92 lines
3.6 KiB
Go
92 lines
3.6 KiB
Go
/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package priorities
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import (
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"fmt"
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"k8s.io/api/core/v1"
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schedulerapi "k8s.io/kubernetes/plugin/pkg/scheduler/api"
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"k8s.io/kubernetes/plugin/pkg/scheduler/schedulercache"
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"github.com/golang/glog"
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)
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// LeastRequestedPriority is a priority function that favors nodes with fewer requested resources.
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// It calculates the percentage of memory and CPU requested by pods scheduled on the node, and prioritizes
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// based on the minimum of the average of the fraction of requested to capacity.
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// Details: cpu((capacity - sum(requested)) * 10 / capacity) + memory((capacity - sum(requested)) * 10 / capacity) / 2
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func LeastRequestedPriorityMap(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (schedulerapi.HostPriority, error) {
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var nonZeroRequest *schedulercache.Resource
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if priorityMeta, ok := meta.(*priorityMetadata); ok {
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nonZeroRequest = priorityMeta.nonZeroRequest
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} else {
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// We couldn't parse metadata - fallback to computing it.
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nonZeroRequest = getNonZeroRequests(pod)
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}
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return calculateUnusedPriority(pod, nonZeroRequest, nodeInfo)
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}
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// The unused capacity is calculated on a scale of 0-10
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// 0 being the lowest priority and 10 being the highest.
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// The more unused resources the higher the score is.
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func calculateUnusedScore(requested int64, capacity int64, node string) int64 {
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if capacity == 0 {
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return 0
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}
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if requested > capacity {
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glog.V(10).Infof("Combined requested resources %d from existing pods exceeds capacity %d on node %s",
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requested, capacity, node)
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return 0
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}
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return ((capacity - requested) * 10) / capacity
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}
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// Calculates host priority based on the amount of unused resources.
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// 'node' has information about the resources on the node.
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// 'pods' is a list of pods currently scheduled on the node.
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func calculateUnusedPriority(pod *v1.Pod, podRequests *schedulercache.Resource, nodeInfo *schedulercache.NodeInfo) (schedulerapi.HostPriority, error) {
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node := nodeInfo.Node()
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if node == nil {
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return schedulerapi.HostPriority{}, fmt.Errorf("node not found")
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}
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allocatableResources := nodeInfo.AllocatableResource()
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totalResources := *podRequests
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totalResources.MilliCPU += nodeInfo.NonZeroRequest().MilliCPU
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totalResources.Memory += nodeInfo.NonZeroRequest().Memory
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cpuScore := calculateUnusedScore(totalResources.MilliCPU, allocatableResources.MilliCPU, node.Name)
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memoryScore := calculateUnusedScore(totalResources.Memory, allocatableResources.Memory, node.Name)
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if glog.V(10) {
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// We explicitly don't do glog.V(10).Infof() to avoid computing all the parameters if this is
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// not logged. There is visible performance gain from it.
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glog.V(10).Infof(
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"%v -> %v: Least Requested Priority, capacity %d millicores %d memory bytes, total request %d millicores %d memory bytes, score %d CPU %d memory",
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pod.Name, node.Name,
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allocatableResources.MilliCPU, allocatableResources.Memory,
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totalResources.MilliCPU, totalResources.Memory,
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cpuScore, memoryScore,
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)
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}
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return schedulerapi.HostPriority{
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Host: node.Name,
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Score: int((cpuScore + memoryScore) / 2),
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}, nil
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}
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