I am trying to monitor my Vespa cluster (with the help of the Prometheus exporter), but I can't find the right metrics to observe to know the space my index is taking, nor the space my replicas are taking. And I would also like to find a simple way of visualizing the number of documents that are indexed in my cluster, but I can't find a simple way of doing that. I have found the vespa_container_documents_total
metric, but its value if always zero. The only way I've found to get its real value is to perform a search request on the cluster, then, this metric is populated. But only for a few time (like one minute), and then it gets back to zero.
So, is there a way to simply monitor those two metrics ?