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Monitor KubeVault operator with builtin Prometheus

This tutorial will show you how to configure builtin Prometheus scraper to monitor KubeVault operator.

Before You Begin

At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using kind.

To keep Prometheus resources isolated, we are going to use a separate namespace to deploy Prometheus server.

$ kubectl create ns monitoring
namespace/monitoring created

Enable Monitoring in KubeVault operator

Enable Prometheus monitoring using prometheus.io/builtin annotations while install KubeVault operator. To know details about how to enable monitoring see here

Here, we are going to enable monitoring for operator metrics.

Using Helm 3:

$ helm install vault-operator appscode/vault-operator --version v2021.09.27 \
  --namespace kube-system \
  --set monitoring.agent=prometheus.io/builtin \
  --set monitoring.operator=true \
  --set monitoring.prometheus.namespace=monitoring

Using Helm 2:

$ helm install appscode/vault-operator --name vault-operator --version v2021.09.27 \
  --namespace kube-system \
  --set monitoring.agent=prometheus.io/builtin \
  --set monitoring.operator=true \
  --set monitoring.prometheus.namespace=monitoring

Using YAML (with Helm 3):

$ helm template vault-operator appscode/vault-operator --version v2021.09.27 \
  --namespace kube-system \
  --no-hooks \
  --set monitoring.agent=prometheus.io/builtin \
  --set monitoring.operator=true \
  --set monitoring.prometheus.namespace=monitoring | kubectl apply -f -

This will add necessary annotations to vault-operator service. Prometheus server will scrap metrics using those annotations. Let’s check which annotations are added to the service,

$ kubectl get svc vault-operator -n kube-system -o yaml
apiVersion: v1
kind: Service
metadata:
  annotations:
    prometheus.io/path: /metrics
    prometheus.io/port: "8443"
    prometheus.io/scheme: https
    prometheus.io/scrape: "true"
  creationTimestamp: "2018-12-26T06:12:51Z"
  labels:
    app: vault-operator
    chart: vault-operator-v2021.09.27
    heritage: Tiller
    release: vault-operator
  name: vault-operator
  namespace: kube-system
  resourceVersion: "10030"
  selfLink: /api/v1/namespaces/kube-system/services/vault-operator
  uid: 469d2c8f-08d5-11e9-852c-080027857726
spec:
  clusterIP: 10.110.168.15
  ports:
  - name: api
    port: 443
    protocol: TCP
    targetPort: 8443
  selector:
    app: vault-operator
    release: vault-operator
  sessionAffinity: None
  type: ClusterIP
status:
  loadBalancer: {}

Here, prometheus.io/scrape: "true" annotation indicates that Prometheus should scrap metrics for this service.

The following three annotations point to api endpoints which provides operator specific metrics.

prometheus.io/path: /metrics
prometheus.io/port: "8443"
prometheus.io/scheme: https

Now, we are ready to configure our Prometheus server to scrap those metrics.

Deploy Prometheus Server

We have deployed KubeVault operator in kube-system namespace. KubeVault operator exports operator metrics via TLS secured api endpoint. So, Prometheus server need to provide certificate while scraping metrics from this endpoint. KubeVault operator has created a secret named vault-operator-apiserver-cert with this certificate in monitoring namespaces as we have specified that we are going to deploy Prometheus in that namespace through --prometheus-namespace or monitoring.prometheus.namespace flag. We have to mount this secret in Prometheus deployment.

Let’s check vault-operator-apiserver-cert secret has been created in monitoring namespace.

$ kubectl get  secrets -n monitoring -l=app.kubernetes.io/name=vault-operator
NAME                            TYPE                DATA   AGE
vault-operator-apiserver-cert   kubernetes.io/tls   2      107m

Create RBAC

If you are using a RBAC enabled cluster, you have to provide necessary RBAC permissions for Prometheus. Following this, let’s create RBAC stuffs for Prometheus by running:

$ kubectl apply -f https://github.com/appscode/third-party-tools/raw/master/monitoring/prometheus/builtin/artifacts/rbac.yaml
clusterrole.rbac.authorization.k8s.io/prometheus created
serviceaccount/prometheus created
clusterrolebinding.rbac.authorization.k8s.io/prometheus created

YAML for RBAC resources can be found here.

Create ConfigMap

As we are monitoring KubeVault operator, we should follow this to create a ConfigMap. Bellow the YAML of ConfigMap that we are going to create in this tutorial

apiVersion: v1
kind: ConfigMap
metadata:
  name: prometheus-config
  labels:
    name: prometheus-config
  namespace: monitoring
data:
  prometheus.yml: |-
    global:
      scrape_interval: 5s
      evaluation_interval: 5s
    scrape_configs:
    - job_name: 'vault-apiservers'
      honor_labels: true
      kubernetes_sd_configs:
      - role: endpoints
      # Kubernetes apiserver serve metrics on a TLS secure endpoints. so, we have to use "https" scheme
      scheme: https
      # we have to provide certificate to establish tls secure connection
      tls_config:
        ca_file: /etc/prometheus/secret/vault-operator-apiserver-cert/tls.crt
        server_name: vault-operator.kube-system.svc
      #  bearer_token_file is required for authorizating prometheus server to Kubernetes apiserver
      bearer_token_file: /var/run/secrets/kubernetes.io/serviceaccount/token

      relabel_configs:
      - source_labels: [__meta_kubernetes_service_label_app]
        separator: ;
        regex: vault-operator
        replacement: $1
        action: keep
      - source_labels: [__meta_kubernetes_endpoint_address_target_kind, __meta_kubernetes_endpoint_address_target_name]
        separator: ;
        regex: Node;(.*)
        target_label: node
        replacement: ${1}
        action: replace
      - source_labels: [__meta_kubernetes_namespace, __meta_kubernetes_service_name, __meta_kubernetes_endpoint_port_name]
        action: keep
        regex: kube-system;vault-operator;api
      - separator: ;
        regex: (.*)
        target_label: endpoint
        replacement: api
        action: replace
      - source_labels: [__meta_kubernetes_service_name]
        separator: ;
        regex: (.*)
        target_label: job
        replacement: ${1}
        action: replace    

Look at the tls_config field of vault-apiservers job. We have provided certificate file through ca_file field. This certificate comes from vault-operator-apiserver-cert that we are going to mount in Prometheus deployment. Here, server_name is used to verify hostname. In our case, the certificate is valid for hostname server and vault-operator.kube-system.svc.

In relabel_configs section we added <operator_name>.<namespace>.svc:443 as the value of replacement.

Let’s create the ConfigMap we have shown above,

$ kubectl apply -f https://github.com/kubevault/kubevault/raw/v2021.09.27/docs/examples/monitoring/vault-operator/prom-server-conf.yaml
configmap/prometheus-config created

Deploy Prometheus

Now, we are ready to deploy Prometheus server. YAML for the deployment that we are going to create for Prometheus is shown below.

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: prometheus-demo
  name: prometheus
  namespace: monitoring
spec:
  replicas: 1
  selector:
    matchLabels:
      app: prometheus
  template:
    metadata:
      labels:
        app: prometheus
    spec:
      containers:
      - args:
        - --config.file=/etc/prometheus/prometheus.yml
        - --storage.tsdb.path=/prometheus/
        image: prom/prometheus:v2.5.0
        imagePullPolicy: IfNotPresent
        name: prometheus
        ports:
        - containerPort: 9090
          protocol: TCP
        volumeMounts:
        - mountPath: /etc/prometheus/
          name: prometheus-config
        - mountPath: /prometheus/
          name: prometheus-storage
        - mountPath: /etc/prometheus/secret/vault-operator-apiserver-cert
          name: vault-operator-apiserver-cert
      serviceAccountName: prometheus
      volumes:
      - configMap:
          defaultMode: 420
          name: prometheus-config
        name: prometheus-config
      - emptyDir: {}
        name: prometheus-storage
      - name: vault-operator-apiserver-cert
        secret:
          defaultMode: 420
          secretName: vault-operator-apiserver-cert
          items:
          - path: tls.crt
            key: tls.crt

Notice that, we have mounted vault-operator-apiserver-cert secret as a volume at /etc/prometheus/secret/vault-operator-apiserver-cert directory.

Now, let’s create the deployment,

$ kubectl apply -f https://github.com/kubevault/kubevault/raw/v2021.09.27/docs/examples/monitoring/vault-operator/prom-builtin-deployment.yaml
deployment.apps "prometheus" deleted

Verify Monitoring Metrics

Prometheus server is running on port 9090. We are going to use port forwarding to access Prometheus dashboard. Run following commands on a separate terminal,

$ kubectl get pod -n monitoring -l=app=prometheus
NAME                          READY   STATUS    RESTARTS   AGE
prometheus-8568c86d86-vpzx5   1/1     Running   0          102s

$ kubectl port-forward -n monitoring prometheus-8568c86d86-vpzx5  9090
Forwarding from 127.0.0.1:9090 -> 9090
Forwarding from [::1]:9090 -> 9090

Now, we can access the dashboard at localhost:9090. Open http://localhost:9090 in your browser. You should see the configured jobs as target and they are in UP state which means Prometheus is able collect metrics from them.

   builtin-prom-vault

Cleaning up

To uninstall Prometheus server follow this

To uninstall KubeVault operator follow this

To cleanup the Kubernetes resources created by this tutorial, run:

$ kubectl delete ns monitoring