Fixes a bug with affinity, where OR semantic was treated as AND

pkg/controllers/allocation/scheduling/preferences.go

@@ -83,8 +83,8 @@ func (p *Preferences) removePreferredNodeAffinityTerm(ctx context.Context, pod *
 	terms := pod.Spec.Affinity.NodeAffinity.PreferredDuringSchedulingIgnoredDuringExecution
 	// Remove the terms if there are any (terms are an OR semantic)
 	if len(terms) > 0 {
-		// Sort ascending by weight to remove lightest preferences first
-		sort.SliceStable(terms, func(i, j int) bool { return terms[i].Weight < terms[j].Weight })
+		// Sort descending by weight to remove heaviest preferences to try lighter ones
+		sort.SliceStable(terms, func(i, j int) bool { return terms[i].Weight > terms[j].Weight })
 		pod.Spec.Affinity.NodeAffinity.PreferredDuringSchedulingIgnoredDuringExecution = terms[1:]
 		return ptr.String(fmt.Sprintf("spec.affinity.nodeAffinity.preferredDuringSchedulingIgnoredDuringExecution[0]=%s", pretty.Concise(terms[0])))
 	}

pkg/scheduling/nodeaffinity.go

@@ -15,6 +15,8 @@ limitations under the License.
 package scheduling
 
 import (
+	"sort"
+
 	"github.com/awslabs/karpenter/pkg/utils/functional"
 	v1 "k8s.io/api/core/v1"
 )
@@ -31,14 +33,15 @@ func NodeAffinityFor(pods ...*v1.Pod) (nodeAffinity NodeAffinity) {
 		if pod.Spec.Affinity == nil || pod.Spec.Affinity.NodeAffinity == nil {
 			continue
 		}
-		// Preferences are treated as requirements. An outer loop will iteratively unconstrain them if unsatisfiable
-		for _, term := range pod.Spec.Affinity.NodeAffinity.PreferredDuringSchedulingIgnoredDuringExecution {
-			nodeAffinity = append(nodeAffinity, term.Preference.MatchExpressions...)
+		// Select heaviest preference and treat as a requirement. An outer loop will iteratively unconstrain them if unsatisfiable.
+		if preferred := pod.Spec.Affinity.NodeAffinity.PreferredDuringSchedulingIgnoredDuringExecution; len(preferred) > 0 {
+			sort.Slice(preferred, (func(i int, j int) bool { return preferred[i].Weight > preferred[j].Weight }))
+			nodeAffinity = append(nodeAffinity, preferred[0].Preference.MatchExpressions...)
 		}
-		if pod.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution != nil {
-			for _, term := range pod.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution.NodeSelectorTerms {
-				nodeAffinity = append(nodeAffinity, term.MatchExpressions...)
-			}
+		// Select first requirement. An outer loop will iteratively remove OR requirements if unsatisfiable
+		if pod.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution != nil &&
+			len(pod.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution.NodeSelectorTerms) > 0 {
+			nodeAffinity = append(nodeAffinity, pod.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution.NodeSelectorTerms[0].MatchExpressions...)
 		}
 	}
 	return nodeAffinity

website/content/en/docs/getting-started/_index.md

@@ -177,7 +177,8 @@ metadata:
 spec:
   provider:
     instanceProfile: KarpenterNodeInstanceProfile-${CLUSTER_NAME}
-    capacityType: spot
+    capacityTypes:
+      - spot
     cluster:
       name: ${CLUSTER_NAME}
       endpoint: $(aws eks describe-cluster --name ${CLUSTER_NAME} --query "cluster.endpoint" --output json)