Node affinity to odiglet nodes

cli/cmd/resources/odiglet.go

@@ -96,6 +96,7 @@ func NewOdigletClusterRole(psp bool) *rbacv1.ClusterRole {
 					"get",
 					"list",
 					"watch",
+					"patch",
 				},
 				APIGroups: []string{""},
 				Resources: []string{

common/consts/consts.go

@@ -26,6 +26,9 @@ const (
 	// Used to label instrumentation instances by the corresponding
 	// instrumented app for better query performance.
 	InstrumentedAppNameLabel = "instrumented-app"
+	// Used to indicate that the odiglet is installed on a node.
+	OdigletInstalledLabel      = "odiglet-installed"
+	OdigletInstalledLabelValue = "true"
 )
 
 var (

helm/odigos/templates/odiglet/clusterrole.yaml

@@ -8,13 +8,21 @@ rules:
     resources:
       - configmaps
       - namespaces
-      - nodes
       - pods
       - services
     verbs:
       - get
       - list
       - watch
+  - apiGroups:
+      - ""
+    resources:
+      - nodes
+    verbs:
+      - get
+      - list
+      - watch
+      - patch      
   - apiGroups:
       - ""
     resources:

instrumentor/controllers/instrumentationdevice/common.go

@@ -13,6 +13,7 @@ import (
 	"github.com/odigos-io/odigos/k8sutils/pkg/conditions"
 	odigosk8sconsts "github.com/odigos-io/odigos/k8sutils/pkg/consts"
 	"github.com/odigos-io/odigos/k8sutils/pkg/env"
+	"github.com/odigos-io/odigos/k8sutils/pkg/pod"
 	"github.com/odigos-io/odigos/k8sutils/pkg/workload"
 	appsv1 "k8s.io/api/apps/v1"
 	corev1 "k8s.io/api/core/v1"
@@ -128,6 +129,9 @@ func addInstrumentationDeviceToWorkload(ctx context.Context, kubeClient client.C
 		}
 
 		err, deviceApplied, tempDevicePartiallyApplied := instrumentation.ApplyInstrumentationDevicesToPodTemplate(podSpec, runtimeDetails, otelSdkToUse, obj, logger)
+
+		pod.AddOdigletInstalledAffinity(podSpec, consts.OdigletInstalledLabel, consts.OdigletInstalledLabelValue)
+
 		if err != nil {
 			return err
 		}
@@ -179,6 +183,8 @@ func removeInstrumentationDeviceFromWorkload(ctx context.Context, kubeClient cli
 		// If instrumentation device is removed successfully, remove odigos.io/inject-instrumentation label to disable the webhook
 		instrumentation.RemoveInjectInstrumentationLabel(podSpec)
 
+		pod.RemoveOdigletInstalledAffinity(podSpec, consts.OdigletInstalledLabel, consts.OdigletInstalledLabelValue)
+
 		instrumentation.RevertInstrumentationDevices(podSpec)
 
 		err = instrumentation.RevertEnvOverwrites(workloadObj, podSpec)

k8sutils/pkg/node/node.go

@@ -0,0 +1,27 @@
+package node
+
+import (
+	"context"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/client-go/kubernetes"
+)
+
+func AddLabelToNode(ctx context.Context, clientset *kubernetes.Clientset, nodeName string, labelKey string, labelValue string) error {
+	patch := []byte(`{"metadata": {"labels": {"` + labelKey + `": "` + labelValue + `"}}}`)
+	_, err := clientset.CoreV1().Nodes().Patch(ctx, nodeName, types.StrategicMergePatchType, patch, metav1.PatchOptions{})
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func RemoveLabelFromNode(ctx context.Context, clientset *kubernetes.Clientset, nodeName string, labelKey string) error {
+	patch := []byte(`{"metadata": {"labels": {"` + labelKey + `": null}}}`)
+	_, err := clientset.CoreV1().Nodes().Patch(ctx, nodeName, types.StrategicMergePatchType, patch, metav1.PatchOptions{})
+	if err != nil {
+		return err
+	}
+	return nil
+}

k8sutils/pkg/pod/pod.go

@@ -0,0 +1,112 @@
+package pod
+
+import (
+	corev1 "k8s.io/api/core/v1"
+)
+
+func AddOdigletInstalledAffinity(original *corev1.PodTemplateSpec, nodeLabelKey, nodeLabelValue string) {
+	// Ensure Affinity exists
+	if original.Spec.Affinity == nil {
+		original.Spec.Affinity = &corev1.Affinity{}
+	}
+
+	// Ensure NodeAffinity exists
+	if original.Spec.Affinity.NodeAffinity == nil {
+		original.Spec.Affinity.NodeAffinity = &corev1.NodeAffinity{}
+	}
+
+	// Ensure RequiredDuringSchedulingIgnoredDuringExecution exists
+	if original.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution == nil {
+		original.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution = &corev1.NodeSelector{
+			NodeSelectorTerms: []corev1.NodeSelectorTerm{},
+		}
+	}
+
+	// Check if the term already exists
+	for _, term := range original.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution.NodeSelectorTerms {
+		for _, expr := range term.MatchExpressions {
+			if expr.Key == nodeLabelKey && expr.Operator == corev1.NodeSelectorOpIn {
+				for _, val := range expr.Values {
+					if val == nodeLabelValue {
+						// The term already exists, so return without adding a duplicate
+						return
+					}
+				}
+			}
+		}
+	}
+
+	// Append the new NodeSelectorTerm if it doesn't exist
+	newTerm := corev1.NodeSelectorTerm{
+		MatchExpressions: []corev1.NodeSelectorRequirement{
+			{
+				Key:      nodeLabelKey,
+				Operator: corev1.NodeSelectorOpIn,
+				Values:   []string{nodeLabelValue},
+			},
+		},
+	}
+	original.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution.NodeSelectorTerms = append(
+		original.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution.NodeSelectorTerms,
+		newTerm,
+	)
+}
+
+// RemoveNodeAffinityFromPodTemplate removes a specific NodeAffinity rule from a PodTemplateSpec if it exists.
+func RemoveOdigletInstalledAffinity(original *corev1.PodTemplateSpec, nodeLabelKey, nodeLabelValue string) {
+	if original.Spec.Affinity == nil || original.Spec.Affinity.NodeAffinity == nil {
+		// No affinity or node affinity present, nothing to remove
+		return
+	}
+
+	if original.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution == nil {
+		// No required node affinity present, nothing to remove
+		return
+	}
+
+	// Iterate over NodeSelectorTerms and remove terms that match the key and value
+	filteredTerms := []corev1.NodeSelectorTerm{}
+	for _, term := range original.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution.NodeSelectorTerms {
+		filteredExpressions := []corev1.NodeSelectorRequirement{}
+		for _, expr := range term.MatchExpressions {
+			// Only keep expressions that don't match the given key and value
+			if !(expr.Key == nodeLabelKey && expr.Operator == corev1.NodeSelectorOpIn && containsValue(expr.Values, nodeLabelValue)) {
+				filteredExpressions = append(filteredExpressions, expr)
+			}
+		}
+
+		// Only add the term if it still has expressions after filtering
+		if len(filteredExpressions) > 0 {
+			term.MatchExpressions = filteredExpressions
+			filteredTerms = append(filteredTerms, term)
+		}
+	}
+
+	// Update the NodeSelectorTerms with the filtered list or set to nil if empty
+	if len(filteredTerms) > 0 {
+		original.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution.NodeSelectorTerms = filteredTerms
+	} else {
+		original.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution = nil
+	}
+
+	// Clean up empty NodeAffinity if needed
+	if original.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution == nil &&
+		original.Spec.Affinity.NodeAffinity.PreferredDuringSchedulingIgnoredDuringExecution == nil {
+		original.Spec.Affinity.NodeAffinity = nil
+	}
+
+	// Clean up empty Affinity if needed
+	if original.Spec.Affinity.NodeAffinity == nil && original.Spec.Affinity.PodAffinity == nil && original.Spec.Affinity.PodAntiAffinity == nil {
+		original.Spec.Affinity = nil
+	}
+}
+
+// Helper function to check if a value is in a slice
+func containsValue(values []string, value string) bool {
+	for _, v := range values {
+		if v == value {
+			return true
+		}
+	}
+	return false
+}

odiglet/cmd/main.go

@@ -4,13 +4,15 @@ import (
 	"context"
 	"os"
 
+	consts "github.com/odigos-io/odigos/common/consts"
+	detector "github.com/odigos-io/odigos/odiglet/pkg/detector"
 	"github.com/odigos-io/odigos/odiglet/pkg/ebpf/sdks"
 	"github.com/odigos-io/odigos/odiglet/pkg/instrumentation/fs"
-	detector "github.com/odigos-io/odigos/odiglet/pkg/detector"
 
 	"github.com/kubevirt/device-plugin-manager/pkg/dpm"
 	"github.com/odigos-io/odigos/common"
 	k8senv "github.com/odigos-io/odigos/k8sutils/pkg/env"
+	k8snode "github.com/odigos-io/odigos/k8sutils/pkg/node"
 	"github.com/odigos-io/odigos/odiglet/pkg/ebpf"
 	"github.com/odigos-io/odigos/odiglet/pkg/env"
 	"github.com/odigos-io/odigos/odiglet/pkg/instrumentation"
@@ -109,6 +111,12 @@ func main() {
 		os.Exit(-1)
 	}
 
+	// add label of Odiglet Installed so the k8s-scheduler can schedule instrumented pods on this nodes
+	if err := k8snode.AddLabelToNode(ctx, clientset, env.Current.NodeName, consts.OdigletInstalledLabel, "true"); err != nil {
+		log.Logger.Error(err, "Failed to add label to the node")
+		os.Exit(-1)
+	}
+
 	<-ctx.Done()
 	for _, director := range ebpfDirectors {
 		director.Shutdown()
@@ -118,6 +126,10 @@ func main() {
 		log.Logger.Error(err, "Failed to stop runtime detector")
 		os.Exit(-1)
 	}
+	// Remove the label before exiting
+	if err := k8snode.RemoveLabelFromNode(ctx, clientset, env.Current.NodeName, consts.OdigletInstalledLabel); err != nil {
+		log.Logger.Error(err, "Failed to remove label from the node")
+	}
 	log.Logger.V(0).Info("odiglet exiting")
 }