Control Plane Reaper not working with different namespaces

[zehweh]

What happened?

After creating a Control Plane Reaper in the operator namespace and setting

spec:
  reaper:
    reaperRef:
      name: reaper
      namespace: k8ssandra-operator

in the K8ssandraCluster (different namespace), I noticed that the reaper doesn't add the cluster to it's config.

Reaper logs show:

INFO   [2025-01-07 15:03:34,355] [dw-29467 - PUT /cluster/testcluster?seedHost=testcluster-seed-service] i.c.r.ClusterResource - PUT addOrUpdateCluster called with: cluster_name = testcluster, seedHost = testcluster-seed-service
INFO   [2025-01-07 15:03:34,671] [dw-29467 - PUT /cluster/testcluster?seedHost=testcluster-seed-service] i.c.m.h.HttpManagementConnectionFactory - Unreachable host: testcluster-seed-service
io.cassandrareaper.ReaperException: Error getting local endpoint

Operator logs show:

2025-01-07T16:00:44.420Z        ERROR   Failed to add cluster to external Reaper        {"controller": "k8ssandracluster",
"controllerGroup": "k8ssandra.io", "controllerKind": "K8ssandraCluster", "K8ssandraCluster": {"name":"testcluster","namespace":"clusternamespace"}, "namespace": "clusternamespace", "name": "testcluster", "reconcileID": "59b12091-8f4d-4137-b8db-4b3a9b4ec9a0", "K8ssandraCluster":
 {"name":"testcluster","namespace":"clusternamespace"}, "CassandraDatacenter": {"name":"dc-testcluster","namespace":"clusternamespace"}, "Reaper": {"name":"testcluster-dc-testcluster-reaper","namespace":"clusternamespace"}, "error": "failed to create cluster testcluster: no cluster testcluster with seed host testcluster-seed-service (HTTP status 400)"}

It can't connect to the service because it is running in a different namespace.

Did you expect to see something different?

I expect the operator to register the cluster with the right service, like: testcluster-seed-service.clusternamespace

How to reproduce it (as minimally and precisely as possible):

Deploy the operator and add a reaperRef to a K8ssandraCluster running in a different namespace.

Environment

• K8ssandra Operator version:

  1.20.3

• Kubernetes version information:

Client Version: v1.28.3
Server Version: v1.28.3

┆Issue is synchronized with this Jira Story by Unito
┆Issue Number: K8OP-303