Not able to remove a shard in MongoDB Server version 8

[enrico-rabeneck]

Report

Not possible to remove a shard in a multi sharded cluster in since MongoDB server version 8.

More about the problem

We have a running test cluster with two shards rs0 and rs1. When updating the cr.yaml without the rs1 configuration the following error is thrown:

2025-03-19T13:27:40.154Z ERROR Reconciler error {"controller": "psmdb-controller", "controllerGroup": "psmdb.percona.com", "controllerKind": "PerconaServerMongoDB", "PerconaServerMongoDB": {"name":"cluster-psmdb-db","namespace":"my-cluster-name"}, "namespace": "my-cluster-name", "name": "cluster-psmdb-db", "reconcileID": "863409b3-0d63-4edc-8fba-8aab8a8014f6", "error": "check remove posibility for rs rs1: failed to list databases for rs rs1: listDatabases: (Unauthorized) You are connecting to a sharded cluster improperly by connecting directly to a shard. Please connect to the cluster via a router (mongos).", "errorVerbose": "(Unauthorized) You are connecting to a sharded cluster improperly by connecting directly to a shard. Please connect to the cluster via a router (mongos).\nlistDatabases\ngithub.com/percona/percona-server-mongodb-operator/pkg/psmdb/mongo.(*mongoClient).ListDBs\n\t/go/src/github.com/percona/percona-server-mongodb-operator/pkg/psmdb/mongo/mongo.go:490\ngithub.com/percona/percona-server-mongodb-operator/pkg/controller/perconaservermongodb. [...]

Expectation:
The shard rs1 is removed.

Steps to reproduce

1. Create a sharded cluster with at least two shards.
2. Remove one shard from the configuration.

Versions

1. Kubernetes: AWS EKS 1.32
2. Operator: 1.19.1
3. Database: percona-server-mongodb:8.0.4-2

Anything else?

Not possible to change system-level users to add the missing privilege directShardOperations