diff --git a/tests/integration/update_cluster/cluster-autoscaler-priority-expander-custom/data/aws_s3_object_cas-priority-expander-custom.example.com-addons-bootstrap_content b/tests/integration/update_cluster/cluster-autoscaler-priority-expander-custom/data/aws_s3_object_cas-priority-expander-custom.example.com-addons-bootstrap_content
index 4f27321321c44..aef719815711d 100644
--- a/tests/integration/update_cluster/cluster-autoscaler-priority-expander-custom/data/aws_s3_object_cas-priority-expander-custom.example.com-addons-bootstrap_content
+++ b/tests/integration/update_cluster/cluster-autoscaler-priority-expander-custom/data/aws_s3_object_cas-priority-expander-custom.example.com-addons-bootstrap_content
@@ -41,7 +41,7 @@ spec:
     version: 9.99.0
   - id: k8s-1.15
     manifest: cluster-autoscaler.addons.k8s.io/k8s-1.15.yaml
-    manifestHash: 41dc4453160d8f9ae80a1b9beb288252649912296ca56dc3f70dda6cf3cbfaa1
+    manifestHash: 8170c20f6d8184dff873231d153b5f6d93f5d8dd75f739963f6d091b6b7f2187
     name: cluster-autoscaler.addons.k8s.io
     selector:
       k8s-addon: cluster-autoscaler.addons.k8s.io
diff --git a/tests/integration/update_cluster/cluster-autoscaler-priority-expander-custom/data/aws_s3_object_cas-priority-expander-custom.example.com-addons-cluster-autoscaler.addons.k8s.io-k8s-1.15_content b/tests/integration/update_cluster/cluster-autoscaler-priority-expander-custom/data/aws_s3_object_cas-priority-expander-custom.example.com-addons-cluster-autoscaler.addons.k8s.io-k8s-1.15_content
index a73b8772b41b0..d39f6f7e5574b 100644
--- a/tests/integration/update_cluster/cluster-autoscaler-priority-expander-custom/data/aws_s3_object_cas-priority-expander-custom.example.com-addons-cluster-autoscaler.addons.k8s.io-k8s-1.15_content
+++ b/tests/integration/update_cluster/cluster-autoscaler-priority-expander-custom/data/aws_s3_object_cas-priority-expander-custom.example.com-addons-cluster-autoscaler.addons.k8s.io-k8s-1.15_content
@@ -282,12 +282,12 @@ spec:
 apiVersion: v1
 data:
   priorities: |-
-    "0":
+    0:
     - .*
-    "50":
-    - .*low.*
-    "100":
+    100:
     - .*high.*
+    50:
+    - .*low.*
 kind: ConfigMap
 metadata:
   creationTimestamp: null
diff --git a/tests/integration/update_cluster/cluster-autoscaler-priority-expander/data/aws_s3_object_cas-priority-expander.example.com-addons-bootstrap_content b/tests/integration/update_cluster/cluster-autoscaler-priority-expander/data/aws_s3_object_cas-priority-expander.example.com-addons-bootstrap_content
index a01634b2c5395..5bdf4d1741b87 100644
--- a/tests/integration/update_cluster/cluster-autoscaler-priority-expander/data/aws_s3_object_cas-priority-expander.example.com-addons-bootstrap_content
+++ b/tests/integration/update_cluster/cluster-autoscaler-priority-expander/data/aws_s3_object_cas-priority-expander.example.com-addons-bootstrap_content
@@ -41,7 +41,7 @@ spec:
     version: 9.99.0
   - id: k8s-1.15
     manifest: cluster-autoscaler.addons.k8s.io/k8s-1.15.yaml
-    manifestHash: 9b04006b3916dbc0e5fe22f2a23a1fa72d1665e12fe1b96f4cd7707cb823f7d7
+    manifestHash: f63778b4b540b89fff019defd1eec7e2320233b6eb54b46897a00589f3fceb92
     name: cluster-autoscaler.addons.k8s.io
     selector:
       k8s-addon: cluster-autoscaler.addons.k8s.io
diff --git a/tests/integration/update_cluster/cluster-autoscaler-priority-expander/data/aws_s3_object_cas-priority-expander.example.com-addons-cluster-autoscaler.addons.k8s.io-k8s-1.15_content b/tests/integration/update_cluster/cluster-autoscaler-priority-expander/data/aws_s3_object_cas-priority-expander.example.com-addons-cluster-autoscaler.addons.k8s.io-k8s-1.15_content
index c6ec180358497..1f33703b56fc3 100644
--- a/tests/integration/update_cluster/cluster-autoscaler-priority-expander/data/aws_s3_object_cas-priority-expander.example.com-addons-cluster-autoscaler.addons.k8s.io-k8s-1.15_content
+++ b/tests/integration/update_cluster/cluster-autoscaler-priority-expander/data/aws_s3_object_cas-priority-expander.example.com-addons-cluster-autoscaler.addons.k8s.io-k8s-1.15_content
@@ -282,12 +282,12 @@ spec:
 apiVersion: v1
 data:
   priorities: |-
-    "0":
+    0:
     - nodes.cas-priority-expander.example.com
-    "50":
-    - nodes-low-priority.cas-priority-expander.example.com
-    "100":
+    100:
     - nodes-high-priority.cas-priority-expander.example.com
+    50:
+    - nodes-low-priority.cas-priority-expander.example.com
 kind: ConfigMap
 metadata:
   creationTimestamp: null
diff --git a/upup/models/cloudup/resources/addons/cluster-autoscaler.addons.k8s.io/k8s-1.15.yaml.template b/upup/models/cloudup/resources/addons/cluster-autoscaler.addons.k8s.io/k8s-1.15.yaml.template
index d10afe403a111..95799ca5d243b 100644
--- a/upup/models/cloudup/resources/addons/cluster-autoscaler.addons.k8s.io/k8s-1.15.yaml.template
+++ b/upup/models/cloudup/resources/addons/cluster-autoscaler.addons.k8s.io/k8s-1.15.yaml.template
@@ -270,8 +270,7 @@ metadata:
     k8s-addon: cluster-autoscaler.addons.k8s.io
     k8s-app: cluster-autoscaler
 data:
-  priorities: |-
-    {{- ClusterAutoscalerPriorities | ToYAML | nindent 4 }}
+  priorities: |- {{ ClusterAutoscalerPriorities | nindent 4 }}
 {{ end }}
 ---
 # Source: cluster-autoscaler/templates/deployment.yaml
diff --git a/upup/pkg/fi/cloudup/template_functions.go b/upup/pkg/fi/cloudup/template_functions.go
index 8a0c147a5f9c6..79c7d1244132b 100644
--- a/upup/pkg/fi/cloudup/template_functions.go
+++ b/upup/pkg/fi/cloudup/template_functions.go
@@ -70,6 +70,7 @@ import (
 	"k8s.io/kops/upup/pkg/fi/cloudup/openstack"
 	"k8s.io/kops/upup/pkg/fi/cloudup/scaleway"
 	"k8s.io/kops/util/pkg/env"
+	"k8s.io/kops/util/pkg/maps"
 	"sigs.k8s.io/yaml"
 )
 
@@ -337,19 +338,26 @@ func (tf *TemplateFunctions) AddTo(dest template.FuncMap, secretStore fi.SecretS
 	dest["UseServiceAccountExternalPermissions"] = tf.UseServiceAccountExternalPermissions
 
 	if cluster.Spec.ClusterAutoscaler != nil {
-		dest["ClusterAutoscalerPriorities"] = func() map[string][]string {
+		dest["ClusterAutoscalerPriorities"] = func() string {
 			priorities := make(map[string][]string)
 			if cluster.Spec.ClusterAutoscaler.CustomPriorityExpanderConfig != nil {
 				priorities = cluster.Spec.ClusterAutoscaler.CustomPriorityExpanderConfig
 			} else {
 				for name, spec := range tf.GetNodeInstanceGroups() {
-
 					if spec.Autoscale != nil {
-						priorities[fmt.Sprint(spec.AutoscalePriority)] = append(priorities[fmt.Sprint(spec.AutoscalePriority)], fmt.Sprintf("%s.%s", name, tf.ClusterName()))
+						priorities[strconv.Itoa(int(spec.AutoscalePriority))] = append(priorities[strconv.Itoa(int(spec.AutoscalePriority))], fmt.Sprintf("%s.%s", name, tf.ClusterName()))
 					}
 				}
 			}
-			return priorities
+
+			var prioritiesStr []string
+			for _, prio := range maps.SortedKeys(priorities) {
+				prioritiesStr = append(prioritiesStr, fmt.Sprintf("%s:", prio))
+				for _, value := range priorities[prio] {
+					prioritiesStr = append(prioritiesStr, fmt.Sprintf("- %s", value))
+				}
+			}
+			return strings.Join(prioritiesStr, "\n")
 		}
 		dest["CreateClusterAutoscalerPriorityConfig"] = func() bool {
 			return fi.ValueOf(cluster.Spec.ClusterAutoscaler.CreatePriorityExpenderConfig)