To get a MongoDB prompt inside your new cluster you can run:

  ADMIN_USER=$(kubectl -n {{ .Release.Namespace }} get secrets {{ include "psmdb-database.fullname" . }}-secrets -o jsonpath="{.data.MONGODB_USER_ADMIN_USER}" | base64 --decode)
  ADMIN_PASSWORD=$(kubectl -n {{ .Release.Namespace }} get secrets {{ include "psmdb-database.fullname" . }}-secrets -o jsonpath="{.data.MONGODB_USER_ADMIN_PASSWORD}" | base64 --decode)

  $ kubectl run -i --rm --tty percona-client --image=percona/percona-server-mongodb:4.0 --restart=Never \
  -- mongo "mongodb+srv://${ADMIN_USER}:${ADMIN_PASSWORD}@{{ include "psmdb-database.fullname" . }}-{{ .Values.replset.name }}.psmdb.svc.cluster.local/admin?replicaSet=rs0&ssl=false"