Enable application logging and monitoring

This page shows how to configure a cluster for GKE on Bare Metal so that custom logs and metrics from user applications are sent to Cloud Logging and Cloud Monitoring.

Enabling Logging and Monitoring for user applications

To enable Logging and Monitoring for your applications, use the spec.clusterOperations.enableApplication field in the cluster configuration file.

  1. Update the cluster configuration file to set enableApplication to true:

    apiVersion: v1
kind: Namespace
metadata:
  name: cluster-user-basic
---
apiVersion: baremetal.cluster.gke.io/v1
kind: Cluster
metadata:
  name: user-basic
  namespace: cluster-user-basic
spec:
  type: user
  ...
  clusterOperations:
    projectID: project-fleet
    location: us-central1
    enableApplication: true
    ...

  2. Use bmctl update to apply your changes:

    bmctl update cluster -c CLUSTER_NAME --admin-kubeconfig=ADMIN_KUBECONFIG

    Replace the following:

    • CLUSTER_NAME: the name of the cluster to upgrade.
    • ADMIN_KUBECONFIG: the path to the admin cluster kubeconfig file.

Annotate workloads

To enable the collection of custom metrics from an application, add the prometheus.io/scrape: "true" annotation to the application's Service or Deployment manifest.

Run an example application

In this section, you create an application that writes custom logs and exposes a custom metric.

  1. Save the following Service and Deployment manifests to a file named my-app.yaml. Notice that the Service has the annotation prometheus.io/scrape: "true":

    kind: Service
apiVersion: v1
metadata:
  name: "monitoring-example"
  namespace: "default"
  annotations:
    prometheus.io/scrape: "true"
spec:
  selector:
    app: "monitoring-example"
  ports:
    - name: http
      port: 9090
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: "monitoring-example"
  namespace: "default"
  labels:
    app: "monitoring-example"
spec:
  replicas: 1
  selector:
    matchLabels:
      app: "monitoring-example"
  template:
    metadata:
      labels:
        app: "monitoring-example"
    spec:
      containers:
      - image: gcr.io/google-samples/prometheus-dummy-exporter:latest
        name: prometheus-example-exporter
        imagePullPolicy: Always
        command:
        - /bin/sh
        - -c
        - ./prometheus-dummy-exporter --metric-name=example_monitoring_up --metric-value=1 --port=9090
        resources:
          requests:
            cpu: 100m

  2. Create the Deployment and the Service:

    kubectl --kubeconfig CLUSTER_KUBECONFIG apply -f my-app.yaml

View application logs

Console

  1. Go to the Logs explorer in the Google Cloud console.

    Go to the Logs explorer

  2. Click Resource. Under ALL_RESOURCE_TYPES, select Kubernetes Container.

  3. Under CLUSTER_NAME, select the name of your user cluster.

  4. Under NAMESPACE_NAME, select default.

  5. Click Add and then click Run Query.

  6. Under Query results, you can see log entries from the monitoring-example Deployment. For example:

    {
  "textPayload": "2020/11/14 01:24:24 Starting to listen on :9090\n",
  "insertId": "1oa4vhg3qfxidt",
  "resource": {
    "type": "k8s_container",
    "labels": {
      "pod_name": "monitoring-example-7685d96496-xqfsf",
      "cluster_name": ...,
      "namespace_name": "default",
      "project_id": ...,
      "location": "us-west1",
      "container_name": "prometheus-example-exporter"
    }
  },
  "timestamp": "2020-11-14T01:24:24.358600252Z",
  "labels": {
    "k8s-pod/pod-template-hash": "7685d96496",
    "k8s-pod/app": "monitoring-example"
  },
  "logName": "projects/.../logs/stdout",
  "receiveTimestamp": "2020-11-14T01:24:39.562864735Z"
}

gcloud

  1. Run this command:

    gcloud logging read 'resource.labels.project_id="PROJECT_ID" AND \
    resource.type="k8s_container" AND resource.labels.namespace_name="default"'

    Replace PROJECT_ID with the ID of your project.

  2. In the output, you can see log entries from the monitoring-example Deployment. For example:

    insertId: 1oa4vhg3qfxidt
labels:
  k8s-pod/app: monitoring-example
  k8s- pod/pod-template-hash: 7685d96496
logName: projects/.../logs/stdout
receiveTimestamp: '2020-11-14T01:24:39.562864735Z'
resource:
  labels:
    cluster_name: ...
    container_name: prometheus-example-exporter
    location: us-west1
    namespace_name: default
    pod_name: monitoring-example-7685d96496-xqfsf
    project_id: ...
  type: k8s_container
textPayload: |
  2020/11/14 01:24:24 Starting to listen on :9090
timestamp: '2020-11-14T01:24:24.358600252Z'

View application metrics in the Google Cloud console

Your example application exposes a custom metric named example_monitoring_up. You can view the values of that metric in the Google Cloud console.

  1. Go to the Metrics explorer in the Google Cloud console.

    Go to the Metrics explorer

  2. For Resource type, select Kubernetes Pod.

  3. For metric, select external/prometheus/example_monitoring_up.

  4. In the chart, you can see that example_monitoring_up has a repeated value of 1.