MariaDBoperator not acting on custom resource

Question

I have a k8s clusters, with OLM and the MariaDB Operator installed (according the steps on the operator install page):

kubectl create -f https://operatorhub.io/install/mariadb-operator.yaml

When I list the ClusterServiceVersions in each namespace with

kubectl get csv -A

the result shows a phase 'Succeeded' for each namespace. Now when I create this CustomResource in a arbitrary namespace nothing happens (no events in k8s or whatsoever):

apiVersion: mariadb.mmontes.io/v1alpha1
kind: MariaDB
metadata:
  name: mariadb
spec:
  rootPasswordSecretKeyRef:
    name: mariadb
    key: root-password

  image:
    repository: mariadb
    tag: "10.11.3"
    pullPolicy: IfNotPresent

  port: 3306

  volumeClaimTemplate:
    resources:
      requests:
        storage: 100Mi
    accessModes:
      - ReadWriteOnce

What am I missing?