redis_exporter with Google Memorystore for Redis - kubernetes

Question

I have a prometheus instance installed on my gke cluster (operator-prometheus), I would like to scrape metrics from my gcp managed redis instance.
I have the following deployment definition for redis_exporter:
apiVersion: apps/v1
kind: Deployment
metadata:
name: redis-exporter
spec:
selector:
matchLabels:
app: redis-exporter
replicas: 1
template:
metadata:
labels:
app: redis-exporter
annotations:
prometheus.io/port: "9121"
prometheus.io/scrape: "true"
spec:
containers:
- name: redis-exporter
image: oliver006/redis_exporter:latest
ports:
- containerPort: 9121
env:
- name: REDIS_ADDR
value: 'redis://10.xxx.151.xxx:6379'
resources:
limits:
memory: "256Mi"
cpu: "256m"
My service definition:
apiVersion: v1
kind: Service
metadata:
name: redis-external-exporter
namespace: monitoring
annotations:
prometheus.io/scrape: 'true'
prometheus.io/port: "9121"
spec:
ports:
- name: redis-ext
port: 9121
protocol: TCP
targetPort: 9121
selector:
app: redis-exporter
And finally, my ServiceMonitor definition
apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
name: redis-external-exporter
labels:
app: redis-external-exporter
prometheus-instance: clusterwide
spec:
jobLabel: app
selector:
matchLabels:
app: redis-ext
endpoints:
- interval: 30s
port: redis-ext
honorLabels: true
path: /metrics
namespaceSelector:
matchNames:
- monitoring
Am I missing something? If I browse to port 9121 I'm able to see the metrics, it seems its just a problem of connect all the pieces together.
Kindly asking for your help!