In order to demonstrate Stackdriver with GKE, we will create one namespace on Kubernetes, then launch a sample Pod to see some logs on the Stackdriver, as shown in the following steps:

1. Create the chap9 namespace:

$ kubectl create namespace chap9
namespace "chap9" created

2. Prepare a sample application Pod:

$ cat myapp.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: myapp
spec:
  containers:
  - image: busybox
    name: application
    args:
      - /bin/sh
      - -c
      - >
        while true; do
        echo "$(date) INFO hello";
        sleep 1;
        done

3. Create the Pod on the chap9 namespace:

$ kubectl create -f myapp.yaml --namespace=chap9
pod "myapp" created

4. Access the GCP Web Console and navigate to Logging | Logs.
5. Select Audited Resources | GKE Container | Your GKE cluster name (ex: my-gke) | chap9 namespace:

6. As an alternative way of accessing the chap9 namespace log, you can select an advanced filter. Then, type the following criteria to the text field and click the Submit Filter button:

resource.type="container" 
resource.labels.cluster_name="<Your GKE name>"
resource.labels.namespace_id="chap9"

7. Now, you can see the myapp log on Stackdriver: