mirror of
https://github.com/k3s-io/kubernetes.git
synced 2025-07-30 15:05:27 +00:00
Add unit test for DisruptionController retry logic
This tests the PDB status update path in DisruptionController and
asserts that conflicting writes (with eviciton handler) are handled
gracefully.
This adds the client-go fake.Clientset into our tests, because that is
the layer required for injecting update failures.
This also adds a TestMain so that DisruptionController logs can be
enabled during test. e.g.,
go test ./pkg/controller/disruption -v -args -v=4
This commit is contained in:
Jonathan Basseri
parent
8835f6bb00
commit
c8d937c5f1
@ -55,6 +55,7 @@ go_test(
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"//staging/src/k8s.io/api/core/v1:go_default_library",
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"//staging/src/k8s.io/api/policy/v1beta1:go_default_library",
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"//staging/src/k8s.io/apimachinery/pkg/api/equality:go_default_library",
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"//staging/src/k8s.io/apimachinery/pkg/api/errors:go_default_library",
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"//staging/src/k8s.io/apimachinery/pkg/api/meta/testrestmapper:go_default_library",
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"//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
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"//staging/src/k8s.io/apimachinery/pkg/runtime:go_default_library",
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@ -62,11 +63,14 @@ go_test(
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"//staging/src/k8s.io/apimachinery/pkg/types:go_default_library",
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"//staging/src/k8s.io/apimachinery/pkg/util/intstr:go_default_library",
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"//staging/src/k8s.io/apimachinery/pkg/util/uuid:go_default_library",
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"//staging/src/k8s.io/apimachinery/pkg/util/wait:go_default_library",
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"//staging/src/k8s.io/client-go/informers:go_default_library",
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"//staging/src/k8s.io/client-go/kubernetes/fake:go_default_library",
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"//staging/src/k8s.io/client-go/scale/fake:go_default_library",
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"//staging/src/k8s.io/client-go/testing:go_default_library",
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"//staging/src/k8s.io/client-go/tools/cache:go_default_library",
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"//staging/src/k8s.io/client-go/util/workqueue:go_default_library",
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"//vendor/k8s.io/klog:go_default_library",
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"//vendor/k8s.io/utils/pointer:go_default_library",
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],
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)
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@ -17,16 +17,21 @@ limitations under the License.
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package disruption
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import (
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"context"
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"flag"
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"fmt"
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"os"
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"runtime/debug"
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"sync"
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"testing"
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"time"
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apps "k8s.io/api/apps/v1"
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autoscalingapi "k8s.io/api/autoscaling/v1"
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"k8s.io/api/core/v1"
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v1 "k8s.io/api/core/v1"
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policy "k8s.io/api/policy/v1beta1"
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apiequality "k8s.io/apimachinery/pkg/api/equality"
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"k8s.io/apimachinery/pkg/api/errors"
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"k8s.io/apimachinery/pkg/api/meta/testrestmapper"
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metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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"k8s.io/apimachinery/pkg/runtime"
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@ -34,11 +39,14 @@ import (
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"k8s.io/apimachinery/pkg/types"
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"k8s.io/apimachinery/pkg/util/intstr"
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"k8s.io/apimachinery/pkg/util/uuid"
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"k8s.io/apimachinery/pkg/util/wait"
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"k8s.io/client-go/informers"
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"k8s.io/client-go/kubernetes/fake"
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scalefake "k8s.io/client-go/scale/fake"
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core "k8s.io/client-go/testing"
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"k8s.io/client-go/tools/cache"
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"k8s.io/client-go/util/workqueue"
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"k8s.io/klog"
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_ "k8s.io/kubernetes/pkg/apis/core/install"
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"k8s.io/kubernetes/pkg/controller"
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utilpointer "k8s.io/utils/pointer"
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@ -97,6 +105,7 @@ type disruptionController struct {
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dStore cache.Store
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ssStore cache.Store
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coreClient *fake.Clientset
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scaleClient *scalefake.FakeScaleClient
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}
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@ -109,7 +118,8 @@ var customGVK = schema.GroupVersionKind{
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func newFakeDisruptionController() (*disruptionController, *pdbStates) {
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ps := &pdbStates{}
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informerFactory := informers.NewSharedInformerFactory(nil, controller.NoResyncPeriodFunc())
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coreClient := fake.NewSimpleClientset()
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informerFactory := informers.NewSharedInformerFactory(coreClient, controller.NoResyncPeriodFunc())
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scheme := runtime.NewScheme()
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scheme.AddKnownTypeWithName(customGVK, &v1.Service{})
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@ -122,7 +132,7 @@ func newFakeDisruptionController() (*disruptionController, *pdbStates) {
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informerFactory.Apps().V1().ReplicaSets(),
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informerFactory.Apps().V1().Deployments(),
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informerFactory.Apps().V1().StatefulSets(),
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nil,
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coreClient,
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testrestmapper.TestOnlyStaticRESTMapper(scheme),
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fakeScaleClient,
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)
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@ -134,6 +144,9 @@ func newFakeDisruptionController() (*disruptionController, *pdbStates) {
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dc.dListerSynced = alwaysReady
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dc.ssListerSynced = alwaysReady
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informerFactory.Start(context.TODO().Done())
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informerFactory.WaitForCacheSync(nil)
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return &disruptionController{
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dc,
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informerFactory.Core().V1().Pods().Informer().GetStore(),
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@ -142,6 +155,7 @@ func newFakeDisruptionController() (*disruptionController, *pdbStates) {
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informerFactory.Apps().V1().ReplicaSets().Informer().GetStore(),
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informerFactory.Apps().V1().Deployments().Informer().GetStore(),
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informerFactory.Apps().V1().StatefulSets().Informer().GetStore(),
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coreClient,
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fakeScaleClient,
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}, ps
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}
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@ -1025,3 +1039,144 @@ func TestDeploymentFinderFunction(t *testing.T) {
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})
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}
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}
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// This test checks that the disruption controller does not write stale data to
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// a PDB status during race conditions with the eviction handler. Specifically,
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// failed updates due to ResourceVersion conflict should not cause a stale value
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// of PodDisruptionsAllowed to be written.
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//
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// In this test, PodDisruptionsAllowed starts at 2.
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// (A) We will delete 1 pod and trigger DisruptionController to set
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// PodDisruptionsAllowed to 1.
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// (B) As the DisruptionController attempts this write, we will evict the
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// remaining 2 pods and update PodDisruptionsAllowed to 0. (The real eviction
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// handler would allow this because it still sees PodDisruptionsAllowed=2.)
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// (C) If the DisruptionController writes PodDisruptionsAllowed=1 despite the
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// resource conflict error, then there is a bug.
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func TestUpdatePDBStatusRetries(t *testing.T) {
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dc, _ := newFakeDisruptionController()
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// Inject the production code over our fake impl
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dc.getUpdater = func() updater { return dc.writePdbStatus }
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// Create a PDB and 3 pods that match it.
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pdb, pdbKey := newMinAvailablePodDisruptionBudget(t, intstr.FromInt(1))
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pdb, err := dc.coreClient.PolicyV1beta1().PodDisruptionBudgets(pdb.Namespace).Create(pdb)
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if err != nil {
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t.Fatalf("Failed to create PDB: %v", err)
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}
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podNames := []string{"moe", "larry", "curly"}
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for _, name := range podNames {
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pod, _ := newPod(t, name)
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_, err := dc.coreClient.CoreV1().Pods(pod.Namespace).Create(pod)
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if err != nil {
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t.Fatalf("Failed to create pod: %v", err)
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}
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}
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// Block until the fake clientset writes are observable in the informer caches.
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// FUN FACT: This guarantees that the informer caches have updated, but it does
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// not guarantee that informer event handlers have completed. Fortunately,
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// DisruptionController does most of its logic by reading from informer
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// listers, so this guarantee is sufficient.
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if err := waitForCacheCount(dc.pdbStore, 1); err != nil {
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t.Fatalf("Failed to verify PDB in informer cache: %v", err)
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}
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if err := waitForCacheCount(dc.podStore, len(podNames)); err != nil {
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t.Fatalf("Failed to verify pods in informer cache: %v", err)
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}
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// Sync DisruptionController once to update PDB status.
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if err := dc.sync(pdbKey); err != nil {
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t.Fatalf("Failed initial sync: %v", err)
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}
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// Evict simulates the visible effects of eviction in our fake client.
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evict := func(podNames ...string) {
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// These GVRs are copied from the generated fake code because they are not exported.
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var (
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podsResource = schema.GroupVersionResource{Group: "", Version: "v1", Resource: "pods"}
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poddisruptionbudgetsResource = schema.GroupVersionResource{Group: "policy", Version: "v1beta1", Resource: "poddisruptionbudgets"}
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)
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// Bypass the coreClient.Fake and write directly to the ObjectTracker, because
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// this helper will be called while the Fake is holding a lock.
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obj, err := dc.coreClient.Tracker().Get(poddisruptionbudgetsResource, pdb.Namespace, pdb.Name)
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if err != nil {
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t.Fatalf("Failed to get PDB: %v", err)
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}
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updatedPDB := obj.(*policy.PodDisruptionBudget)
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// Each eviction,
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// - decrements PodDisruptionsAllowed
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// - adds the pod to DisruptedPods
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// - deletes the pod
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updatedPDB.Status.PodDisruptionsAllowed -= int32(len(podNames))
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updatedPDB.Status.DisruptedPods = make(map[string]metav1.Time)
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for _, name := range podNames {
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updatedPDB.Status.DisruptedPods[name] = metav1.NewTime(time.Now())
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}
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if err := dc.coreClient.Tracker().Update(poddisruptionbudgetsResource, updatedPDB, updatedPDB.Namespace); err != nil {
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t.Fatalf("Eviction (PDB update) failed: %v", err)
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}
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for _, name := range podNames {
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if err := dc.coreClient.Tracker().Delete(podsResource, "default", name); err != nil {
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t.Fatalf("Eviction (pod delete) failed: %v", err)
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}
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}
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}
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// The fake kube client does not update ResourceVersion or check for conflicts.
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// Instead, we add a reactor that returns a conflict error on the first PDB
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// update and success after that.
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var failOnce sync.Once
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dc.coreClient.Fake.PrependReactor("update", "poddisruptionbudgets", func(a core.Action) (handled bool, obj runtime.Object, err error) {
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failOnce.Do(func() {
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// (B) Evict two pods and fail this update.
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evict(podNames[1], podNames[2])
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handled = true
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err = errors.NewConflict(a.GetResource().GroupResource(), pdb.Name, fmt.Errorf("conflict"))
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})
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return handled, obj, err
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})
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// (A) Delete one pod
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if err := dc.coreClient.CoreV1().Pods("default").Delete(podNames[0], &metav1.DeleteOptions{}); err != nil {
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t.Fatal(err)
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}
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if err := waitForCacheCount(dc.podStore, len(podNames)-1); err != nil {
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t.Fatalf("Failed to verify pods in informer cache: %v", err)
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}
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// The sync() function should either write a correct status which takes the
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// evictions into account, or re-queue the PDB for another sync (by returning
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// an error)
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if err := dc.sync(pdbKey); err != nil {
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t.Logf("sync() returned with error: %v", err)
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} else {
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t.Logf("sync() returned with no error")
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}
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// (C) Whether or not sync() returned an error, the PDB status should reflect
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// the evictions that took place.
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finalPDB, err := dc.coreClient.PolicyV1beta1().PodDisruptionBudgets("default").Get(pdb.Name, metav1.GetOptions{})
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if err != nil {
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t.Fatalf("Failed to get PDB: %v", err)
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}
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if expected, actual := int32(0), finalPDB.Status.PodDisruptionsAllowed; expected != actual {
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t.Errorf("PodDisruptionsAllowed should be %d, got %d", expected, actual)
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}
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}
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// waitForCacheCount blocks until the given cache store has the desired number
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// of items in it. This will return an error if the condition is not met after a
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// 10 second timeout.
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func waitForCacheCount(store cache.Store, n int) error {
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return wait.Poll(10*time.Millisecond, 10*time.Second, func() (bool, error) {
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return len(store.List()) == n, nil
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})
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}
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// TestMain adds klog flags to make debugging tests easier.
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func TestMain(m *testing.M) {
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klog.InitFlags(flag.CommandLine)
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os.Exit(m.Run())
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}
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