The managed HBase instances are automatically configured to export Prometheus metrics. See operators:monitoring.adoc for more details.
Starting with HBase 2.6 the URL for Prometheus metrics has changed.
This is because HBase offers now a built-in endpoint for this purpose.
This endpoint is available from the UI service.
For example, in the case of the master service, the URL is http://<master-service>:16010/prometheus.