A significant new capability has been added to Dataproc Metastore: Lakehouse proxy routing. This enables phased migrations where namespaces can be moved from Dataproc Metastore to a Lakehouse Iceberg REST Catalog in batches. The metastore service can now operate in a PROXY state, forwarding requests for migrated namespaces to the Lakehouse catalog while serving unmigrated ones locally.
This update introduces the new LakehouseProxyConfig schema and integrates it into the Service resource via the lakehouseProxyConfig property. Developers should note that the catalog and namespaces properties within LakehouseProxyConfig, as well as the lakehouseProxyConfig property itself within the Service schema, are now explicitly marked as readOnly. This is a breaking change if any existing integrations or preview code were attempting to set or modify these properties; such operations will now fail. These fields are intended to reflect the current state of the proxy configuration, not to be directly configured via the API.
