prometheus-adapter-configs

1. Prometheus Adapter Installation

• Create namespace custom-metrics.

  $ kubectl create namespace custom-metrics
  
  Output:
  namespace/custom-metrics created

• Create service certificate. Follow Serving Certificates, Authentication, and Authorization to create serving certificate. For this sample we can use certs in the directory prometheus-adapter/certs. Create secret cm-adapter-serving-certs as follows.

  $ kubectl create secret generic cm-adapter-serving-certs \
          --from-file=serving-ca.crt=certs/serving-ca.crt \
          --from-file=serving-ca.key=certs/serving-ca.key \
          -n custom-metrics
  
  Output:
  secret/cm-adapter-serving-certs created

• Install Prometheus Adapter (version 0.7.0 for this sample) in Kubernetes cluster.

  $ kubectl apply -f .
  
  Output:
  clusterrolebinding.rbac.authorization.k8s.io/custom-metrics:system:auth-delegator created
  rolebinding.rbac.authorization.k8s.io/custom-metrics-auth-reader created
  deployment.apps/custom-metrics-apiserver created
  clusterrolebinding.rbac.authorization.k8s.io/custom-metrics-resource-reader created
  serviceaccount/custom-metrics-apiserver created
  service/custom-metrics-apiserver created
  apiservice.apiregistration.k8s.io/v1beta1.custom.metrics.k8s.io created
  clusterrole.rbac.authorization.k8s.io/custom-metrics-server-resources created
  configmap/adapter-config created
  clusterrole.rbac.authorization.k8s.io/custom-metrics-resource-reader created
  clusterrolebinding.rbac.authorization.k8s.io/hpa-controller-custom-metrics created

  In the directory prometheus-adapter we have specified configurations for Prometheus Adapter. custom-metrics-config-map.yaml contains rules defined for this sample.

  # rule for products backend service
  - seriesQuery: '{__name__=~"^.*_http_requests_total"}'
    resources:
      overrides:
        namespace: {resource: "namespace"}
        pod: {resource: "pod"}
    name:
      matches: "^(.*)_http_requests_total"
      as: "${1}_http_requests_total_per_second"
    metricsQuery: 'sum(rate(<<.Series>>{<<.LabelMatchers>>,http_url!=""}[1m])) by (<<.GroupBy>>)'
  

• Test the Prometheus Adapter deployment executing follows.

  $ kubectl get --raw /apis/custom.metrics.k8s.io/v1beta1
  
  Output:
  {"kind":"APIResourceList","apiVersion":"v1","groupVersion":"custom.metrics.k8s.io/v1beta1","resources":[]}