Merge pull request #118862 from byako/batching-dra-calls

DRA controller: batch resource claims for Allocate

staging/src/k8s.io/dynamic-resource-allocation/controller/controller.go

@@ -68,8 +68,8 @@ type Driver interface {
 	// The caller will wrap the error to include the parameter reference.
 	GetClaimParameters(ctx context.Context, claim *resourcev1alpha2.ResourceClaim, class *resourcev1alpha2.ResourceClass, classParameters interface{}) (interface{}, error)
 
-	// Allocate gets called when a ResourceClaim is ready to be allocated.
+	// Allocate gets called when all same-driver ResourceClaims for Pod are ready
-	// The selectedNode is empty for ResourceClaims with immediate
+	// to be allocated. The selectedNode is empty for ResourceClaims with immediate
 	// allocation, in which case the resource driver decides itself where
 	// to allocate. If there is already an on-going allocation, the driver
 	// may finish it and ignore the new parameters or abort the on-going
@@ -77,15 +77,21 @@ type Driver interface {
 	//
 	// Parameters have been retrieved earlier.
 	//
+	// Driver must set the result of allocation for every claim in "claims"
+	// parameter items. In case if there was no error encountered and allocation
+	// was successful - claims[i].Allocation field should be set. In case of
+	// particular claim allocation fail - respective item's claims[i].Error field
+	// should be set, in this case claims[i].Allocation will be ignored.
+	//
 	// If selectedNode is set, the driver must attempt to allocate for that
 	// node. If that is not possible, it must return an error. The
 	// controller will call UnsuitableNodes and pass the new information to
 	// the scheduler, which then will lead to selecting a diffent node
 	// if the current one is not suitable.
 	//
-	// The objects are read-only and must not be modified. This call
+	// The Claim, ClaimParameters, Class, ClassParameters fields of "claims" parameter
-	// must be idempotent.
+	// items are read-only and must not be modified. This call must be idempotent.
-	Allocate(ctx context.Context, claim *resourcev1alpha2.ResourceClaim, claimParameters interface{}, class *resourcev1alpha2.ResourceClass, classParameters interface{}, selectedNode string) (*resourcev1alpha2.AllocationResult, error)
+	Allocate(ctx context.Context, claims []*ClaimAllocation, selectedNode string)
 
 	// Deallocate gets called when a ResourceClaim is ready to be
 	// freed.
@@ -125,6 +131,13 @@ type ClaimAllocation struct {
 	// UnsuitableNodes needs to be filled in by the driver when
 	// Driver.UnsuitableNodes gets called.
 	UnsuitableNodes []string
+
+	// Driver must populate this field with resources that were
+	// allocated for the claim in case of successful allocation.
+	Allocation *resourcev1alpha2.AllocationResult
+	// In case of error allocating particular claim, driver must
+	// populate this field.
+	Error error
 }
 
 type controller struct {
@@ -500,7 +513,20 @@ func (ctrl *controller) syncClaim(ctx context.Context, claim *resourcev1alpha2.R
 		return err
 	}
 
-	return ctrl.allocateClaim(ctx, claim, claimParameters, class, classParameters, "", nil)
+	claimAllocations := claimAllocations{&ClaimAllocation{
+		Claim:           claim,
+		ClaimParameters: claimParameters,
+		Class:           class,
+		ClassParameters: classParameters,
+	}}
+
+	ctrl.allocateClaims(ctx, claimAllocations, "", nil)
+
+	if claimAllocations[0].Error != nil {
+		return fmt.Errorf("allocate: %v", claimAllocations[0].Error)
+	}
+
+	return nil
 }
 
 func (ctrl *controller) getParameters(ctx context.Context, claim *resourcev1alpha2.ResourceClaim, class *resourcev1alpha2.ResourceClass) (claimParameters, classParameters interface{}, err error) {
@@ -517,51 +543,85 @@ func (ctrl *controller) getParameters(ctx context.Context, claim *resourcev1alph
 	return
 }
 
-func (ctrl *controller) allocateClaim(ctx context.Context,
+// allocateClaims filters list of claims, keeps those needing allocation and asks driver to do the allocations.
-	claim *resourcev1alpha2.ResourceClaim, claimParameters interface{},
+// Driver is supposed to write the AllocationResult and Error field into argument claims slice.
-	class *resourcev1alpha2.ResourceClass, classParameters interface{},
+func (ctrl *controller) allocateClaims(ctx context.Context, claims []*ClaimAllocation, selectedNode string, selectedUser *resourcev1alpha2.ResourceClaimConsumerReference) {
-	selectedNode string,
-	selectedUser *resourcev1alpha2.ResourceClaimConsumerReference) error {
 	logger := klog.FromContext(ctx)
 
-	if claim.Status.Allocation != nil {
+	needAllocation := make([]*ClaimAllocation, 0, len(claims))
-		// This can happen when two PodSchedulingContext objects trigger
+	for _, claim := range claims {
-		// allocation attempts (first one wins) or when we see the
+		if claim.Claim.Status.Allocation != nil {
-		// update of the PodSchedulingContext object.
+			// This can happen when two PodSchedulingContext objects trigger
-		logger.V(5).Info("Claim already allocated, nothing to do")
+			// allocation attempts (first one wins) or when we see the
-		return nil
+			// update of the PodSchedulingContext object.
+			logger.V(5).Info("Claim is already allocated, skipping allocation", "claim", claim.PodClaimName)
+			continue
+		}
+		needAllocation = append(needAllocation, claim)
 	}
 
-	claim = claim.DeepCopy()
+	if len(needAllocation) == 0 {
-	if !ctrl.hasFinalizer(claim) {
+		logger.V(5).Info("No claims need allocation, nothing to do")
-		// Set finalizer before doing anything. We continue with the updated claim.
+		return
-		logger.V(5).Info("Adding finalizer")
-		claim.Finalizers = append(claim.Finalizers, ctrl.finalizer)
-		var err error
-		claim, err = ctrl.kubeClient.ResourceV1alpha2().ResourceClaims(claim.Namespace).Update(ctx, claim, metav1.UpdateOptions{})
-		if err != nil {
-			return fmt.Errorf("add finalizer: %v", err)
-		}
-		ctrl.claimCache.Mutation(claim)
 	}
 
+	// Keep separately claims that succeeded adding finalizers,
+	// they will be sent for Allocate to the driver.
+	claimsWithFinalizers := make([]*ClaimAllocation, 0, len(needAllocation))
+	for _, claimAllocation := range needAllocation {
+		if !ctrl.hasFinalizer(claimAllocation.Claim) {
+			claim := claimAllocation.Claim.DeepCopy()
+			// Set finalizer before doing anything. We continue with the updated claim.
+			logger.V(5).Info("Adding finalizer", "claim", claim.Name)
+			claim.Finalizers = append(claim.Finalizers, ctrl.finalizer)
+			var err error
+			claim, err = ctrl.kubeClient.ResourceV1alpha2().ResourceClaims(claim.Namespace).Update(ctx, claim, metav1.UpdateOptions{})
+			if err != nil {
+				logger.Error(err, "add finalizer", "claim", claim.Name)
+				claimAllocation.Error = fmt.Errorf("add finalizer: %v", err)
+				// Do not save claim to ask for Allocate from Driver.
+				continue
+			}
+			ctrl.claimCache.Mutation(claim)
+			claimAllocation.Claim = claim
+		}
+		claimsWithFinalizers = append(claimsWithFinalizers, claimAllocation)
+	}
+
+	// Beyond here we only operate with claimsWithFinalizers because those are ready for allocation.
+
 	logger.V(5).Info("Allocating")
-	allocation, err := ctrl.driver.Allocate(ctx, claim, claimParameters, class, classParameters, selectedNode)
+	ctrl.driver.Allocate(ctx, claimsWithFinalizers, selectedNode)
-	if err != nil {
+
-		return fmt.Errorf("allocate: %v", err)
+	// Update successfully allocated claims' status with allocation info.
+	for _, claimAllocation := range claimsWithFinalizers {
+		if claimAllocation.Error != nil {
+			logger.Error(claimAllocation.Error, "allocating claim", "claim", claimAllocation.Claim.Name)
+			continue
+		}
+		if claimAllocation.Allocation == nil {
+			logger.Error(nil, "allocating claim: missing allocation from driver", "claim", claimAllocation.Claim.Name)
+			claimAllocation.Error = fmt.Errorf("allocating claim: missing allocation from driver")
+			// Do not update this claim with allocation, it might succeed next time.
+			continue
+		}
+		logger.V(5).Info("successfully allocated", "claim", klog.KObj(claimAllocation.Claim))
+		claim := claimAllocation.Claim.DeepCopy()
+		claim.Status.Allocation = claimAllocation.Allocation
+		claim.Status.DriverName = ctrl.name
+		if selectedUser != nil {
+			claim.Status.ReservedFor = append(claim.Status.ReservedFor, *selectedUser)
+		}
+		logger.V(6).Info("Updating claim after allocation", "claim", claim)
+		claim, err := ctrl.kubeClient.ResourceV1alpha2().ResourceClaims(claim.Namespace).UpdateStatus(ctx, claim, metav1.UpdateOptions{})
+		if err != nil {
+			claimAllocation.Error = fmt.Errorf("add allocation: %v", err)
+			continue
+		}
+
+		ctrl.claimCache.Mutation(claim)
 	}
-	claim.Status.Allocation = allocation
+	return
-	claim.Status.DriverName = ctrl.name
-	if selectedUser != nil {
-		claim.Status.ReservedFor = append(claim.Status.ReservedFor, *selectedUser)
-	}
-	logger.V(6).Info("Updating claim after allocation", "claim", claim)
-	claim, err = ctrl.kubeClient.ResourceV1alpha2().ResourceClaims(claim.Namespace).UpdateStatus(ctx, claim, metav1.UpdateOptions{})
-	if err != nil {
-		return fmt.Errorf("add allocation: %v", err)
-	}
-	ctrl.claimCache.Mutation(claim)
-	return nil
 }
 
 func (ctrl *controller) checkPodClaim(ctx context.Context, pod *v1.Pod, podClaim v1.PodResourceClaim) (*ClaimAllocation, error) {
@@ -690,11 +750,20 @@ func (ctrl *controller) syncPodSchedulingContexts(ctx context.Context, schedulin
 				Name:     pod.Name,
 				UID:      pod.UID,
 			}
+
+			ctrl.allocateClaims(ctx, claims, selectedNode, selectedUser)
+
+			allErrorsStr := "allocation of one or more pod claims failed."
+			allocationFailed := false
 			for _, delayed := range claims {
-				if err := ctrl.allocateClaim(ctx, delayed.Claim, delayed.ClaimParameters, delayed.Class, delayed.ClassParameters, selectedNode, selectedUser); err != nil {
+				if delayed.Error != nil {
-					return fmt.Errorf("allocation of pod claim %s failed: %v", delayed.PodClaimName, err)
+					allErrorsStr = fmt.Sprintf("%s Claim %s: %s.", allErrorsStr, delayed.Claim.Name, delayed.Error)
+					allocationFailed = true
 				}
 			}
+			if allocationFailed {
+				return fmt.Errorf(allErrorsStr)
+			}
 		}
 	}
 

staging/src/k8s.io/dynamic-resource-allocation/controller/controller_test.go

@@ -533,14 +533,19 @@ func (m mockDriver) GetClaimParameters(ctx context.Context, claim *resourcev1alp
 	return result, nil
 }
 
-func (m mockDriver) Allocate(ctx context.Context, claim *resourcev1alpha2.ResourceClaim, claimParameters interface{}, class *resourcev1alpha2.ResourceClass, classParameters interface{}, selectedNode string) (*resourcev1alpha2.AllocationResult, error) {
+func (m mockDriver) Allocate(ctx context.Context, claims []*ClaimAllocation, selectedNode string) {
-	m.t.Logf("Allocate(%s)", claim)
+	m.t.Logf("Allocate(number of claims %d)", len(claims))
-	allocate, ok := m.allocate[claim.Name]
+	for _, claimAllocation := range claims {
-	if !ok {
+		m.t.Logf("Allocate(%s)", claimAllocation.Claim.Name)
-		m.t.Fatal("unexpected Allocate call")
+		allocate, ok := m.allocate[claimAllocation.Claim.Name]
+		if !ok {
+			m.t.Fatalf("unexpected Allocate call for claim %s", claimAllocation.Claim.Name)
+		}
+		assert.Equal(m.t, allocate.selectedNode, selectedNode, "selected node")
+		claimAllocation.Error = allocate.allocErr
+		claimAllocation.Allocation = allocate.allocResult
 	}
-	assert.Equal(m.t, allocate.selectedNode, selectedNode, "selected node")
+	return
-	return allocate.allocResult, allocate.allocErr
 }
 
 func (m mockDriver) Deallocate(ctx context.Context, claim *resourcev1alpha2.ResourceClaim) error {

test/e2e/dra/README.md

@@ -41,10 +41,10 @@ $ kind create cluster --config test/e2e/dra/kind.yaml --image dra/node:latest
 
 - Build ginkgo
 
-> NB: If you are using go workspace you must disable it `GOWORK=off make gingko`
+> NB: If you are using go workspace you must disable it `GOWORK=off make ginkgo`
 
 ```bash
-$ make gingko
+$ make ginkgo
 ```
 
 - Run e2e tests for the `Dynamic Resource Allocation` feature:

test/e2e/dra/dra.go

@@ -20,8 +20,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"strings"
-	"sync/atomic"
 	"time"
 
 	"github.com/onsi/ginkgo/v2"
@@ -32,6 +30,7 @@ import (
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/kubernetes"
+	"k8s.io/dynamic-resource-allocation/controller"
 	"k8s.io/klog/v2"
 	"k8s.io/kubernetes/test/e2e/dra/test-driver/app"
 	"k8s.io/kubernetes/test/e2e/framework"
@@ -427,69 +426,102 @@ var _ = ginkgo.Describe("[sig-node] DRA [Feature:DynamicResourceAllocation]", fu
 		})
 
 		ginkgo.Context("reallocation", func() {
-			var allocateWrapper app.AllocateWrapperType
+			var allocateWrapper2 app.AllocateWrapperType
 			driver := NewDriver(f, nodes, func() app.Resources {
+				return app.Resources{
+					NodeLocal:      true,
+					MaxAllocations: 2,
+					Nodes:          nodes.NodeNames,
+				}
+			})
+			driver2 := NewDriver(f, nodes, func() app.Resources {
 				return app.Resources{
 					NodeLocal:      true,
 					MaxAllocations: 2,
 					Nodes:          nodes.NodeNames,
 
-					AllocateWrapper: func(ctx context.Context, claim *resourcev1alpha2.ResourceClaim, claimParameters interface{}, class *resourcev1alpha2.ResourceClass, classParameters interface{}, selectedNode string,
+					AllocateWrapper: func(
-						handler func(ctx context.Context, claim *resourcev1alpha2.ResourceClaim, claimParameters interface{}, class *resourcev1alpha2.ResourceClass, classParameters interface{}, selectedNode string) (result *resourcev1alpha2.AllocationResult, err error)) (result *resourcev1alpha2.AllocationResult, err error) {
+						ctx context.Context,
-						return allocateWrapper(ctx, claim, claimParameters, class, classParameters, selectedNode, handler)
+						claimAllocations []*controller.ClaimAllocation,
+						selectedNode string,
+						handler func(
+							ctx context.Context,
+							claimAllocations []*controller.ClaimAllocation,
+							selectedNode string),
+					) {
+						allocateWrapper2(ctx, claimAllocations, selectedNode, handler)
+						return
 					},
 				}
 			})
+			driver2.NameSuffix = "-other"
+
 			b := newBuilder(f, driver)
+			b2 := newBuilder(f, driver2)
 
 			ginkgo.It("works", func(ctx context.Context) {
-				// A pod with two claims can run on a node, but
+				// A pod with multiple claims can run on a node, but
-				// only if allocation of both succeeds. This
+				// only if allocation of all succeeds. This
-				// tests simulates the scenario where one claim
+				// test simulates the scenario where one claim
-				// gets allocated but the second doesn't
+				// gets allocated from one driver, but the claims
-				// because of a race with some other pod.
+				// from second driver fail allocation because of a
+				// race with some other pod.
 				//
-				// To ensure the right timing, allocation of the second
+				// To ensure the right timing, allocation of the
-				// claim gets delayed while creating another pod
+				// claims from second driver are delayed while
-				// that gets the remaining resource on the node.
+				// creating another pod that gets the remaining
+				// resource on the node from second driver.
 				ctx, cancel := context.WithCancel(ctx)
 				defer cancel()
 
-				parameters := b.parameters()
+				parameters1 := b.parameters()
-				claim1 := b.externalClaim(resourcev1alpha2.AllocationModeWaitForFirstConsumer)
+				parameters2 := b2.parameters()
-				claim2 := b.externalClaim(resourcev1alpha2.AllocationModeWaitForFirstConsumer)
 				pod1 := b.podExternal()
+				pod2 := b2.podExternal()
+				pod1claim1 := b.externalClaim(resourcev1alpha2.AllocationModeWaitForFirstConsumer)
+				pod2claim1 := b2.externalClaim(resourcev1alpha2.AllocationModeWaitForFirstConsumer)
+				pod1claim2 := b2.externalClaim(resourcev1alpha2.AllocationModeWaitForFirstConsumer)
+				pod1claim3 := b2.externalClaim(resourcev1alpha2.AllocationModeWaitForFirstConsumer)
+
 				pod1.Spec.ResourceClaims = append(pod1.Spec.ResourceClaims,
 					v1.PodResourceClaim{
-						Name: "claim2",
+						Name: "claim-other1",
 						Source: v1.ClaimSource{
-							ResourceClaimName: &claim2.Name,
+							ResourceClaimName: &pod1claim2.Name,
+						},
+					},
+					v1.PodResourceClaim{
+						Name: "claim-other2",
+						Source: v1.ClaimSource{
+							ResourceClaimName: &pod1claim3.Name,
 						},
 					},
 				)
 
-				// Block on the second external claim that is to be allocated.
+				// Block on the second, third external claim from driver2 that is to be allocated.
 				blockClaim, cancelBlockClaim := context.WithCancel(ctx)
 				defer cancelBlockClaim()
-				var allocated int32
+
-				allocateWrapper = func(ctx context.Context, claim *resourcev1alpha2.ResourceClaim, claimParameters interface{},
+				b2.create(ctx, parameters2, pod1claim2, pod1claim3)
-					class *resourcev1alpha2.ResourceClass, classParameters interface{}, selectedNode string,
+				b.create(ctx, parameters1, pod1claim1, pod1)
-					handler func(ctx context.Context, claim *resourcev1alpha2.ResourceClaim, claimParameters interface{},
+
-						class *resourcev1alpha2.ResourceClass, classParameters interface{}, selectedNode string) (result *resourcev1alpha2.AllocationResult, err error),
+				allocateWrapper2 = func(ctx context.Context,
-				) (result *resourcev1alpha2.AllocationResult, err error) {
+					claimAllocations []*controller.ClaimAllocation,
-					oldAllocated := atomic.AddInt32(&allocated, 0)
+					selectedNode string,
-					if oldAllocated == 1 && strings.HasPrefix(claim.Name, "external-claim") {
+					handler func(ctx context.Context,
+						claimAllocations []*controller.ClaimAllocation,
+						selectedNode string),
+				) {
+					// pod1 will have only external-claim[2-3], it has to wait
+					// for pod2 to consume resources from driver2
+					if claimAllocations[0].Claim.Name != "external-claim-other" {
 						<-blockClaim.Done()
 					}
-					result, err = handler(ctx, claim, claimParameters, class, classParameters, selectedNode)
+					handler(ctx, claimAllocations, selectedNode)
-					if err == nil {
-						atomic.AddInt32(&allocated, 1)
-					}
 					return
 				}
-				b.create(ctx, parameters, claim1, claim2, pod1)
 
-				ginkgo.By("waiting for one claim to be allocated")
+				ginkgo.By("waiting for one claim from driver1 to be allocated")
 				var nodeSelector *v1.NodeSelector
 				gomega.Eventually(ctx, func(ctx context.Context) (int, error) {
 					claims, err := f.ClientSet.ResourceV1alpha2().ResourceClaims(f.Namespace.Name).List(ctx, metav1.ListOptions{})
@@ -512,18 +544,20 @@ var _ = ginkgo.Describe("[sig-node] DRA [Feature:DynamicResourceAllocation]", fu
 				// the node selector looks like and can
 				// directly access the key and value from it.
 				ginkgo.By(fmt.Sprintf("create second pod on the same node %s", nodeSelector))
-				pod2, template2 := b.podInline(resourcev1alpha2.AllocationModeWaitForFirstConsumer)
+
 				req := nodeSelector.NodeSelectorTerms[0].MatchExpressions[0]
 				node := req.Values[0]
 				pod2.Spec.NodeSelector = map[string]string{req.Key: node}
-				b.create(ctx, pod2, template2)
+
+				b2.create(ctx, pod2claim1, pod2)
 				framework.ExpectNoError(e2epod.WaitForPodRunningInNamespace(ctx, f.ClientSet, pod2), "start pod 2")
 
-				// Allow allocation of claim2 to proceed. It should fail now
+				// Allow allocation of pod1 claim2, claim3 to proceed. It should fail now
 				// and the other node must be used instead, after deallocating
 				// the first claim.
 				ginkgo.By("move first pod to other node")
 				cancelBlockClaim()
+
 				framework.ExpectNoError(e2epod.WaitForPodRunningInNamespace(ctx, f.ClientSet, pod1), "start pod 1")
 				pod1, err := f.ClientSet.CoreV1().Pods(pod1.Namespace).Get(ctx, pod1.Name, metav1.GetOptions{})
 				framework.ExpectNoError(err, "get first pod")
@@ -546,6 +580,7 @@ var _ = ginkgo.Describe("[sig-node] DRA [Feature:DynamicResourceAllocation]", fu
 			}
 		})
 		b1 := newBuilder(f, driver1)
+
 		driver2 := NewDriver(f, nodes, func() app.Resources {
 			return app.Resources{
 				NodeLocal:      true,

test/e2e/dra/test-driver/app/controller.go

@@ -47,11 +47,12 @@ type Resources struct {
 	AllocateWrapper AllocateWrapperType
 }
 
-type AllocateWrapperType func(ctx context.Context, claim *resourcev1alpha2.ResourceClaim, claimParameters interface{},
+type AllocateWrapperType func(ctx context.Context, claimAllocations []*controller.ClaimAllocation,
-	class *resourcev1alpha2.ResourceClass, classParameters interface{}, selectedNode string,
+	selectedNode string,
-	handler func(ctx context.Context, claim *resourcev1alpha2.ResourceClaim, claimParameters interface{},
+	handler func(ctx context.Context,
-		class *resourcev1alpha2.ResourceClass, classParameters interface{}, selectedNode string) (result *resourcev1alpha2.AllocationResult, err error),
+		claimAllocations []*controller.ClaimAllocation,
-) (result *resourcev1alpha2.AllocationResult, err error)
+		selectedNode string),
+)
 
 type ExampleController struct {
 	clientset  kubernetes.Interface
@@ -152,15 +153,30 @@ func (c *ExampleController) readParametersFromConfigMap(ctx context.Context, nam
 	return configMap.Data, nil
 }
 
-func (c *ExampleController) Allocate(ctx context.Context, claim *resourcev1alpha2.ResourceClaim, claimParameters interface{}, class *resourcev1alpha2.ResourceClass, classParameters interface{}, selectedNode string) (result *resourcev1alpha2.AllocationResult, err error) {
+func (c *ExampleController) Allocate(ctx context.Context, claimAllocations []*controller.ClaimAllocation, selectedNode string) {
+
 	if c.resources.AllocateWrapper != nil {
-		return c.resources.AllocateWrapper(ctx, claim, claimParameters, class, classParameters, selectedNode, c.allocate)
+		c.resources.AllocateWrapper(ctx, claimAllocations, selectedNode, c.allocateOneByOne)
+	} else {
+		c.allocateOneByOne(ctx, claimAllocations, selectedNode)
+	}
+
+	return
+}
+
+func (c *ExampleController) allocateOneByOne(ctx context.Context, claimAllocations []*controller.ClaimAllocation, selectedNode string) {
+	for _, ca := range claimAllocations {
+		allocationResult, err := c.allocateOne(ctx, ca.Claim, ca.ClaimParameters, ca.Class, ca.ClassParameters, selectedNode)
+		if err != nil {
+			ca.Error = fmt.Errorf("failed allocating claim %v", ca.Claim.UID)
+			continue
+		}
+		ca.Allocation = allocationResult
 	}
-	return c.allocate(ctx, claim, claimParameters, class, classParameters, selectedNode)
 }
 
 // allocate simply copies parameters as JSON map into a ResourceHandle.
-func (c *ExampleController) allocate(ctx context.Context, claim *resourcev1alpha2.ResourceClaim, claimParameters interface{}, class *resourcev1alpha2.ResourceClass, classParameters interface{}, selectedNode string) (result *resourcev1alpha2.AllocationResult, err error) {
+func (c *ExampleController) allocateOne(ctx context.Context, claim *resourcev1alpha2.ResourceClaim, claimParameters interface{}, class *resourcev1alpha2.ResourceClass, classParameters interface{}, selectedNode string) (result *resourcev1alpha2.AllocationResult, err error) {
 	logger := klog.LoggerWithValues(klog.LoggerWithName(klog.FromContext(ctx), "Allocate"), "claim", klog.KObj(claim), "uid", claim.UID)
 	defer func() {
 		logger.V(3).Info("done", "result", result, "err", err)