feat: scheduler (10/): add more scheduler framework logic

apis/placement/v1beta1/binding_types.go

@@ -40,6 +40,9 @@ type ResourceBindingSpec struct {
 
 	// TargetCluster is the name of the cluster that the scheduler assigns the resources to.
 	TargetCluster string `json:"targetCluster"`
+
+	// ClusterDecision explains why the scheduler makes this binding.
+	ClusterDecision ClusterDecision `json:"clusterDecision"`
 }
 
 // ResourceBindingStatus represents the current status of a ClusterResourceBinding.

apis/placement/v1beta1/policysnapshot_types.go

@@ -16,6 +16,11 @@ const (
 
 	// PolicySnapshotNameFmt is clusterPolicySnapshot name format: {CRPName}-{PolicySnapshotIndex}.
 	PolicySnapshotNameFmt = "%s-%d"
+
+	// NumOfClustersAnnotation is an annotation that indicates the desired number of clusters where
+	// the selected resources should be placed. It is annotated on policy snapshots and is sync'd
+	// from the CRP to the currently active policy snapshot.
+	NumOfClustersAnnotation = fleetPrefix + "numOfClusters"
 )
 
 // +genclient

config/crd/bases/placement.karavel.io_clusterresourcebindings.yaml

@@ -47,6 +47,48 @@ spec:
           spec:
             description: The desired state of ClusterResourceBinding.
             properties:
+              clusterDecision:
+                description: ClusterDecision explains why the scheduler makes this
+                  binding.
+                properties:
+                  clusterName:
+                    description: ClusterName is the name of the ManagedCluster. If
+                      it is not empty, its value should be unique cross all placement
+                      decisions for the Placement.
+                    type: string
+                  clusterScore:
+                    description: ClusterScore represents the score of the cluster
+                      calculated by the scheduler.
+                    properties:
+                      affinityScore:
+                        description: AffinityScore represents the affinity score of
+                          the cluster calculated by the last scheduling decision based
+                          on the preferred affinity selector. An affinity score may
+                          not present if the cluster does not meet the required affinity.
+                        format: int32
+                        type: integer
+                      priorityScore:
+                        description: TopologySpreadScore represents the priority score
+                          of the cluster calculated by the last scheduling decision
+                          based on the topology spread applied to the cluster. A priority
+                          score may not present if the cluster does not meet the topology
+                          spread.
+                        format: int32
+                        type: integer
+                    type: object
+                  reason:
+                    description: Reason represents the reason why the cluster is selected
+                      or not.
+                    type: string
+                  selected:
+                    description: Selected indicates if this cluster is selected by
+                      the scheduler.
+                    type: boolean
+                required:
+                - clusterName
+                - reason
+                - selected
+                type: object
               resourceSnapshotName:
                 description: ResourceSnapshotName is the name of the resource snapshot
                   that this resource binding points to. If the resources are divided
@@ -58,6 +100,7 @@ spec:
                   assigns the resources to.
                 type: string
             required:
+            - clusterDecision
             - resourceSnapshotName
             - targetCluster
             type: object

pkg/scheduler/framework/cyclestate.go

@@ -8,6 +8,8 @@ package framework
 import (
 	"fmt"
 	"sync"
+
+	"k8s.io/apimachinery/pkg/util/sets"
 )
 
 // StateKey is the key for a state value stored in a CycleState.
@@ -32,6 +34,14 @@ type CycleStatePluginReadWriter interface {
 type CycleState struct {
 	// store is a concurrency-safe store (a map).
 	store sync.Map
+
+	// skippedFilterPlugins is a set of Filter plugins that should be skipped in the current scheduling cycle.
+	skippedFilterPlugins sets.String
+	// desiredBatchSize is the desired batch size for the current scheduling cycle.
+	desiredBatchSize int
+	// batchSizeLimit is the limit on batch size for the current scheduling cycle, set by
+	// post-batch plugins.
+	batchSizeLimit int
 }
 
 // Read retrieves a value from CycleState by a key.
@@ -54,5 +64,8 @@ func (c *CycleState) Delete(key StateKey) {
 
 // NewCycleState creates a CycleState.
 func NewCycleState() *CycleState {
-	return &CycleState{}
+	return &CycleState{
+		store:                sync.Map{},
+		skippedFilterPlugins: sets.NewString(),
+	}
 }

pkg/scheduler/framework/dummyplugins_test.go

@@ -0,0 +1,112 @@
+/*
+Copyright (c) Microsoft Corporation.
+Licensed under the MIT license.
+*/
+
+package framework
+
+import (
+	"context"
+
+	fleetv1beta1 "go.goms.io/fleet/apis/placement/v1beta1"
+)
+
+const (
+	dummyAllPurposePluginName      = "dummyAllPurposePlugin"
+	dummyPostBatchPluginNameFormat = "dummyPostBatchPlugin-%d"
+	dummyPreFilterPluginNameFormat = "dummyPreFilterPlugin-%d"
+	dummyFilterPluginNameFormat    = "dummyFilterPlugin-%d"
+)
+
+// A no-op, dummy plugin which connects to all extension points.
+type DummyAllPurposePlugin struct{}
+
+// Name returns the name of the dummy plugin.
+func (p *DummyAllPurposePlugin) Name() string {
+	return dummyAllPurposePluginName
+}
+
+// PostBatch implements the PostBatch interface for the dummy plugin.
+func (p *DummyAllPurposePlugin) PostBatch(ctx context.Context, state CycleStatePluginReadWriter, policy *fleetv1beta1.ClusterPolicySnapshot) (size int, status *Status) { //nolint:revive
+	return 1, nil
+}
+
+// PreFilter implements the PreFilter interface for the dummy plugin.
+func (p *DummyAllPurposePlugin) PreFilter(ctx context.Context, state CycleStatePluginReadWriter, policy *fleetv1beta1.ClusterPolicySnapshot) (status *Status) { //nolint:revive
+	return nil
+}
+
+// Filter implements the Filter interface for the dummy plugin.
+func (p *DummyAllPurposePlugin) Filter(ctx context.Context, state CycleStatePluginReadWriter, policy *fleetv1beta1.ClusterPolicySnapshot, cluster *fleetv1beta1.MemberCluster) (status *Status) { //nolint:revive
+	return nil
+}
+
+// PreScore implements the PreScore interface for the dummy plugin.
+func (p *DummyAllPurposePlugin) PreScore(ctx context.Context, state CycleStatePluginReadWriter, policy *fleetv1beta1.ClusterPolicySnapshot) (status *Status) { //nolint:revive
+	return nil
+}
+
+// Score implements the Score interface for the dummy plugin.
+func (p *DummyAllPurposePlugin) Score(ctx context.Context, state CycleStatePluginReadWriter, policy *fleetv1beta1.ClusterPolicySnapshot, cluster *fleetv1beta1.MemberCluster) (score *ClusterScore, status *Status) { //nolint:revive
+	return &ClusterScore{}, nil
+}
+
+// SetUpWithFramework is a no-op to satisfy the Plugin interface.
+func (p *DummyAllPurposePlugin) SetUpWithFramework(handle Handle) {} // nolint:revive
+
+// A dummy post batch plugin.
+type dummyPostBatchPlugin struct {
+	name   string
+	runner func(ctx context.Context, state CycleStatePluginReadWriter, policy *fleetv1beta1.ClusterPolicySnapshot) (size int, status *Status)
+}
+
+// Name returns the name of the dummy plugin.
+func (p *dummyPostBatchPlugin) Name() string {
+	return p.name
+}
+
+// PostBatch implements the PostBatch interface for the dummy plugin.
+func (p *dummyPostBatchPlugin) PostBatch(ctx context.Context, state CycleStatePluginReadWriter, policy *fleetv1beta1.ClusterPolicySnapshot) (size int, status *Status) { //nolint:revive
+	return p.runner(ctx, state, policy)
+}
+
+// SetUpWithFramework is a no-op to satisfy the Plugin interface.
+func (p *dummyPostBatchPlugin) SetUpWithFramework(handle Handle) {} // nolint:revive
+
+// A dummy pre-filter plugin.
+type dummyPreFilterPlugin struct {
+	name   string
+	runner func(ctx context.Context, state CycleStatePluginReadWriter, policy *fleetv1beta1.ClusterPolicySnapshot) (status *Status)
+}
+
+// Name returns the name of the dummy plugin.
+func (p *dummyPreFilterPlugin) Name() string {
+	return p.name
+}
+
+// PreFilter implements the PreFilter interface for the dummy plugin.
+func (p *dummyPreFilterPlugin) PreFilter(ctx context.Context, state CycleStatePluginReadWriter, policy *fleetv1beta1.ClusterPolicySnapshot) (status *Status) { //nolint:revive
+	return p.runner(ctx, state, policy)
+}
+
+// SetUpWithFramework is a no-op to satisfy the Plugin interface.
+func (p *dummyPreFilterPlugin) SetUpWithFramework(handle Handle) {} // nolint:revive
+
+// A dummy filter plugin.
+type dummyFilterPlugin struct {
+	name   string
+	runner func(ctx context.Context, state CycleStatePluginReadWriter, policy *fleetv1beta1.ClusterPolicySnapshot, cluster *fleetv1beta1.MemberCluster) (status *Status)
+}
+
+// Name returns the name of the dummy plugin.
+func (d *dummyFilterPlugin) Name() string {
+	return d.name
+}
+
+// Filter implements the Filter interface for the dummy plugin.
+func (d *dummyFilterPlugin) Filter(ctx context.Context, state CycleStatePluginReadWriter, policy *fleetv1beta1.ClusterPolicySnapshot, cluster *fleetv1beta1.MemberCluster) (status *Status) { //nolint:revive
+	return d.runner(ctx, state, policy, cluster)
+}
+
+// SetUpWithFramework is a no-op to satisfy the Plugin interface.
+func (p *dummyFilterPlugin) SetUpWithFramework(handle Handle) {} // nolint: revive