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Switch GC absentOwnerCache to full reference

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Before deleting an object based on absent owners, GC verifies absence of those owners with a live lookup.

The coordinates used to perform that live lookup are the ones specified in the ownerReference of the child.

In order to performantly delete multiple children from the same parent (e.g. 1000 pods from a replicaset),
a 404 response to a lookup is cached in absentOwnerCache.

Previously, the cache was a simple uid set. However, since children can disagree on the coordinates
that should be used to look up a given uid, the cache should record the exact coordinates verified absent.
This is a [apiVersion, kind, namespace, name, uid] tuple.
This commit is contained in:
Jordan Liggitt
2020-06-26 20:48:21 -04:00
parent 14f7f3201f
commit 445f20dbdb
6 changed files with 61 additions and 24 deletions
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23
pkg/controller/garbagecollector/garbagecollector.go
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@@ -72,7 +72,7 @@ type GarbageCollector struct {
attemptToOrphan workqueue.RateLimitingInterface
dependencyGraphBuilder *GraphBuilder
// GC caches the owners that do not exist according to the API server.
absentOwnerCache *UIDCache
absentOwnerCache *ReferenceCache
workerLock sync.RWMutex
}
@@ -94,7 +94,7 @@ func NewGarbageCollector(
attemptToDelete := workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "garbage_collector_attempt_to_delete")
attemptToOrphan := workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "garbage_collector_attempt_to_orphan")
absentOwnerCache := NewUIDCache(500)
absentOwnerCache := NewReferenceCache(500)
gc := &GarbageCollector{
metadataClient: metadataClient,
restMapper: mapper,
@@ -338,10 +338,20 @@ func (gc *GarbageCollector) attemptToDeleteWorker() bool {
// returns its latest state.
func (gc *GarbageCollector) isDangling(reference metav1.OwnerReference, item *node) (
dangling bool, owner *metav1.PartialObjectMetadata, err error) {
if gc.absentOwnerCache.Has(reference.UID) {
// check for recorded absent cluster-scoped parent
absentOwnerCacheKey := objectReference{OwnerReference: ownerReferenceCoordinates(reference)}
if gc.absentOwnerCache.Has(absentOwnerCacheKey) {
klog.V(5).Infof("according to the absentOwnerCache, object %s's owner %s/%s, %s does not exist", item.identity.UID, reference.APIVersion, reference.Kind, reference.Name)
return true, nil, nil
}
// check for recorded absent namespaced parent
absentOwnerCacheKey.Namespace = item.identity.Namespace
if gc.absentOwnerCache.Has(absentOwnerCacheKey) {
klog.V(5).Infof("according to the absentOwnerCache, object %s's owner %s/%s, %s does not exist in namespace %s", item.identity.UID, reference.APIVersion, reference.Kind, reference.Name, item.identity.Namespace)
return true, nil, nil
}
// TODO: we need to verify the reference resource is supported by the
// system. If it's not a valid resource, the garbage collector should i)
// ignore the reference when decide if the object should be deleted, and
@@ -352,6 +362,9 @@ func (gc *GarbageCollector) isDangling(reference metav1.OwnerReference, item *no
if err != nil {
return false, nil, err
}
if !namespaced {
absentOwnerCacheKey.Namespace = ""
}
// TODO: It's only necessary to talk to the API server if the owner node
// is a "virtual" node. The local graph could lag behind the real
@@ -359,7 +372,7 @@ func (gc *GarbageCollector) isDangling(reference metav1.OwnerReference, item *no
owner, err = gc.metadataClient.Resource(resource).Namespace(resourceDefaultNamespace(namespaced, item.identity.Namespace)).Get(context.TODO(), reference.Name, metav1.GetOptions{})
switch {
case errors.IsNotFound(err):
gc.absentOwnerCache.Add(reference.UID)
gc.absentOwnerCache.Add(absentOwnerCacheKey)
klog.V(5).Infof("object %s's owner %s/%s, %s is not found", item.identity.UID, reference.APIVersion, reference.Kind, reference.Name)
return true, nil, nil
case err != nil:
@@ -368,7 +381,7 @@ func (gc *GarbageCollector) isDangling(reference metav1.OwnerReference, item *no
if owner.GetUID() != reference.UID {
klog.V(5).Infof("object %s's owner %s/%s, %s is not found, UID mismatch", item.identity.UID, reference.APIVersion, reference.Kind, reference.Name)
gc.absentOwnerCache.Add(reference.UID)
gc.absentOwnerCache.Add(absentOwnerCacheKey)
return true, nil, nil
}
return false, owner, nil