Metrics Scrapper

This is Prometheus Integration with rest service exposed using golang application. Golang application is deployed on kubernetes cluster and exposed as rest endpoint url.

There are two matrics exposed:

1. Gauge (To count number of pods in cluster)
2. Counter (Couting the total request hit count)

Pre-requisite:

Create RBAC rules to allow go application to get pod list on cluster level.

kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: pod-reader
rules:
  - verbs:
      - get
      - watch
      - list
    apiGroups:
      - ''
    resources:
      - pods

kind: ServiceAccount
apiVersion: v1
metadata:
  name: pod-service-account
  namespace: <namespace-name>

kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: pod-reader-global
subjects:
  - kind: ServiceAccount
    name: pod-service-account
    namespace: mukul-test
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: pod-reader

Build Metrics Go application, create a docker image and deploy on kubernetes

Clone code first:

git clone https://github.com/mukul4u2005/matrics.git
 

Build code:

GOOS=linux go build -o ./matrix-app .

Build docker image:

docker build -t matrix-app .

Tag image

docker tag matrix-app mpdocker2017/matrix-app:latest

Push image to Dockerhub

docker push mpdocker2017/matrix-app:latest   

Configure configmap and secret for Prometheus and metrics service

Create Secret for cluster api call, this secret is referenced in metrics deployment to configure as env. variables:

 kubectl create secret generic cluster-secret --from-literal=TOKEN=<token> --from-literal=API_URL=<api-url>

Create Prometheus config map for scrapper configuration (For prometheus deployment):

kubectl create configmap prome-config --from-file=<path>/prometheus.yml

Deploy Application on Kubernetes cluster and expose

Create deployment using yaml available in config folder:

For metrics service (Please change the image url):

kubectl apply -f metrics-deployment.yml

Create Prometheus deployment:

kubectl apply -f prom-deployment.yml

Access Prometheus using port-forward

kubectl port-forward pod-name 9090:9090