Docker Registry v2.2 This Docker Registry release brings a new storage driver implementation to the Docker Registry along with bug fixes, documentation enhancements and logging improvements. What’s new? Google Cloud Storage Driver The Registry now supports Google's reliable and fast network and storage infrastructure for layer and manifest storage. Read-only mode Enables a Registry to serve only read requests, useful to maintain read availability during unsafe administrative tasks. Configurable hostname support Allows the specification of an externally-reachable URL for the Registry. Improved handling of environmental variables Enables environment variables to be specified which are not part of the configuration file. Configurable file-existence and HTTP health checks Allows administrators to easily disable a registry temporarily by placing a file on the filesystem. Additionally a registry can be configured to check the health of other services, such as notification endpoints. Enable configurable HTTP headers to be set in responses This feature is usable for Registry administrators to set response headers for various uses cases including increased security. Redirect Support in the Swift Driver The Swift storage driver now supports generating download URLs in line with other cloud storage drivers. Gotchas In order to support valid hostnames as name components, supporting repeated dash was added. Additionally double underscore is now allowed as a separator to loosen the restriction for previously supported names.