MongoDB Exporter missing metrics, Engine is unavailable

Hi.
We are using mongodb-exporter and we’re having issues getting some metrics. Both exporter and MongoDB cluster (sharded, 19 replicasets) are deployed on a Kubernetes cluster. Exporter is only logging such errors: “cannot retrieve engine type: Engine is unavailable”.
Also metrics per certain replicasets are missing, eg. mongodb_mongod_replset_my_state{set=“rs0”} . Moreover there’s a mismatch: mongodb_mongos_sharding_databases_total{type=“partitioned”}) returns 0 DBs while mongodb_mongos_sharding_shards_total returns 19 shards.
One observation - when using certain replicaset service uri as mongodb_uri parameter in exporter, the mongodb_mongod_replset_my_state metric works for that particular replicaset (however most of the rest of metrics not).

So, I have two questions:

  1. Are we missing something here either with the exporter or mongodb configuration etc. ?
  2. I saw that there were some changes in exporter earlier this year (related to shards) which weren’t released yet. When we can expect a new version of the exporter, is there chance it may fix our issue ? (I believe here’s a related ticket: [PMM-12350] - Percona JIRA )

Exporter is configured in a such way:

  • mongodb_uri is a URI to a mongos service
  • extra args: --discovering-mode --collect-all --compatible-mode --mongodb.direct-connect

Diagnostic data and profile metrics gathering are enabled. Also the monitoring user has required privileges.
Versions:
Exporter: 0.40.0
MongoDB: 7.0.8-5 (metrics were missing also on 6.x)

Thank you in advance, Krzysztof