Add support for a centralized controller to advertise IMEX channel

Signed-off-by: Kevin Klues <[email protected]>

.gitignore

@@ -1,5 +1,6 @@
 .cache/
 .bash_history
+/nvidia-dra-controller
 /nvidia-dra-plugin
 .idea
 [._]*.sw[a-p]

cmd/nvidia-dra-controller/imex.go

@@ -0,0 +1,261 @@
+/*
+ * Copyright (c) 2024 NVIDIA CORPORATION.  All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	v1 "k8s.io/api/core/v1"
+	resourceapi "k8s.io/api/resource/v1alpha3"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/labels"
+	"k8s.io/apimachinery/pkg/selection"
+	"k8s.io/client-go/informers"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/tools/cache"
+	"k8s.io/dynamic-resource-allocation/resourceslice"
+	"k8s.io/klog/v2"
+	"k8s.io/utils/ptr"
+)
+
+const (
+	DriverName       = "gpu.nvidia.com"
+	ImexDomainLabel  = "nvidia.com/gpu.imex-domain"
+	ImexChannelLimit = 128
+)
+
+type DriverResources resourceslice.DriverResources
+
+func StartIMEXManager(ctx context.Context, config *Config) error {
+	// Build a client set config
+	csconfig, err := config.flags.kubeClientConfig.NewClientSetConfig()
+	if err != nil {
+		return fmt.Errorf("error creating client set config: %w", err)
+	}
+
+	// Create a new clientset
+	clientset, err := kubernetes.NewForConfig(csconfig)
+	if err != nil {
+		return fmt.Errorf("error creating dynamic client: %w", err)
+	}
+
+	// Fetch the current Pod object
+	pod, err := clientset.CoreV1().Pods(config.flags.namespace).Get(ctx, config.flags.podName, metav1.GetOptions{})
+	if err != nil {
+		return fmt.Errorf("error fetching pod: %w", err)
+	}
+
+	// Set the owner of the ResourceSlices we will create
+	owner := resourceslice.Owner{
+		APIVersion: "v1",
+		Kind:       "Pod",
+		Name:       pod.Name,
+		UID:        pod.UID,
+	}
+
+	// Stream added/removed IMEX domains from nodes over time
+	klog.Info("Start streaming IMEX domains from nodes...")
+	addedDomainsCh, removedDomainsCh, err := streamImexDomains(ctx, clientset)
+	if err != nil {
+		return fmt.Errorf("error streaming IMEX domains: %w", err)
+	}
+
+	// Add/Remove resource slices from IMEX domains as they come and go
+	klog.Info("Start publishing IMEX channels to ResourceSlices...")
+	err = manageResourceSlices(ctx, clientset, owner, addedDomainsCh, removedDomainsCh)
+	if err != nil {
+		return fmt.Errorf("error managing resource slices: %w", err)
+	}
+
+	return nil
+}
+
+// manageResourceSlices reacts to added and removed IMEX domains and triggers the creation / removal of resource slices accordingly.
+func manageResourceSlices(ctx context.Context, clientset kubernetes.Interface, owner resourceslice.Owner, addedDomainsCh <-chan string, removedDomainsCh <-chan string) error {
+	driverResources := resourceslice.DriverResources{}
+	controller, err := resourceslice.StartController(ctx, clientset, DriverName, owner, &driverResources)
+	if err != nil {
+		return fmt.Errorf("error starting resource slice controller: %w", err)
+	}
+
+	go func() {
+		for {
+			select {
+			case addedDomain := <-addedDomainsCh:
+				klog.Infof("Adding channels for new IMEX domain: %v", addedDomain)
+				newDriverResources := DriverResources(driverResources).DeepCopy()
+				newDriverResources.Pools[addedDomain] = generateImexChannelPool(addedDomain, ImexChannelLimit)
+				controller.Update(&newDriverResources)
+				driverResources = newDriverResources
+			case removedDomain := <-removedDomainsCh:
+				klog.Infof("Removing channels for removed IMEX domain: %v", removedDomain)
+				newDriverResources := DriverResources(driverResources).DeepCopy()
+				delete(newDriverResources.Pools, removedDomain)
+				controller.Update(&newDriverResources)
+				driverResources = newDriverResources
+			case <-ctx.Done():
+				return
+			}
+		}
+	}()
+
+	return nil
+}
+
+// DeepCopy will perform a deep copy of the provided DriverResources.
+func (d DriverResources) DeepCopy() resourceslice.DriverResources {
+	driverResources := resourceslice.DriverResources{
+		Pools: make(map[string]resourceslice.Pool),
+	}
+	for p := range d.Pools {
+		driverResources.Pools[p] = generateImexChannelPool(p, ImexChannelLimit)
+	}
+	return driverResources
+}
+
+// streamImexDomains returns two channels that streams imexDomans that are added and removed from nodes over time.
+func streamImexDomains(ctx context.Context, clientset kubernetes.Interface) (<-chan string, <-chan string, error) {
+	// Create channels to stream IMEX domain ids that are added / removed
+	addedDomainCh := make(chan string)
+	removedDomainCh := make(chan string)
+
+	// Use a map to track how many nodes are part of a given IMEX domain
+	nodesPerImexDomain := make(map[string]int)
+
+	// Build a label selector to get all nodes with ImexDomainLabel set
+	requirement, err := labels.NewRequirement(ImexDomainLabel, selection.Exists, nil)
+	if err != nil {
+		return nil, nil, fmt.Errorf("error building label selector requirement: %w", err)
+	}
+	labelSelector := labels.NewSelector().Add(*requirement).String()
+
+	// Create a shared informer factory for nodes
+	informerFactory := informers.NewSharedInformerFactoryWithOptions(
+		clientset,
+		time.Minute*10, // Resync period
+		informers.WithTweakListOptions(func(options *metav1.ListOptions) {
+			options.LabelSelector = labelSelector
+		}),
+	)
+	nodeInformer := informerFactory.Core().V1().Nodes().Informer()
+
+	// Set up event handlers for node events
+	_, err = nodeInformer.AddEventHandler(cache.ResourceEventHandlerFuncs{
+		AddFunc: func(obj interface{}) {
+			node := obj.(*v1.Node) // nolint:forcetypeassert
+			imexDomain := node.Labels[ImexDomainLabel]
+			if imexDomain != "" {
+				nodesPerImexDomain[imexDomain]++
+				if nodesPerImexDomain[imexDomain] == 1 {
+					addedDomainCh <- imexDomain
+				}
+			}
+		},
+		DeleteFunc: func(obj interface{}) {
+			node := obj.(*v1.Node) // nolint:forcetypeassert
+			imexDomain := node.Labels[ImexDomainLabel]
+			if imexDomain != "" {
+				nodesPerImexDomain[imexDomain]--
+				if nodesPerImexDomain[imexDomain] == 0 {
+					removedDomainCh <- imexDomain
+				}
+			}
+		},
+		UpdateFunc: func(oldObj, newObj interface{}) {
+			oldNode := oldObj.(*v1.Node) // nolint:forcetypeassert
+			newNode := newObj.(*v1.Node) // nolint:forcetypeassert
+
+			oldImexDomain := oldNode.Labels[ImexDomainLabel]
+			newImexDomain := newNode.Labels[ImexDomainLabel]
+
+			if oldImexDomain == newImexDomain {
+				return
+			}
+			if oldImexDomain != "" {
+				nodesPerImexDomain[oldImexDomain]--
+				if nodesPerImexDomain[oldImexDomain] == 0 {
+					removedDomainCh <- oldImexDomain
+				}
+			}
+			if newImexDomain != "" {
+				nodesPerImexDomain[newImexDomain]++
+				if nodesPerImexDomain[newImexDomain] == 1 {
+					addedDomainCh <- newImexDomain
+				}
+			}
+		},
+	})
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to create node informer: %w", err)
+	}
+
+	// Start the informer and wait for it to sync
+	go informerFactory.Start(ctx.Done())
+
+	// Wait for the informer caches to sync
+	if !cache.WaitForCacheSync(ctx.Done(), nodeInformer.HasSynced) {
+		return nil, nil, fmt.Errorf("failed to sync informer caches")
+	}
+
+	return addedDomainCh, removedDomainCh, nil
+}
+
+// generateImexChannelPool generates the contents of a ResourceSlice pool for a given IMEX domain.
+func generateImexChannelPool(imexDomain string, numChannels int) resourceslice.Pool {
+	// Generate dchannels from 0 to numChannels
+	var devices []resourceapi.Device
+	for i := 0; i < numChannels; i++ {
+		d := resourceapi.Device{
+			Name: fmt.Sprintf("imex-channel-%d", i),
+			Basic: &resourceapi.BasicDevice{
+				Attributes: map[resourceapi.QualifiedName]resourceapi.DeviceAttribute{
+					"type": {
+						StringValue: ptr.To("imex-channel"),
+					},
+					"channel": {
+						IntValue: ptr.To(int64(i)),
+					},
+				},
+			},
+		}
+		devices = append(devices, d)
+	}
+
+	// Put them in a pool named after the IMEX domain with the IMEX domain label as a node selector
+	pool := resourceslice.Pool{
+		NodeSelector: &v1.NodeSelector{
+			NodeSelectorTerms: []v1.NodeSelectorTerm{
+				{
+					MatchExpressions: []v1.NodeSelectorRequirement{
+						{
+							Key:      ImexDomainLabel,
+							Operator: v1.NodeSelectorOpIn,
+							Values: []string{
+								imexDomain,
+							},
+						},
+					},
+				},
+			},
+		},
+		Devices: devices,
+	}
+
+	return pool
+}