Adding ability to override allocatable resources via ASG tags. Fixes k…

…ubernetes#1650

cluster-autoscaler/cloudprovider/aws/aws_manager.go

@@ -247,6 +247,17 @@ func (m *AwsManager) buildNodeFromTemplate(asg *asg, template *asgTemplate) (*ap
 	node.Status.Capacity[gpu.ResourceNvidiaGPU] = *resource.NewQuantity(template.InstanceType.GPU, resource.DecimalSI)
 	node.Status.Capacity[apiv1.ResourceMemory] = *resource.NewQuantity(template.InstanceType.MemoryMb*1024*1024, resource.DecimalSI)
 
+	resourcesFromTags := extractResourceAllocatableFromAsg(template.Tags)
+	if val, ok := resourcesFromTags["cpu"]; ok {
+		node.Status.Capacity[apiv1.ResourceCPU] = val
+	}
+	if val, ok := resourcesFromTags["memory"]; ok {
+		node.Status.Capacity[apiv1.ResourceMemory] = val
+	}
+	if val, ok := resourcesFromTags["ephemeral-storage"]; ok {
+		node.Status.Capacity[apiv1.ResourceEphemeralStorage] = val
+	}
+
 	// TODO: use proper allocatable!!
 	node.Status.Allocatable = node.Status.Capacity
 
@@ -293,6 +304,28 @@ func extractLabelsFromAsg(tags []*autoscaling.TagDescription) map[string]string
 	return result
 }
 
+func extractResourceAllocatableFromAsg(tags []*autoscaling.TagDescription) map[string]resource.Quantity {
+	result := make(map[string]resource.Quantity)
+
+	for _, tag := range tags {
+		k := *tag.Key
+		v := *tag.Value
+		splits := strings.Split(k, "k8s.io/cluster-autoscaler/node-template/resources/")
+		if len(splits) > 1 {
+			label := splits[1]
+			if label != "" {
+				quantity, err := resource.ParseQuantity(v)
+				if err != nil {
+					continue
+				}
+				result[label] = quantity
+			}
+		}
+	}
+
+	return result
+}
+
 func extractTaintsFromAsg(tags []*autoscaling.TagDescription) []apiv1.Taint {
 	taints := make([]apiv1.Taint, 0)