helm repo add grafana https://grafana.github.io/helm-charts
helm pull grafana/grafana-agent-operator                                        # grafana-agent-operator-0.2.8.tgz

helm show values ./grafana-agent-operator-0.2.8.tgz > grafana-agent-operator-0.2.8.helm-values.yaml
vim grafana-agent-operator-0.2.8.helm-values.yaml
...（1）nameOverride: "grafana-agent"
...（2）fullnameOverride: "grafana-agent"
...（3）kubeletService.namespace: observing-client

helm install --namespace=observing-client --create-namespace                   \
     grafana-agent                                                             \
    ./grafana-agent-operator-0.2.8.tgz -f grafana-agent-operator-0.2.8.helm-values.yaml