This option is used together with BUCKET_STORAGE_MULTIPLE_ENDPOINTS to allow users to configure buckets in multiple bucket services, for instance to migrate from AWS bucket storage to a local S3 service.

When BUCKET_STORAGE_MULTIPLE_ENDPOINTS is true, each bucket in global can have a separate endpoint configuration, which is defined in this S3_STORAGE_ENDPOINT_BASE variable (e.g., http://my-own-s3:8080).

This allows an existing cluster running against AWS S3 to begin uploading segments to an on-prem S3 by switching the endpoint base, while still keeping access to existing segments in AWS.

See BUCKET_STORAGE_MULTIPLE_ENDPOINTS and S3_STORAGE_ACCESSKEY for more information.