Send parallel API requests to kube-api server

metrics-role.yaml

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: prometheus
rules:
- apiGroups: [""]
  resources:
  - nodes
  - nodes/metrics
  - services
  - endpoints
  - pods
  verbs: ["get", "list", "watch"]
- apiGroups:
  - extensions
  - networking.k8s.io
  resources:
  - ingresses
  verbs: ["get", "list", "watch"]
- nonResourceURLs: ["/metrics", "/metrics/cadvisor"]
  verbs: ["get"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: prometheus
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: prometheus
subjects:
- kind: ServiceAccount
  name: default
  namespace: default

query-kubeapiserver.sh

#!/bin/bash -eux

# brettmilford: added kubeapiserver /metrics gathering
# This file is based on https://code.launchpad.net/~freyes/+git/experiment
# Modified to use xargs instead of parallel

# source: https://kubernetes.io/docs/tasks/administer-cluster/access-cluster-api/

PARALLEL_REQS=20
SLEEP_SECS=0.1
TEMPLOG=$(mktemp).log
TEMPLOGMETRICS=$(mktemp)-metrics.log
K8S_ENDPOINT='/api'

# Select name of cluster you want to interact with from above output:
export CLUSTER_NAME="juju-cluster"

# Point to the API server referring the cluster name
APISERVER=$(kubectl config view -o jsonpath="{.clusters[?(@.name==\"$CLUSTER_NAME\")].cluster.server}")

# Gets the token value
TOKEN=$(kubectl get secrets -o jsonpath="{.items[?(@.metadata.annotations['kubernetes\.io/service-account\.name']=='default')].data.token}"|base64 --decode)

# trap ctrl-c and call ctrl_c()
trap ctrl_c INT

function ctrl_c() {
  local DEST=query-kubeapiserver.$(date '+%Y%m%d_%H%M').log
  local DESTMETRICS=query-kubeapiserver-metrics.$(date '+%Y%m%d_%H%M').log
  mv $TEMPLOG $DEST
  mv $TEMPLOGMETRICS $DESTMETRICS
  echo -e "\noutput at $DEST \nmetrics at $DESTMETRICS"
  exit 0
}

#set +x
(
  ts_and_log() {
    while read line; do
      # filter comments
      [[ "$line" =~ ^\# ]] || echo "$(date +%d-%m-%YT%H:%m:%S) $line" 2>&1 >> $TEMPLOGMETRICS
    done
  }
  while true; do
    (curl -s -X GET "${APISERVER}/metrics" --header "Authorization: Bearer $TOKEN" --insecure) | ts_and_log
    /bin/sleep 5
  done
) &

while true; do
  seq $PARALLEL_REQS | xargs -I {} -n1 -P$PARALLEL_REQS curl -s -X GET $APISERVER$K8S_ENDPOINT --header "Authorization: Bearer $TOKEN" --insecure 2>&1 >> $TEMPLOG
  /bin/sleep $SLEEP_SECS
done