k-cad

Kubernetes cadvisor to prometheus exporter.

About

k-cad is a simple exporter for Kubernetes cadvisor. cadvisor already expose its metrics in a Prometheus format, and the only way to get its metrics you need to do a static config for <host>/api/v1/nodes/<node-name>/proxy/metrics/cadvisor of course assuming you have cadvisor running in your cluster!

Assumptions

• Authentication happening from within a pod.
• Using Kubernetes DNS server kube-dns.
• Running k8s v1.15+

How to use it

k-cad should run as a Kubernetes pod in your cluster. Typically, you will need a single pod for your entire cluster.

To run k-cad successfully, you will need these three k8s resources:

• Deployment resource
• Service resource
• Service account resource

You will also need to configure Prometheus configs to point to k8s service for k-cad.

---

Deployment resource example:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: k-cad-deployment
  namespace: monitoring
  labels:
    app: k-cad
spec:
  selector:
    matchLabels:
      app: k-cad
  template:
    metadata:
      labels:
        app: k-cad
    spec:
      serviceAccountName: admin-user
      containers:
      - name: k-cad
        image: "yourdockerregistry/k-cad:v0.1.0"
        env:
        - name: PORT
          value: "41001"

---

Service account resource example

You will need to have a service account that will allow your pod to query Kubernetes API from within the pod.

apiVersion: v1
kind: ServiceAccount
metadata:
  name: admin-user
  namespace: monitoring
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: admin-user
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: admin-user
  namespace: monitoring

---

Service resource example

You will also need to create a Kubernetes service so that you can point your Prometheus static configs too.

apiVersion: v1
kind: Service
metadata:
  name: k-cad-service
  namespace: monitoring
  labels:
    app: k-cad
    belongTo: monitoring
spec:
  ports:
  - name: http
    port: 41001
    targetPort: 41001
  selector:
    app: k-cad

---

Here is an example of your Prometheus configs to query k-cad

- job_name: c-advisor
      static_configs:
      - targets:
        - k-cad-service.monitoring.svc.cluster.local:41001