[TRB-54994]: Fixed a few issues that could cause resize actions to fa…

…il in namespaces with a LimitRange. (turbonomic#91)

* [TRB-54994]: Fixed a few issues that could cause resize actions to fail in namespaces with a LimitRange.

* Added comments indicating that we have updated code taken from upstream Kubernetes.

pkg/action/executor/limitrange_util.go

@@ -155,16 +155,18 @@ func PodValidateLimitFunc(limitRange *corev1.LimitRange, pod *corev1.Pod) error
 	return utilerrors.NewAggregate(errs)
 }
 
+// ===========================================================================
+// NOTE: This method has deviated from the upstream kubernetes code.
+// If we ever pull the latest changes from upstream, we may need to manually
+// update this method.
+// ===========================================================================
 // minConstraint enforces the min constraint over the specified resource
 func minConstraint(limitType string, resourceName string, enforced resource.Quantity, request corev1.ResourceList, limit corev1.ResourceList) error {
 	req, reqExists := request[corev1.ResourceName(resourceName)]
 	lim, limExists := limit[corev1.ResourceName(resourceName)]
 	observedReqValue, observedLimValue, enforcedValue := requestLimitEnforcedValues(req, lim, enforced)
 
-	if !reqExists {
-		return fmt.Errorf("minimum %s usage per %s is %s.  No request is specified", resourceName, limitType, enforced.String())
-	}
-	if observedReqValue < enforcedValue {
+	if reqExists && observedReqValue < enforcedValue {
 		return fmt.Errorf("minimum %s usage per %s is %s, but request is %s", resourceName, limitType, enforced.String(), req.String())
 	}
 	if limExists && (observedLimValue < enforcedValue) {
@@ -173,16 +175,18 @@ func minConstraint(limitType string, resourceName string, enforced resource.Quan
 	return nil
 }
 
+// ===========================================================================
+// NOTE: This method has deviated from the upstream kubernetes code.
+// If we ever pull the latest changes from upstream, we may need to manually
+// update this method.
+// ===========================================================================
 // maxConstraint enforces the max constraint over the specified resource
 func maxConstraint(limitType string, resourceName string, enforced resource.Quantity, request corev1.ResourceList, limit corev1.ResourceList) error {
 	req, reqExists := request[corev1.ResourceName(resourceName)]
 	lim, limExists := limit[corev1.ResourceName(resourceName)]
 	observedReqValue, observedLimValue, enforcedValue := requestLimitEnforcedValues(req, lim, enforced)
 
-	if !limExists {
-		return fmt.Errorf("maximum %s usage per %s is %s.  No limit is specified", resourceName, limitType, enforced.String())
-	}
-	if observedLimValue > enforcedValue {
+	if limExists && observedLimValue > enforcedValue {
 		return fmt.Errorf("maximum %s usage per %s is %s, but limit is %s", resourceName, limitType, enforced.String(), lim.String())
 	}
 	if reqExists && (observedReqValue > enforcedValue) {
@@ -315,24 +319,27 @@ func mergePodResourceRequirements(pod *corev1.Pod, defaultRequirements *corev1.R
 	}
 }
 
+// ===========================================================================
+// NOTE: This method has deviated from the upstream kubernetes code.
+// If we ever pull the latest changes from upstream, we may need to manually
+// update this method.
+// ===========================================================================
 // mergeContainerResources handles defaulting all of the resources on a container.
 func mergeContainerResources(container *corev1.Container, defaultRequirements *corev1.ResourceRequirements) {
-	if container.Resources.Limits == nil {
-		container.Resources.Limits = corev1.ResourceList{}
-	}
-	if container.Resources.Requests == nil {
-		container.Resources.Requests = corev1.ResourceList{}
-	}
-	for k, v := range defaultRequirements.Limits {
-		_, found := container.Resources.Limits[k]
-		if !found {
-			container.Resources.Limits[k] = v.DeepCopy()
+	if container.Resources.Limits != nil && len(container.Resources.Limits) > 0 {
+		for k, v := range defaultRequirements.Limits {
+			_, found := container.Resources.Limits[k]
+			if !found {
+				container.Resources.Limits[k] = v.DeepCopy()
+			}
 		}
 	}
-	for k, v := range defaultRequirements.Requests {
-		_, found := container.Resources.Requests[k]
-		if !found {
-			container.Resources.Requests[k] = v.DeepCopy()
+	if container.Resources.Requests != nil && len(container.Resources.Requests) > 0 {
+		for k, v := range defaultRequirements.Requests {
+			_, found := container.Resources.Requests[k]
+			if !found {
+				container.Resources.Requests[k] = v.DeepCopy()
+			}
 		}
 	}
 }

pkg/action/executor/workload_controller_resizer.go

@@ -310,16 +310,16 @@ func buildDesiredPod4QuotaEvaluation(namespace string, resizeSpecs []*containerR
 		if len(spec.NewCapacity) > 0 && len(podSpec.Containers[spec.Index].Resources.Limits) == 0 {
 			podSpec.Containers[spec.Index].Resources.Limits = make(k8sapi.ResourceList)
 		}
-		if newVal, found := spec.NewRequest[k8sapi.ResourceCPU]; found {
+		if newVal, found := spec.NewRequest[k8sapi.ResourceCPU]; found && !newVal.IsZero() {
 			podSpec.Containers[spec.Index].Resources.Requests[k8sapi.ResourceCPU] = newVal
 		}
-		if newVal, found := spec.NewRequest[k8sapi.ResourceMemory]; found {
+		if newVal, found := spec.NewRequest[k8sapi.ResourceMemory]; found && !newVal.IsZero() {
 			podSpec.Containers[spec.Index].Resources.Requests[k8sapi.ResourceMemory] = newVal
 		}
-		if newVal, found := spec.NewCapacity[k8sapi.ResourceCPU]; found {
+		if newVal, found := spec.NewCapacity[k8sapi.ResourceCPU]; found && !newVal.IsZero() {
 			podSpec.Containers[spec.Index].Resources.Limits[k8sapi.ResourceCPU] = newVal
 		}
-		if newVal, found := spec.NewCapacity[k8sapi.ResourceMemory]; found {
+		if newVal, found := spec.NewCapacity[k8sapi.ResourceMemory]; found && !newVal.IsZero() {
 			podSpec.Containers[spec.Index].Resources.Limits[k8sapi.ResourceMemory] = newVal
 		}
 	}