main_test.go

/*
Copyright 2015 The Kubernetes Authors All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package main

import (
	"bytes"
	"context"
	"io/ioutil"
	"net/http/httptest"
	"sort"
	"strconv"
	"strings"
	"testing"
	"time"

	"github.com/prometheus/client_golang/prometheus"
	v1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/resource"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/client-go/kubernetes/fake"

	"k8s.io/kube-state-metrics/v2/internal/store"
	"k8s.io/kube-state-metrics/v2/pkg/allowdenylist"
	"k8s.io/kube-state-metrics/v2/pkg/metricshandler"
	"k8s.io/kube-state-metrics/v2/pkg/options"
)

func BenchmarkKubeStateMetrics(b *testing.B) {
	fixtureMultiplier := 1000
	requestCount := 1000

	b.Logf(
		"starting kube-state-metrics benchmark with fixtureMultiplier %v and requestCount %v",
		fixtureMultiplier,
		requestCount,
	)

	kubeClient := fake.NewSimpleClientset()

	if err := injectFixtures(kubeClient, fixtureMultiplier); err != nil {
		b.Errorf("error injecting resources: %v", err)
	}
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	reg := prometheus.NewRegistry()

	builder := store.NewBuilder()
	builder.WithMetrics(reg)
	builder.WithEnabledResources(options.DefaultResources.AsSlice())
	builder.WithKubeClient(kubeClient)
	builder.WithSharding(0, 1)
	builder.WithContext(ctx)
	builder.WithNamespaces(options.DefaultNamespaces)
	builder.WithGenerateStoreFunc(builder.DefaultGenerateStoreFunc())

	l, err := allowdenylist.New(map[string]struct{}{}, map[string]struct{}{})
	if err != nil {
		b.Fatal(err)
	}
	builder.WithAllowDenyList(l)

	builder.WithAllowLabels(map[string][]string{})

	// This test is not suitable to be compared in terms of time, as it includes
	// a one second wait. Use for memory allocation comparisons, profiling, ...
	handler := metricshandler.New(&options.Options{}, kubeClient, builder, false)
	b.Run("GenerateMetrics", func(b *testing.B) {
		handler.ConfigureSharding(ctx, 0, 1)

		// Wait for caches to fill
		time.Sleep(time.Second)
	})

	req := httptest.NewRequest("GET", "http://localhost:8080/metrics", nil)

	b.Run("MakeRequests", func(b *testing.B) {
		var accumulatedContentLength int

		for i := 0; i < requestCount; i++ {
			w := httptest.NewRecorder()
			handler.ServeHTTP(w, req)

			resp := w.Result()
			if resp.StatusCode != 200 {
				b.Fatalf("expected 200 status code but got %v", resp.StatusCode)
			}

			b.StopTimer()
			buf := bytes.Buffer{}
			buf.ReadFrom(resp.Body)
			accumulatedContentLength += buf.Len()
			b.StartTimer()
		}

		b.SetBytes(int64(accumulatedContentLength))
	})
}

// TestFullScrapeCycle is a simple smoke test covering the entire cycle from
// cache filling to scraping.
func TestFullScrapeCycle(t *testing.T) {
	t.Parallel()

	kubeClient := fake.NewSimpleClientset()

	err := pod(kubeClient, 0)
	if err != nil {
		t.Fatalf("failed to insert sample pod %v", err.Error())
	}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	reg := prometheus.NewRegistry()
	builder := store.NewBuilder()
	builder.WithMetrics(reg)
	builder.WithEnabledResources(options.DefaultResources.AsSlice())
	builder.WithKubeClient(kubeClient)
	builder.WithNamespaces(options.DefaultNamespaces)
	builder.WithGenerateStoreFunc(builder.DefaultGenerateStoreFunc())

	l, err := allowdenylist.New(map[string]struct{}{}, map[string]struct{}{})
	if err != nil {
		t.Fatal(err)
	}
	builder.WithAllowDenyList(l)
	builder.WithAllowLabels(map[string][]string{})

	handler := metricshandler.New(&options.Options{}, kubeClient, builder, false)
	handler.ConfigureSharding(ctx, 0, 1)

	// Wait for caches to fill
	time.Sleep(time.Second)

	req := httptest.NewRequest("GET", "http://localhost:8080/metrics", nil)

	w := httptest.NewRecorder()
	handler.ServeHTTP(w, req)

	resp := w.Result()
	if resp.StatusCode != 200 {
		t.Fatalf("expected 200 status code but got %v", resp.StatusCode)
	}

	body, _ := ioutil.ReadAll(resp.Body)

	expected := `# HELP kube_pod_info Information about pod.
# TYPE kube_pod_info gauge
kube_pod_info{namespace="default",pod="pod0",host_ip="1.1.1.1",pod_ip="1.2.3.4",uid="abc-0",node="node1",created_by_kind="<none>",created_by_name="<none>",priority_class="",host_network="false"} 1
# HELP kube_pod_start_time Start time in unix timestamp for a pod.
# TYPE kube_pod_start_time gauge
# HELP kube_pod_container_state_started Start time in unix timestamp for a pod container.
# TYPE kube_pod_container_state_started gauge
# HELP kube_pod_completion_time Completion time in unix timestamp for a pod.
# TYPE kube_pod_completion_time gauge
# HELP kube_pod_owner Information about the Pod's owner.
# TYPE kube_pod_owner gauge
kube_pod_owner{namespace="default",pod="pod0",owner_kind="<none>",owner_name="<none>",owner_is_controller="<none>"} 1
# HELP kube_pod_labels Kubernetes labels converted to Prometheus labels.
# TYPE kube_pod_labels gauge
kube_pod_labels{namespace="default",pod="pod0"} 1
# HELP kube_pod_created Unix creation timestamp
# TYPE kube_pod_created gauge
kube_pod_created{namespace="default",pod="pod0"} 1.5e+09
# HELP kube_pod_deletion_timestamp Unix deletion timestamp
# TYPE kube_pod_deletion_timestamp gauge
# HELP kube_pod_restart_policy Describes the restart policy in use by this pod.
# TYPE kube_pod_restart_policy gauge
kube_pod_restart_policy{namespace="default",pod="pod0",type="Always"} 1
# HELP kube_pod_status_scheduled_time Unix timestamp when pod moved into scheduled status
# TYPE kube_pod_status_scheduled_time gauge
# HELP kube_pod_status_unschedulable Describes the unschedulable status for the pod.
# TYPE kube_pod_status_unschedulable gauge
# HELP kube_pod_status_phase The pods current phase.
# TYPE kube_pod_status_phase gauge
kube_pod_status_phase{namespace="default",pod="pod0",phase="Pending"} 0
kube_pod_status_phase{namespace="default",pod="pod0",phase="Succeeded"} 0
kube_pod_status_phase{namespace="default",pod="pod0",phase="Failed"} 0
kube_pod_status_phase{namespace="default",pod="pod0",phase="Unknown"} 0
kube_pod_status_phase{namespace="default",pod="pod0",phase="Running"} 1
# HELP kube_pod_status_ready Describes whether the pod is ready to serve requests.
# TYPE kube_pod_status_ready gauge
# HELP kube_pod_status_scheduled Describes the status of the scheduling process for the pod.
# TYPE kube_pod_status_scheduled gauge
# HELP kube_pod_status_reason The pod status reasons
# TYPE kube_pod_status_reason gauge
kube_pod_status_reason{namespace="default",pod="pod0",reason="NodeLost"} 0
kube_pod_status_reason{namespace="default",pod="pod0",reason="Evicted"} 0
kube_pod_status_reason{namespace="default",pod="pod0",reason="UnexpectedAdmissionError"} 0
# HELP kube_pod_container_info Information about a container in a pod.
# TYPE kube_pod_container_info gauge
kube_pod_container_info{namespace="default",pod="pod0",container="container2",image="k8s.gcr.io/hyperkube2",image_id="docker://sha256:bbb",container_id="docker://cd456"} 1
kube_pod_container_info{namespace="default",pod="pod0",container="container3",image="k8s.gcr.io/hyperkube3",image_id="docker://sha256:ccc",container_id="docker://ef789"} 1
# HELP kube_pod_init_container_info Information about an init container in a pod.
# TYPE kube_pod_init_container_info gauge
# HELP kube_pod_container_status_waiting Describes whether the container is currently in waiting state.
# TYPE kube_pod_container_status_waiting gauge
kube_pod_container_status_waiting{namespace="default",pod="pod0",container="container2"} 1
kube_pod_container_status_waiting{namespace="default",pod="pod0",container="container3"} 0
# HELP kube_pod_init_container_status_waiting Describes whether the init container is currently in waiting state.
# TYPE kube_pod_init_container_status_waiting gauge
# HELP kube_pod_container_status_waiting_reason Describes the reason the container is currently in waiting state.
# TYPE kube_pod_container_status_waiting_reason gauge
kube_pod_container_status_waiting_reason{namespace="default",pod="pod0",container="container2",reason="ContainerCreating"} 0
kube_pod_container_status_waiting_reason{namespace="default",pod="pod0",container="container2",reason="CrashLoopBackOff"} 1
kube_pod_container_status_waiting_reason{namespace="default",pod="pod0",container="container2",reason="CreateContainerConfigError"} 0
kube_pod_container_status_waiting_reason{namespace="default",pod="pod0",container="container2",reason="ErrImagePull"} 0
kube_pod_container_status_waiting_reason{namespace="default",pod="pod0",container="container2",reason="ImagePullBackOff"} 0
kube_pod_container_status_waiting_reason{namespace="default",pod="pod0",container="container2",reason="CreateContainerError"} 0
kube_pod_container_status_waiting_reason{namespace="default",pod="pod0",container="container2",reason="InvalidImageName"} 0
kube_pod_container_status_waiting_reason{namespace="default",pod="pod0",container="container3",reason="ContainerCreating"} 0
kube_pod_container_status_waiting_reason{namespace="default",pod="pod0",container="container3",reason="CrashLoopBackOff"} 0
kube_pod_container_status_waiting_reason{namespace="default",pod="pod0",container="container3",reason="CreateContainerConfigError"} 0
kube_pod_container_status_waiting_reason{namespace="default",pod="pod0",container="container3",reason="ErrImagePull"} 0
kube_pod_container_status_waiting_reason{namespace="default",pod="pod0",container="container3",reason="ImagePullBackOff"} 0
kube_pod_container_status_waiting_reason{namespace="default",pod="pod0",container="container3",reason="CreateContainerError"} 0
kube_pod_container_status_waiting_reason{namespace="default",pod="pod0",container="container3",reason="InvalidImageName"} 0
# HELP kube_pod_init_container_status_waiting_reason Describes the reason the init container is currently in waiting state.
# TYPE kube_pod_init_container_status_waiting_reason gauge
# HELP kube_pod_container_status_running Describes whether the container is currently in running state.
# TYPE kube_pod_container_status_running gauge
kube_pod_container_status_running{namespace="default",pod="pod0",container="container2"} 0
kube_pod_container_status_running{namespace="default",pod="pod0",container="container3"} 0
# HELP kube_pod_init_container_status_running Describes whether the init container is currently in running state.
# TYPE kube_pod_init_container_status_running gauge
# HELP kube_pod_container_status_terminated Describes whether the container is currently in terminated state.
# TYPE kube_pod_container_status_terminated gauge
kube_pod_container_status_terminated{namespace="default",pod="pod0",container="container2"} 0
kube_pod_container_status_terminated{namespace="default",pod="pod0",container="container3"} 0
# HELP kube_pod_init_container_status_terminated Describes whether the init container is currently in terminated state.
# TYPE kube_pod_init_container_status_terminated gauge
# HELP kube_pod_container_status_terminated_reason Describes the reason the container is currently in terminated state.
# TYPE kube_pod_container_status_terminated_reason gauge
kube_pod_container_status_terminated_reason{namespace="default",pod="pod0",container="container2",reason="OOMKilled"} 0
kube_pod_container_status_terminated_reason{namespace="default",pod="pod0",container="container2",reason="Completed"} 0
kube_pod_container_status_terminated_reason{namespace="default",pod="pod0",container="container2",reason="Error"} 0
kube_pod_container_status_terminated_reason{namespace="default",pod="pod0",container="container2",reason="ContainerCannotRun"} 0
kube_pod_container_status_terminated_reason{namespace="default",pod="pod0",container="container2",reason="DeadlineExceeded"} 0
kube_pod_container_status_terminated_reason{namespace="default",pod="pod0",container="container2",reason="Evicted"} 0
kube_pod_container_status_terminated_reason{namespace="default",pod="pod0",container="container3",reason="OOMKilled"} 0
kube_pod_container_status_terminated_reason{namespace="default",pod="pod0",container="container3",reason="Completed"} 0
kube_pod_container_status_terminated_reason{namespace="default",pod="pod0",container="container3",reason="Error"} 0
kube_pod_container_status_terminated_reason{namespace="default",pod="pod0",container="container3",reason="ContainerCannotRun"} 0
kube_pod_container_status_terminated_reason{namespace="default",pod="pod0",container="container3",reason="DeadlineExceeded"} 0
kube_pod_container_status_terminated_reason{namespace="default",pod="pod0",container="container3",reason="Evicted"} 0
# HELP kube_pod_init_container_status_terminated_reason Describes the reason the init container is currently in terminated state.
# TYPE kube_pod_init_container_status_terminated_reason gauge
# HELP kube_pod_container_status_last_terminated_reason Describes the last reason the container was in terminated state.
# TYPE kube_pod_container_status_last_terminated_reason gauge
kube_pod_container_status_last_terminated_reason{namespace="default",pod="pod0",container="container2",reason="OOMKilled"} 1
kube_pod_container_status_last_terminated_reason{namespace="default",pod="pod0",container="container2",reason="Completed"} 0
kube_pod_container_status_last_terminated_reason{namespace="default",pod="pod0",container="container2",reason="Error"} 0
kube_pod_container_status_last_terminated_reason{namespace="default",pod="pod0",container="container2",reason="ContainerCannotRun"} 0
kube_pod_container_status_last_terminated_reason{namespace="default",pod="pod0",container="container2",reason="DeadlineExceeded"} 0
kube_pod_container_status_last_terminated_reason{namespace="default",pod="pod0",container="container2",reason="Evicted"} 0
kube_pod_container_status_last_terminated_reason{namespace="default",pod="pod0",container="container3",reason="OOMKilled"} 0
kube_pod_container_status_last_terminated_reason{namespace="default",pod="pod0",container="container3",reason="Completed"} 0
kube_pod_container_status_last_terminated_reason{namespace="default",pod="pod0",container="container3",reason="Error"} 0
kube_pod_container_status_last_terminated_reason{namespace="default",pod="pod0",container="container3",reason="ContainerCannotRun"} 0
kube_pod_container_status_last_terminated_reason{namespace="default",pod="pod0",container="container3",reason="DeadlineExceeded"} 0
kube_pod_container_status_last_terminated_reason{namespace="default",pod="pod0",container="container3",reason="Evicted"} 0
# HELP kube_pod_init_container_status_last_terminated_reason Describes the last reason the init container was in terminated state.
# TYPE kube_pod_init_container_status_last_terminated_reason gauge
# HELP kube_pod_container_status_ready Describes whether the containers readiness check succeeded.
# TYPE kube_pod_container_status_ready gauge
kube_pod_container_status_ready{namespace="default",pod="pod0",container="container2"} 0
kube_pod_container_status_ready{namespace="default",pod="pod0",container="container3"} 0
# HELP kube_pod_init_container_status_ready Describes whether the init containers readiness check succeeded.
# TYPE kube_pod_init_container_status_ready gauge
# HELP kube_pod_container_status_restarts_total The number of container restarts per container.
# TYPE kube_pod_container_status_restarts_total counter
kube_pod_container_status_restarts_total{namespace="default",pod="pod0",container="container2"} 0
kube_pod_container_status_restarts_total{namespace="default",pod="pod0",container="container3"} 0
# HELP kube_pod_init_container_status_restarts_total The number of restarts for the init container.
# TYPE kube_pod_init_container_status_restarts_total counter
# HELP kube_pod_container_resource_requests_cpu_cores The number of CPU cores requested by a container.
# TYPE kube_pod_container_resource_requests_cpu_cores gauge
kube_pod_container_resource_requests_cpu_cores{namespace="default",pod="pod0",container="pod1_con1"} 0.2
kube_pod_container_resource_requests_cpu_cores{namespace="default",pod="pod0",container="pod1_con2"} 0.3
# HELP kube_pod_container_resource_requests_memory_bytes Bytes of memory requested by a container.
# TYPE kube_pod_container_resource_requests_memory_bytes gauge
kube_pod_container_resource_requests_memory_bytes{namespace="default",pod="pod0",container="pod1_con1"} 1e+08
kube_pod_container_resource_requests_memory_bytes{namespace="default",pod="pod0",container="pod1_con2"} 2e+08
# HELP kube_pod_container_resource_requests_storage_bytes Bytes of storage requested by a container.
# TYPE kube_pod_container_resource_requests_storage_bytes gauge
kube_pod_container_resource_requests_storage_bytes{namespace="default",pod="pod0",container="pod1_con1"} 4e+08
# HELP kube_pod_container_resource_requests_ephemeral_storage_bytes Bytes of ephemeral-storage requested by a container.
# TYPE kube_pod_container_resource_requests_ephemeral_storage_bytes gauge
kube_pod_container_resource_requests_ephemeral_storage_bytes{namespace="default",pod="pod0",container="pod1_con1"} 3e+08
# HELP kube_pod_container_resource_requests The number of requested request resource by a container.
# TYPE kube_pod_container_resource_requests gauge
kube_pod_container_resource_requests{namespace="default",pod="pod0",container="pod1_con1",resource="nvidia_com_gpu",unit="integer"} 1
# HELP kube_pod_container_resource_limits_cpu_cores The number of CPU cores requested limit by a container.
# TYPE kube_pod_container_resource_limits_cpu_cores gauge
kube_pod_container_resource_limits_cpu_cores{namespace="default",pod="pod0",container="pod1_con1"} 0.2
kube_pod_container_resource_limits_cpu_cores{namespace="default",pod="pod0",container="pod1_con2"} 0.3
# HELP kube_pod_container_resource_limits_memory_bytes Bytes of memory requested limit by a container.
# TYPE kube_pod_container_resource_limits_memory_bytes gauge
kube_pod_container_resource_limits_memory_bytes{namespace="default",pod="pod0",container="pod1_con1"} 1e+08
kube_pod_container_resource_limits_memory_bytes{namespace="default",pod="pod0",container="pod1_con2"} 2e+08
# HELP kube_pod_container_resource_limits_storage_bytes Bytes of storage requested limit by a container.
# TYPE kube_pod_container_resource_limits_storage_bytes gauge
kube_pod_container_resource_limits_storage_bytes{namespace="default",pod="pod0",container="pod1_con1"} 4e+08
# HELP kube_pod_container_resource_limits_ephemeral_storage_bytes Bytes of ephemeral-storage requested limit by a container.
# TYPE kube_pod_container_resource_limits_ephemeral_storage_bytes gauge
kube_pod_container_resource_limits_ephemeral_storage_bytes{namespace="default",pod="pod0",container="pod1_con1"} 3e+08
# HELP kube_pod_container_resource_limits The number of requested limit resource by a container.
# TYPE kube_pod_container_resource_limits gauge
kube_pod_container_resource_limits{namespace="default",pod="pod0",container="pod1_con1",resource="nvidia_com_gpu",unit="integer"} 1
# HELP kube_pod_init_container_resource_requests_cpu_cores The number of CPU cores requested by an init container.
# TYPE kube_pod_init_container_resource_requests_cpu_cores gauge
# HELP kube_pod_init_container_resource_requests_memory_bytes Bytes of memory requested by an init container.
# TYPE kube_pod_init_container_resource_requests_memory_bytes gauge
# HELP kube_pod_init_container_resource_requests_storage_bytes Bytes of storage requested by an init container.
# TYPE kube_pod_init_container_resource_requests_storage_bytes gauge
# HELP kube_pod_init_container_resource_requests_ephemeral_storage_bytes Bytes of ephemeral-storage requested by an init container.
# TYPE kube_pod_init_container_resource_requests_ephemeral_storage_bytes gauge
# HELP kube_pod_init_container_resource_requests The number of requested request resource by an init container.
# TYPE kube_pod_init_container_resource_requests gauge
# HELP kube_pod_init_container_resource_limits_cpu_cores The number of CPU cores requested limit by an init container.
# TYPE kube_pod_init_container_resource_limits_cpu_cores gauge
# HELP kube_pod_init_container_resource_limits_memory_bytes Bytes of memory requested limit by an init container.
# TYPE kube_pod_init_container_resource_limits_memory_bytes gauge
# HELP kube_pod_init_container_resource_limits_storage_bytes Bytes of storage requested limit by an init container.
# TYPE kube_pod_init_container_resource_limits_storage_bytes gauge
# HELP kube_pod_init_container_resource_limits_ephemeral_storage_bytes Bytes of ephemeral-storage requested limit by an init container.
# TYPE kube_pod_init_container_resource_limits_ephemeral_storage_bytes gauge
# HELP kube_pod_init_container_resource_limits The number of requested limit resource by an init container.
# TYPE kube_pod_init_container_resource_limits gauge
# HELP kube_pod_spec_volumes_persistentvolumeclaims_info Information about persistentvolumeclaim volumes in a pod.
# TYPE kube_pod_spec_volumes_persistentvolumeclaims_info gauge
# HELP kube_pod_spec_volumes_persistentvolumeclaims_readonly Describes whether a persistentvolumeclaim is mounted read only.
# TYPE kube_pod_spec_volumes_persistentvolumeclaims_readonly gauge
# HELP kube_pod_overhead_cpu_cores The pod overhead in regards to cpu cores associated with running a pod.
# TYPE kube_pod_overhead_cpu_cores gauge
# HELP kube_pod_overhead_memory_bytes The pod overhead in regards to memory associated with running a pod.
# TYPE kube_pod_overhead_memory_bytes gauge
`

	expectedSplit := strings.Split(strings.TrimSpace(expected), "\n")
	sort.Strings(expectedSplit)

	gotSplit := strings.Split(strings.TrimSpace(string(body)), "\n")

	gotFiltered := []string{}
	for _, l := range gotSplit {
		if strings.Contains(l, "kube_pod_") {
			gotFiltered = append(gotFiltered, l)
		}
	}

	sort.Strings(gotFiltered)

	if len(expectedSplit) != len(gotFiltered) {
		t.Fatalf("expected different output length, expected \n\n%s\n\ngot\n\n%s", expected, string(body))
	}

	for i := 0; i < len(expectedSplit); i++ {
		if expectedSplit[i] != gotFiltered[i] {
			t.Fatalf("expected:\n\n%v, but got:\n\n%v", expectedSplit[i], gotFiltered[i])
		}
	}
}

// TestShardingEquivalenceScrapeCycle is a simple smoke test covering the entire cycle from
// cache filling to scraping comparing a sharded with an unsharded setup.
func TestShardingEquivalenceScrapeCycle(t *testing.T) {
	t.Parallel()

	kubeClient := fake.NewSimpleClientset()

	for i := 0; i < 10; i++ {
		err := pod(kubeClient, i)
		if err != nil {
			t.Fatalf("failed to insert sample pod %v", err.Error())
		}
	}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	l, err := allowdenylist.New(map[string]struct{}{}, map[string]struct{}{})
	if err != nil {
		t.Fatal(err)
	}

	reg := prometheus.NewRegistry()
	unshardedBuilder := store.NewBuilder()
	unshardedBuilder.WithMetrics(reg)
	unshardedBuilder.WithEnabledResources(options.DefaultResources.AsSlice())
	unshardedBuilder.WithKubeClient(kubeClient)
	unshardedBuilder.WithNamespaces(options.DefaultNamespaces)
	unshardedBuilder.WithAllowDenyList(l)
	unshardedBuilder.WithAllowLabels(map[string][]string{})
	unshardedBuilder.WithGenerateStoreFunc(unshardedBuilder.DefaultGenerateStoreFunc())

	unshardedHandler := metricshandler.New(&options.Options{}, kubeClient, unshardedBuilder, false)
	unshardedHandler.ConfigureSharding(ctx, 0, 1)

	regShard1 := prometheus.NewRegistry()
	shardedBuilder1 := store.NewBuilder()
	shardedBuilder1.WithMetrics(regShard1)
	shardedBuilder1.WithEnabledResources(options.DefaultResources.AsSlice())
	shardedBuilder1.WithKubeClient(kubeClient)
	shardedBuilder1.WithNamespaces(options.DefaultNamespaces)
	shardedBuilder1.WithAllowDenyList(l)
	shardedBuilder1.WithAllowLabels(map[string][]string{})
	shardedBuilder1.WithGenerateStoreFunc(shardedBuilder1.DefaultGenerateStoreFunc())

	shardedHandler1 := metricshandler.New(&options.Options{}, kubeClient, shardedBuilder1, false)
	shardedHandler1.ConfigureSharding(ctx, 0, 2)

	regShard2 := prometheus.NewRegistry()
	shardedBuilder2 := store.NewBuilder()
	shardedBuilder2.WithMetrics(regShard2)
	shardedBuilder2.WithEnabledResources(options.DefaultResources.AsSlice())
	shardedBuilder2.WithKubeClient(kubeClient)
	shardedBuilder2.WithNamespaces(options.DefaultNamespaces)
	shardedBuilder2.WithAllowDenyList(l)
	shardedBuilder2.WithAllowLabels(map[string][]string{})
	shardedBuilder2.WithGenerateStoreFunc(shardedBuilder2.DefaultGenerateStoreFunc())

	shardedHandler2 := metricshandler.New(&options.Options{}, kubeClient, shardedBuilder2, false)
	shardedHandler2.ConfigureSharding(ctx, 1, 2)

	// Wait for caches to fill
	time.Sleep(time.Second)

	// unsharded request as the controlled environment
	req := httptest.NewRequest("GET", "http://localhost:8080/metrics", nil)

	w := httptest.NewRecorder()
	unshardedHandler.ServeHTTP(w, req)

	resp := w.Result()
	if resp.StatusCode != 200 {
		t.Fatalf("expected 200 status code but got %v", resp.StatusCode)
	}

	body, _ := ioutil.ReadAll(resp.Body)
	expected := string(body)

	// sharded requests
	//
	// request first shard
	req = httptest.NewRequest("GET", "http://localhost:8080/metrics", nil)

	w = httptest.NewRecorder()
	shardedHandler1.ServeHTTP(w, req)

	resp = w.Result()
	if resp.StatusCode != 200 {
		t.Fatalf("expected 200 status code but got %v", resp.StatusCode)
	}

	body, _ = ioutil.ReadAll(resp.Body)
	got1 := string(body)

	// request second shard
	req = httptest.NewRequest("GET", "http://localhost:8080/metrics", nil)

	w = httptest.NewRecorder()
	shardedHandler2.ServeHTTP(w, req)

	resp = w.Result()
	if resp.StatusCode != 200 {
		t.Fatalf("expected 200 status code but got %v", resp.StatusCode)
	}

	body, _ = ioutil.ReadAll(resp.Body)
	got2 := string(body)

	// normalize results:

	expectedSplit := strings.Split(strings.TrimSpace(expected), "\n")
	sort.Strings(expectedSplit)

	expectedFiltered := []string{}
	for _, l := range expectedSplit {
		if strings.HasPrefix(l, "kube_pod_") {
			expectedFiltered = append(expectedFiltered, l)
		}
	}

	got1Split := strings.Split(strings.TrimSpace(got1), "\n")
	sort.Strings(got1Split)

	got1Filtered := []string{}
	for _, l := range got1Split {
		if strings.HasPrefix(l, "kube_pod_") {
			got1Filtered = append(got1Filtered, l)
		}
	}

	got2Split := strings.Split(strings.TrimSpace(got2), "\n")
	sort.Strings(got2Split)

	got2Filtered := []string{}
	for _, l := range got2Split {
		if strings.HasPrefix(l, "kube_pod_") {
			got2Filtered = append(got2Filtered, l)
		}
	}

	// total metrics should be equal
	if len(expectedFiltered) != (len(got1Filtered) + len(got2Filtered)) {
		t.Fatalf("expected different output length, expected total %d got 1) %d 2) %d", len(expectedFiltered), len(got1Filtered), len(got2Filtered))
	}
	// smoke test to test that each shard actually represents a subset
	if len(got1Filtered) == 0 {
		t.Fatal("shard 1 has 0 metrics when it shouldn't")
	}
	if len(got2Filtered) == 0 {
		t.Fatal("shard 2 has 0 metrics when it shouldn't")
	}

	gotFiltered := append(got1Filtered, got2Filtered...)
	sort.Strings(gotFiltered)

	for i := 0; i < len(expectedFiltered); i++ {
		expected := strings.TrimSpace(expectedFiltered[i])
		got := strings.TrimSpace(gotFiltered[i])
		if expected != got {
			t.Fatalf("\n\nexpected:\n\n%q\n\nbut got:\n\n%q\n\n", expected, got)
		}
	}
}

func injectFixtures(client *fake.Clientset, multiplier int) error {
	creators := []func(*fake.Clientset, int) error{
		configMap,
		service,
		pod,
	}

	for _, c := range creators {
		for i := 0; i < multiplier; i++ {
			err := c(client, i)

			if err != nil {
				return err
			}
		}
	}

	return nil
}

func configMap(client *fake.Clientset, index int) error {
	i := strconv.Itoa(index)

	configMap := v1.ConfigMap{
		ObjectMeta: metav1.ObjectMeta{
			Name:            "configmap" + i,
			ResourceVersion: "123456",
			UID:             types.UID("abc-" + i),
		},
	}
	_, err := client.CoreV1().ConfigMaps(metav1.NamespaceDefault).Create(context.TODO(), &configMap, metav1.CreateOptions{})
	return err
}

func service(client *fake.Clientset, index int) error {
	i := strconv.Itoa(index)

	service := v1.Service{
		ObjectMeta: metav1.ObjectMeta{
			Name:            "service" + i,
			ResourceVersion: "123456",
			UID:             types.UID("abc-" + i),
		},
	}
	_, err := client.CoreV1().Services(metav1.NamespaceDefault).Create(context.TODO(), &service, metav1.CreateOptions{})
	return err
}

func pod(client *fake.Clientset, index int) error {
	i := strconv.Itoa(index)

	pod := v1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:              "pod" + i,
			CreationTimestamp: metav1.Time{Time: time.Unix(1500000000, 0)},
			Namespace:         "default",
			UID:               types.UID("abc-" + i),
		},
		Spec: v1.PodSpec{
			RestartPolicy: v1.RestartPolicyAlways,
			NodeName:      "node1",
			Containers: []v1.Container{
				{
					Name: "pod1_con1",
					Resources: v1.ResourceRequirements{
						Requests: map[v1.ResourceName]resource.Quantity{
							v1.ResourceCPU:                    resource.MustParse("200m"),
							v1.ResourceMemory:                 resource.MustParse("100M"),
							v1.ResourceEphemeralStorage:       resource.MustParse("300M"),
							v1.ResourceStorage:                resource.MustParse("400M"),
							v1.ResourceName("nvidia.com/gpu"): resource.MustParse("1"),
						},
						Limits: map[v1.ResourceName]resource.Quantity{
							v1.ResourceCPU:                    resource.MustParse("200m"),
							v1.ResourceMemory:                 resource.MustParse("100M"),
							v1.ResourceEphemeralStorage:       resource.MustParse("300M"),
							v1.ResourceStorage:                resource.MustParse("400M"),
							v1.ResourceName("nvidia.com/gpu"): resource.MustParse("1"),
						},
					},
				},
				{
					Name: "pod1_con2",
					Resources: v1.ResourceRequirements{
						Requests: map[v1.ResourceName]resource.Quantity{
							v1.ResourceCPU:    resource.MustParse("300m"),
							v1.ResourceMemory: resource.MustParse("200M"),
						},
						Limits: map[v1.ResourceName]resource.Quantity{
							v1.ResourceCPU:    resource.MustParse("300m"),
							v1.ResourceMemory: resource.MustParse("200M"),
						},
					},
				},
			},
		},
		Status: v1.PodStatus{
			HostIP: "1.1.1.1",
			PodIP:  "1.2.3.4",
			Phase:  v1.PodRunning,
			ContainerStatuses: []v1.ContainerStatus{
				{
					Name:        "container2",
					Image:       "k8s.gcr.io/hyperkube2",
					ImageID:     "docker://sha256:bbb",
					ContainerID: "docker://cd456",
					State: v1.ContainerState{
						Waiting: &v1.ContainerStateWaiting{
							Reason: "CrashLoopBackOff",
						},
					},
					LastTerminationState: v1.ContainerState{
						Terminated: &v1.ContainerStateTerminated{
							Reason: "OOMKilled",
						},
					},
				},
				{
					Name:        "container3",
					Image:       "k8s.gcr.io/hyperkube3",
					ImageID:     "docker://sha256:ccc",
					ContainerID: "docker://ef789",
				},
			},
		},
	}

	_, err := client.CoreV1().Pods(metav1.NamespaceDefault).Create(context.TODO(), &pod, metav1.CreateOptions{})
	return err
}