scorer.go

Documentation: k8s.io/kubernetes/pkg/scheduler/framework/plugins/volumebinding

     1  /*
     2  Copyright 2021 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package volumebinding
    18  
    19  import (
    20  	"math"
    21  
    22  	"k8s.io/kubernetes/pkg/scheduler/framework/plugins/helper"
    23  )
    24  
    25  // classResourceMap holds a map of storage class to resource.
    26  type classResourceMap map[string]*StorageResource
    27  
    28  // volumeCapacityScorer calculates the score based on class storage resource information.
    29  type volumeCapacityScorer func(classResourceMap) int64
    30  
    31  // buildScorerFunction builds volumeCapacityScorer from the scoring function shape.
    32  func buildScorerFunction(scoringFunctionShape helper.FunctionShape) volumeCapacityScorer {
    33  	rawScoringFunction := helper.BuildBrokenLinearFunction(scoringFunctionShape)
    34  	f := func(requested, capacity int64) int64 {
    35  		if capacity == 0 || requested > capacity {
    36  			return rawScoringFunction(maxUtilization)
    37  		}
    38  
    39  		return rawScoringFunction(requested * maxUtilization / capacity)
    40  	}
    41  	return func(classResources classResourceMap) int64 {
    42  		var nodeScore int64
    43  		// in alpha stage, all classes have the same weight
    44  		weightSum := len(classResources)
    45  		if weightSum == 0 {
    46  			return 0
    47  		}
    48  		for _, resource := range classResources {
    49  			classScore := f(resource.Requested, resource.Capacity)
    50  			nodeScore += classScore
    51  		}
    52  		return int64(math.Round(float64(nodeScore) / float64(weightSum)))
    53  	}
    54  }
    55
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