diff --git a/tests/fixture/tmpnet/flags/kube_runtime.go b/tests/fixture/tmpnet/flags/kube_runtime.go
index cc5304cb7952..3eee81ea99d9 100644
--- a/tests/fixture/tmpnet/flags/kube_runtime.go
+++ b/tests/fixture/tmpnet/flags/kube_runtime.go
@@ -20,10 +20,9 @@ const (
 )
 
 var (
-	errKubeNamespaceRequired       = errors.New("--kube-namespace is required")
-	errKubeImageRequired           = errors.New("--kube-image is required")
-	errKubeMinVolumeSizeRequired   = fmt.Errorf("--kube-volume-size must be >= %d", tmpnet.MinimumVolumeSizeGB)
-	errKubeSchedulingLabelRequired = errors.New("--kube-scheduling-label-key and --kube-scheduling-label-value are required when --kube-use-exclusive-scheduling is enabled")
+	errKubeNamespaceRequired     = errors.New("--kube-namespace is required")
+	errKubeImageRequired         = errors.New("--kube-image is required")
+	errKubeMinVolumeSizeRequired = fmt.Errorf("--kube-volume-size must be >= %d", tmpnet.MinimumVolumeSizeGB)
 )
 
 type kubeRuntimeVars struct {
@@ -77,13 +76,13 @@ func (v *kubeRuntimeVars) register(stringVar varFunc[string], uintVar varFunc[ui
 	stringVar(
 		&v.schedulingLabelKey,
 		"kube-scheduling-label-key",
-		"purpose",
+		"",
 		kubeDocPrefix+"The label key to use for exclusive scheduling for node selection and toleration",
 	)
 	stringVar(
 		&v.schedulingLabelValue,
 		"kube-scheduling-label-value",
-		"higher-spec",
+		"",
 		kubeDocPrefix+"The label value to use for exclusive scheduling for node selection and toleration",
 	)
 }
@@ -98,9 +97,6 @@ func (v *kubeRuntimeVars) getKubeRuntimeConfig() (*tmpnet.KubeRuntimeConfig, err
 	if v.volumeSizeGB < tmpnet.MinimumVolumeSizeGB {
 		return nil, errKubeMinVolumeSizeRequired
 	}
-	if v.useExclusiveScheduling && (len(v.schedulingLabelKey) == 0 || len(v.schedulingLabelValue) == 0) {
-		return nil, errKubeSchedulingLabelRequired
-	}
 	return &tmpnet.KubeRuntimeConfig{
 		ConfigPath:             v.config.Path,
 		ConfigContext:          v.config.Context,
diff --git a/tests/fixture/tmpnet/kube_runtime.go b/tests/fixture/tmpnet/kube_runtime.go
index c3bb4e72e4ab..4f5343ab84ed 100644
--- a/tests/fixture/tmpnet/kube_runtime.go
+++ b/tests/fixture/tmpnet/kube_runtime.go
@@ -21,6 +21,7 @@ import (
 
 	"github.com/ava-labs/avalanchego/config"
 	"github.com/ava-labs/avalanchego/ids"
+	"github.com/ava-labs/avalanchego/utils/logging"
 
 	corev1 "k8s.io/api/core/v1"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
@@ -49,8 +50,13 @@ const (
 	// are never scheduled to the same nodes.
 	antiAffinityLabelKey   = "tmpnet-scheduling"
 	antiAffinityLabelValue = "exclusive"
+
+	// Name of config map containing tmpnet defaults
+	defaultsConfigMapName = "tmpnet-defaults"
 )
 
+var errMissingSchedulingLabels = errors.New("--kube-scheduling-label-key and --kube-scheduling-label-value are required when exclusive scheduling is enabled")
+
 type KubeRuntimeConfig struct {
 	// Path to the kubeconfig file identifying the target cluster
 	ConfigPath string `json:"configPath,omitempty"`
@@ -72,6 +78,53 @@ type KubeRuntimeConfig struct {
 	SchedulingLabelValue string `json:"schedulingLabelValue,omitempty"`
 }
 
+// ensureDefaults sets cluster-specific defaults for fields not already set by flags.
+func (c *KubeRuntimeConfig) ensureDefaults(ctx context.Context, log logging.Logger) error {
+	requireSchedulingDefaults := c.UseExclusiveScheduling && (len(c.SchedulingLabelKey) == 0 || len(c.SchedulingLabelValue) == 0)
+	if !requireSchedulingDefaults {
+		return nil
+	}
+
+	clientset, err := GetClientset(log, c.ConfigPath, c.ConfigContext)
+	if err != nil {
+		return err
+	}
+
+	log.Info("attempting to retrieve configmap containing tmpnet defaults",
+		zap.String("namespace", c.Namespace),
+		zap.String("configMap", defaultsConfigMapName),
+	)
+
+	configMap, err := clientset.CoreV1().ConfigMaps(c.Namespace).Get(ctx, defaultsConfigMapName, metav1.GetOptions{})
+	if err != nil {
+		return fmt.Errorf("failed to get ConfigMap: %w", err)
+	}
+
+	var (
+		schedulingLabelKey   = configMap.Data["schedulingLabelKey"]
+		schedulingLabelValue = configMap.Data["schedulingLabelValue"]
+	)
+	if len(c.SchedulingLabelKey) == 0 && len(schedulingLabelKey) > 0 {
+		log.Info("setting default value for SchedulingLabelKey",
+			zap.String("schedulingLabelKey", schedulingLabelKey),
+		)
+		c.SchedulingLabelKey = schedulingLabelKey
+	}
+	if len(c.SchedulingLabelValue) == 0 && len(schedulingLabelValue) > 0 {
+		log.Info("setting default value for SchedulingLabelValue",
+			zap.String("schedulingLabelValue", schedulingLabelValue),
+		)
+		c.SchedulingLabelValue = schedulingLabelValue
+	}
+
+	// Validate that the scheduling labels are now set
+	if len(c.SchedulingLabelKey) == 0 || len(c.SchedulingLabelValue) == 0 {
+		return errMissingSchedulingLabels
+	}
+
+	return nil
+}
+
 type KubeRuntime struct {
 	node *Node
 }
diff --git a/tests/fixture/tmpnet/network.go b/tests/fixture/tmpnet/network.go
index fd54079049f4..b990ed114393 100644
--- a/tests/fixture/tmpnet/network.go
+++ b/tests/fixture/tmpnet/network.go
@@ -177,7 +177,7 @@ func BootstrapNewNetwork(
 	if err := checkVMBinaries(log, network.Subnets, network.DefaultRuntimeConfig.Process); err != nil {
 		return err
 	}
-	if err := network.EnsureDefaultConfig(log); err != nil {
+	if err := network.EnsureDefaultConfig(ctx, log); err != nil {
 		return err
 	}
 	if err := network.Create(rootNetworkDir); err != nil {
@@ -234,7 +234,14 @@ func ReadNetwork(ctx context.Context, log logging.Logger, dir string) (*Network,
 }
 
 // Initializes a new network with default configuration.
-func (n *Network) EnsureDefaultConfig(log logging.Logger) error {
+func (n *Network) EnsureDefaultConfig(ctx context.Context, log logging.Logger) error {
+	// Populate runtime defaults before logging it
+	if n.DefaultRuntimeConfig.Kube != nil {
+		if err := n.DefaultRuntimeConfig.Kube.ensureDefaults(ctx, log); err != nil {
+			return err
+		}
+	}
+
 	log.Info("preparing configuration for new network",
 		zap.Any("runtimeConfig", n.DefaultRuntimeConfig),
 	)
diff --git a/tests/fixture/tmpnet/network_test.go b/tests/fixture/tmpnet/network_test.go
index fa789d7e9935..c632b41186b0 100644
--- a/tests/fixture/tmpnet/network_test.go
+++ b/tests/fixture/tmpnet/network_test.go
@@ -26,7 +26,7 @@ func TestNetworkSerialization(t *testing.T) {
 	network.PrimarySubnetConfig = ConfigMap{
 		"validatorOnly": true,
 	}
-	require.NoError(network.EnsureDefaultConfig(logging.NoLog{}))
+	require.NoError(network.EnsureDefaultConfig(ctx, logging.NoLog{}))
 	require.NoError(network.Create(tmpDir))
 	// Ensure node runtime is initialized
 	require.NoError(network.readNodes(ctx))