Cluster autoscaler friendly scheduling algorithm

plugin/pkg/scheduler/algorithmprovider/defaults/defaults.go

@@ -34,7 +34,8 @@ import (
 
 const (
 	// GCE instances can have up to 16 PD volumes attached.
-	DefaultMaxGCEPDVolumes = 16
+	DefaultMaxGCEPDVolumes    = 16
+	ClusterAutoscalerProvider = "ClusterAutoscalerProvider"
 )
 
 // getMaxVols checks the max PD volumes environment variable, otherwise returning a default value
@@ -54,6 +55,9 @@ func getMaxVols(defaultVal int) int {
 
 func init() {
 	factory.RegisterAlgorithmProvider(factory.DefaultProvider, defaultPredicates(), defaultPriorities())
+	// Cluster autoscaler friendly scheduling algorithm.
+	factory.RegisterAlgorithmProvider(ClusterAutoscalerProvider, defaultPredicates(),
+		replace(defaultPriorities(), "LeastRequestedPriority", "MostRequestedPriority"))
 	// EqualPriority is a prioritizer function that gives an equal weight of one to all nodes
 	// Register the priority function so that its available
 	// but do not include it as part of the default priorities
@@ -97,6 +101,15 @@ func init() {
 	factory.RegisterPriorityFunction("MostRequestedPriority", priorities.MostRequestedPriority, 1)
 }
 
+func replace(set sets.String, replaceWhat, replaceWith string) sets.String {
+	result := sets.NewString(set.List()...)
+	if result.Has(replaceWhat) {
+		result.Delete(replaceWhat)
+		result.Insert(replaceWith)
+	}
+	return result
+}
+
 func defaultPredicates() sets.String {
 	return sets.NewString(
 		// Fit is determined by non-conflicting disk volumes.