func (e *quotaEvaluator) Evaluate(a admission.Attributes) error {
e.init.Do(func() {
go e.run()
})
// if we do not know how to evaluate use for this kind, just ignore
evaluators := e.registry.Evaluators()
evaluator, found := evaluators[a.GetKind().GroupKind()]
if !found {
return nil
}
// for this kind, check if the operation could mutate any quota resources
// if no resources tracked by quota are impacted, then just return
op := a.GetOperation()
if !evaluator.Handles(op) {
return nil
}
waiter := newAdmissionWaiter(a)
e.addWork(waiter)
// wait for completion or timeout
select {
case <-waiter.finished:
case <-time.After(10 * time.Second):
return fmt.Errorf("timeout")
}
return waiter.result
}
// Admit admits resources into cluster that do not violate any defined LimitRange in the namespace
func (l *limitRanger) Admit(a admission.Attributes) (err error) {
if !l.actions.SupportsAttributes(a) {
return nil
}
obj := a.GetObject()
name := "Unknown"
if obj != nil {
name, _ = meta.NewAccessor().Name(obj)
if len(name) == 0 {
name, _ = meta.NewAccessor().GenerateName(obj)
}
}
items, err := l.lister.LimitRanges(a.GetNamespace()).List(labels.Everything())
if err != nil {
return admission.NewForbidden(a, fmt.Errorf("unable to %s %v at this time because there was an error enforcing limit ranges", a.GetOperation(), a.GetResource()))
}
// if there are no items held in our indexer, check our live-lookup LRU, if that misses, do the live lookup to prime it.
if len(items) == 0 {
lruItemObj, ok := l.liveLookupCache.Get(a.GetNamespace())
if !ok || lruItemObj.(liveLookupEntry).expiry.Before(time.Now()) {
// TODO: If there are multiple operations at the same time and cache has just expired,
// this may cause multiple List operations being issued at the same time.
// If there is already in-flight List() for a given namespace, we should wait until
// it is finished and cache is updated instead of doing the same, also to avoid
// throttling - see #22422 for details.
liveList, err := l.client.Core().LimitRanges(a.GetNamespace()).List(api.ListOptions{})
if err != nil {
return admission.NewForbidden(a, err)
}
newEntry := liveLookupEntry{expiry: time.Now().Add(l.liveTTL)}
for i := range liveList.Items {
newEntry.items = append(newEntry.items, &liveList.Items[i])
}
l.liveLookupCache.Add(a.GetNamespace(), newEntry)
lruItemObj = newEntry
}
lruEntry := lruItemObj.(liveLookupEntry)
for i := range lruEntry.items {
items = append(items, lruEntry.items[i])
}
}
// ensure it meets each prescribed min/max
for i := range items {
limitRange := items[i]
if !l.actions.SupportsLimit(limitRange) {
continue
}
err = l.actions.Limit(limitRange, a.GetResource().Resource, a.GetObject())
if err != nil {
return admission.NewForbidden(a, err)
}
}
return nil
}
// checkRequest verifies that the request does not exceed any quota constraint. it returns a copy of quotas not yet persisted
// that capture what the usage would be if the request succeeded. It return an error if the is insufficient quota to satisfy the request
func (e *quotaEvaluator) checkRequest(quotas []api.ResourceQuota, a admission.Attributes) ([]api.ResourceQuota, error) {
namespace := a.GetNamespace()
evaluators := e.registry.Evaluators()
evaluator, found := evaluators[a.GetKind().GroupKind()]
if !found {
return quotas, nil
}
op := a.GetOperation()
if !evaluator.Handles(op) {
return quotas, nil
}
// find the set of quotas that are pertinent to this request
// reject if we match the quota, but usage is not calculated yet
// reject if the input object does not satisfy quota constraints
// if there are no pertinent quotas, we can just return
inputObject := a.GetObject()
interestingQuotaIndexes := []int{}
for i := range quotas {
resourceQuota := quotas[i]
match, err := evaluator.Matches(&resourceQuota, inputObject)
if err != nil {
return quotas, err
}
if !match {
continue
}
hardResources := quota.ResourceNames(resourceQuota.Status.Hard)
requiredResources := evaluator.MatchingResources(hardResources)
if err := evaluator.Constraints(requiredResources, inputObject); err != nil {
return nil, admission.NewForbidden(a, fmt.Errorf("failed quota: %s: %v", resourceQuota.Name, err))
}
if !hasUsageStats(&resourceQuota) {
return nil, admission.NewForbidden(a, fmt.Errorf("status unknown for quota: %s", resourceQuota.Name))
}
interestingQuotaIndexes = append(interestingQuotaIndexes, i)
}
if len(interestingQuotaIndexes) == 0 {
return quotas, nil
}
// Usage of some resources cannot be counted in isolation. For example, when
// the resource represents a number of unique references to external
// resource. In such a case an evaluator needs to process other objects in
// the same namespace which needs to be known.
if accessor, err := meta.Accessor(inputObject); namespace != "" && err == nil {
if accessor.GetNamespace() == "" {
accessor.SetNamespace(namespace)
}
}
// there is at least one quota that definitely matches our object
// as a result, we need to measure the usage of this object for quota
// on updates, we need to subtract the previous measured usage
// if usage shows no change, just return since it has no impact on quota
deltaUsage, err := evaluator.Usage(inputObject)
if err != nil {
return quotas, err
}
// ensure that usage for input object is never negative (this would mean a resource made a negative resource requirement)
if negativeUsage := quota.IsNegative(deltaUsage); len(negativeUsage) > 0 {
return nil, admission.NewForbidden(a, fmt.Errorf("quota usage is negative for resource(s): %s", prettyPrintResourceNames(negativeUsage)))
}
if admission.Update == op {
prevItem := a.GetOldObject()
if prevItem == nil {
return nil, admission.NewForbidden(a, fmt.Errorf("unable to get previous usage since prior version of object was not found"))
}
// if we can definitively determine that this is not a case of "create on update",
// then charge based on the delta. Otherwise, bill the maximum
metadata, err := meta.Accessor(prevItem)
if err == nil && len(metadata.GetResourceVersion()) > 0 {
prevUsage, innerErr := evaluator.Usage(prevItem)
if innerErr != nil {
return quotas, innerErr
}
deltaUsage = quota.Subtract(deltaUsage, prevUsage)
}
}
if quota.IsZero(deltaUsage) {
return quotas, nil
}
outQuotas, err := copyQuotas(quotas)
if err != nil {
return nil, err
}
for _, index := range interestingQuotaIndexes {
resourceQuota := outQuotas[index]
hardResources := quota.ResourceNames(resourceQuota.Status.Hard)
requestedUsage := quota.Mask(deltaUsage, hardResources)
newUsage := quota.Add(resourceQuota.Status.Used, requestedUsage)
maskedNewUsage := quota.Mask(newUsage, quota.ResourceNames(requestedUsage))
if allowed, exceeded := quota.LessThanOrEqual(maskedNewUsage, resourceQuota.Status.Hard); !allowed {
failedRequestedUsage := quota.Mask(requestedUsage, exceeded)
failedUsed := quota.Mask(resourceQuota.Status.Used, exceeded)
failedHard := quota.Mask(resourceQuota.Status.Hard, exceeded)
return nil, admission.NewForbidden(a,
fmt.Errorf("exceeded quota: %s, requested: %s, used: %s, limited: %s",
resourceQuota.Name,
prettyPrint(failedRequestedUsage),
prettyPrint(failedUsed),
prettyPrint(failedHard)))
}
// update to the new usage number
outQuotas[index].Status.Used = newUsage
}
return outQuotas, nil
}
func (l *lifecycle) Admit(a admission.Attributes) error {
// prevent deletion of immortal namespaces
if a.GetOperation() == admission.Delete && a.GetKind().GroupKind() == api.Kind("Namespace") && l.immortalNamespaces.Has(a.GetName()) {
return errors.NewForbidden(a.GetResource().GroupResource(), a.GetName(), fmt.Errorf("this namespace may not be deleted"))
}
// if we're here, then we've already passed authentication, so we're allowed to do what we're trying to do
// if we're here, then the API server has found a route, which means that if we have a non-empty namespace
// its a namespaced resource.
if len(a.GetNamespace()) == 0 || a.GetKind().GroupKind() == api.Kind("Namespace") {
// if a namespace is deleted, we want to prevent all further creates into it
// while it is undergoing termination. to reduce incidences where the cache
// is slow to update, we add the namespace into a force live lookup list to ensure
// we are not looking at stale state.
if a.GetOperation() == admission.Delete {
l.forceLiveLookupCache.Add(a.GetName(), true, forceLiveLookupTTL)
}
return nil
}
// we need to wait for our caches to warm
if !l.WaitForReady() {
return admission.NewForbidden(a, fmt.Errorf("not yet ready to handle request"))
}
var (
namespaceObj interface{}
exists bool
err error
)
key := makeNamespaceKey(a.GetNamespace())
namespaceObj, exists, err = l.namespaceInformer.GetStore().Get(key)
if err != nil {
return errors.NewInternalError(err)
}
if !exists && a.GetOperation() == admission.Create {
// give the cache time to observe the namespace before rejecting a create.
// this helps when creating a namespace and immediately creating objects within it.
time.Sleep(missingNamespaceWait)
namespaceObj, exists, err = l.namespaceInformer.GetStore().Get(key)
if err != nil {
return errors.NewInternalError(err)
}
if exists {
glog.V(4).Infof("found %s in cache after waiting", a.GetNamespace())
}
}
// forceLiveLookup if true will skip looking at local cache state and instead always make a live call to server.
forceLiveLookup := false
if _, ok := l.forceLiveLookupCache.Get(a.GetNamespace()); ok {
// we think the namespace was marked for deletion, but our current local cache says otherwise, we will force a live lookup.
forceLiveLookup = exists && namespaceObj.(*api.Namespace).Status.Phase == api.NamespaceActive
}
// refuse to operate on non-existent namespaces
if !exists || forceLiveLookup {
// as a last resort, make a call directly to storage
namespaceObj, err = l.client.Core().Namespaces().Get(a.GetNamespace(), metav1.GetOptions{})
if err != nil {
if errors.IsNotFound(err) {
return err
}
return errors.NewInternalError(err)
}
glog.V(4).Infof("found %s via storage lookup", a.GetNamespace())
}
// ensure that we're not trying to create objects in terminating namespaces
if a.GetOperation() == admission.Create {
namespace := namespaceObj.(*api.Namespace)
if namespace.Status.Phase != api.NamespaceTerminating {
return nil
}
// TODO: This should probably not be a 403
return admission.NewForbidden(a, fmt.Errorf("unable to create new content in namespace %s because it is being terminated.", a.GetNamespace()))
}
return nil
}