3 then you should leave these settings unset. You can switch from using specific credentials back to the default of using the instance role or container role by removing these settings from the keystore as follows:

bin/elasticsearch-keystore remove s3.client.default.access_key
bin/elasticsearch-keystore remove s3.client.default.secret_key
# a session token is optional so the following command may not be needed
bin/elasticsearch-keystore remove s3.client.default.session_token

All client secure settings of this plugin are reloadable. After you reload the settings, the internal s3 clients, used to transfer the snapshot contents, will utilize the latest settings from the keystore. Any existing s3 repositories, as well as any newly created ones, will pick up the new values stored in the keystore.

The following list contains the available client settings. Those that must be stored in the keystore are marked as "secure" and are reloadable; the other settings belong in the elasticsearch.yml file.

There are a number of storage systems that provide an S3-compatible API, and the repository-s3 plugin allows you to use these systems in place of AWS S3. To do so, you should set the s3.client.CLIENT_NAME.endpoint setting to the system’s endpoint. This setting accepts IP addresses and hostnames and may include a port. For example, the endpoint may be 172.17.0.2 or 172.17.0.2:9000. You may also need to set s3.client.CLIENT_NAME.protocol to http if the endpoint does not support HTTPS.

Minio is an example of a storage system that provides an S3-compatible API. The repository-s3 plugin allows Elasticsearch to work with Minio-backed repositories as well as repositories stored on AWS S3. Other S3-compatible storage systems may also work with Elasticsearch, but these are not covered by the Elasticsearch test suite.

Note that some storage systems claim to be S3-compatible without correctly supporting the full S3 API. The repository-s3 plugin requires full compatibility with S3. In particular it must support the same set of API endpoints, return the same errors in case of failures, and offer a consistency model no weaker than S3’s when accessed concurrently by multiple nodes. Incompatible error codes and consistency models may be particularly hard to track down since errors and consistency failures are usually rare and hard to reproduce.

You can perform some basic checks of the suitability of your storage system using the repository analysis API. If this API does not complete successfully, or indicates poor performance, then your storage system is not fully compatible with AWS S3 and therefore unsuitable for use as a snapshot repository. You will need to work with the supplier of your storage system to address any incompatibilities you encounter.