Okera provides a catalog for what we call technical metadata. This is the information required to access the data sets (schemas, location, access policies). For some users, this is sufficient. For others, we've seen them build a catalog that is designed to more specifically model their business objects. In this case, the system would work with the Okera catalog. The Okera catalog could contain the lower level information but the customer's catalog would contain higher level information associated with the customer's business processes.
To be explicit, customers that are used to running Hive Metastore or Sentry Store do not need to do so anymore.
For more information about the Okera catalog service, refer to the documentation here.