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generic ephemeral volume: simpler metrics

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A CounterVector with status as label may create unnecessary overhead
and using the success case with the empty label value wasn't
easy. It's better to have two seperate counters, one for total number
of calls and one for failed calls.
This commit is contained in:
Patrick Ohly 2021-02-23 21:23:31 +01:00
parent ef6f65bead
commit 98f75290ba
3 changed files with 29 additions and 31 deletions
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11
pkg/controller/volume/ephemeral/controller.go
View File

@ -25,7 +25,6 @@ import (
v1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/api/errors"
apierrors "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/util/runtime"
"k8s.io/apimachinery/pkg/util/wait"
@ -282,16 +281,10 @@ func (ec *ephemeralController) handleVolume(pod *v1.Pod, vol v1.Volume) error {
},
Spec: ephemeral.VolumeClaimTemplate.Spec,
}
ephemeralvolumemetrics.EphemeralVolumeCreateAttempts.Inc()
_, err = ec.kubeClient.CoreV1().PersistentVolumeClaims(pod.Namespace).Create(context.TODO(), pvc, metav1.CreateOptions{})
reason := ""
if err != nil {
reason = string(apierrors.ReasonForError(err))
if reason == "" {
reason = "Unknown"
}
}
ephemeralvolumemetrics.EphemeralVolumeCreate.WithLabelValues(reason).Inc()
if err != nil {
ephemeralvolumemetrics.EphemeralVolumeCreateFailures.Inc()
return fmt.Errorf("create PVC %s: %v", pvcName, err)
}
return nil

22
pkg/controller/volume/ephemeral/controller_test.go
View File

@ -22,7 +22,7 @@ import (
"sort"
"testing"
"k8s.io/api/core/v1"
v1 "k8s.io/api/core/v1"
// storagev1 "k8s.io/api/storage/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
// "k8s.io/apimachinery/pkg/types"
@ -116,7 +116,7 @@ func TestSyncHandler(t *testing.T) {
name: "create-conflict",
pods: []*v1.Pod{testPodWithEphemeral},
podKey: podKey(testPodWithEphemeral),
expectedMetrics: expectedMetrics{0, 1},
expectedMetrics: expectedMetrics{1, 1},
expectedError: true,
},
}
@ -139,7 +139,7 @@ func TestSyncHandler(t *testing.T) {
}
fakeKubeClient := createTestClient(objects...)
if tc.expectedMetrics.numConflicts > 0 {
if tc.expectedMetrics.numFailures > 0 {
fakeKubeClient.PrependReactor("create", "persistentvolumeclaims", func(action k8stesting.Action) (handled bool, ret runtime.Object, err error) {
return true, nil, apierrors.NewConflict(action.GetResource().GroupResource(), "fake name", errors.New("fake conflict"))
})
@ -245,22 +245,22 @@ func createTestClient(objects ...runtime.Object) *fake.Clientset {
// Metrics helpers
type expectedMetrics struct {
numCreated int
numConflicts int
numCreated int
numFailures int
}
func expectMetrics(t *testing.T, em expectedMetrics) {
t.Helper()
actualCreated, err := testutil.GetCounterMetricValue(ephemeralvolumemetrics.EphemeralVolumeCreate.WithLabelValues(""))
actualCreated, err := testutil.GetCounterMetricValue(ephemeralvolumemetrics.EphemeralVolumeCreateAttempts)
handleErr(t, err, "ephemeralVolumeCreate")
if actualCreated != float64(em.numCreated) {
t.Errorf("Expected PVCs to be created %d, got %v", em.numCreated, actualCreated)
}
actualConflicts, err := testutil.GetCounterMetricValue(ephemeralvolumemetrics.EphemeralVolumeCreate.WithLabelValues("Conflict"))
actualConflicts, err := testutil.GetCounterMetricValue(ephemeralvolumemetrics.EphemeralVolumeCreateFailures)
handleErr(t, err, "ephemeralVolumeCreate/Conflict")
if actualConflicts != float64(em.numConflicts) {
t.Errorf("Expected PVCs to have conflicts %d, got %v", em.numConflicts, actualConflicts)
if actualConflicts != float64(em.numFailures) {
t.Errorf("Expected PVCs to have conflicts %d, got %v", em.numFailures, actualConflicts)
}
}
@ -272,6 +272,6 @@ func handleErr(t *testing.T, err error, metricName string) {
func setupMetrics() {
ephemeralvolumemetrics.RegisterMetrics()
ephemeralvolumemetrics.EphemeralVolumeCreate.Delete(map[string]string{"reason": ""})
ephemeralvolumemetrics.EphemeralVolumeCreate.Delete(map[string]string{"reason": "Conflict"})
ephemeralvolumemetrics.EphemeralVolumeCreateAttempts.Reset()
ephemeralvolumemetrics.EphemeralVolumeCreateFailures.Reset()
}

27
pkg/controller/volume/ephemeral/metrics/metrics.go
View File

@ -27,20 +27,24 @@ import (
const EphemeralVolumeSubsystem = "ephemeral_volume_controller"
var (
// EphemeralVolumeCreate tracks the number of
// PersistentVolumeClaims().Create calls for each failure
// reason
// (https://pkg.go.dev/k8s.io/apimachinery@v0.20.2/pkg/apis/meta/v1#StatusReason),
// with empty for successful calls.
EphemeralVolumeCreate = metrics.NewCounterVec(
// EphemeralVolumeCreateAttempts tracks the number of
// PersistentVolumeClaims().Create calls (both successful and unsuccessful)
EphemeralVolumeCreateAttempts = metrics.NewCounter(
&metrics.CounterOpts{
Subsystem: EphemeralVolumeSubsystem,
Name: "create",
Name: "create_total",
Help: "Number of PersistenVolumeClaims creation requests",
StabilityLevel: metrics.ALPHA,
},
[]string{"reason"},
)
})
// EphemeralVolumeCreateFailures tracks the number of unsuccessful
// PersistentVolumeClaims().Create calls
EphemeralVolumeCreateFailures = metrics.NewCounter(
&metrics.CounterOpts{
Subsystem: EphemeralVolumeSubsystem,
Name: "create_failures_total",
Help: "Number of PersistenVolumeClaims creation requests",
StabilityLevel: metrics.ALPHA,
})
)
var registerMetrics sync.Once
@ -48,6 +52,7 @@ var registerMetrics sync.Once
// RegisterMetrics registers EphemeralVolume metrics.
func RegisterMetrics() {
registerMetrics.Do(func() {
legacyregistry.MustRegister(EphemeralVolumeCreate)
legacyregistry.MustRegister(EphemeralVolumeCreateAttempts)
legacyregistry.MustRegister(EphemeralVolumeCreateFailures)
})
}