ec83143342
Previously, separate interfaces were defined for Reserve and Unreserve plugins. However, in nearly all cases, a plugin that allocates a resource using Reserve will likely want to register itself for Unreserve as well in order to free the allocated resource at the end of a failed scheduling/binding cycle. Having separate plugins for Reserve and Unreserve also adds unnecessary config toil. To that end, this patch aims to merge the two plugins into a single interface called a ReservePlugin that requires implementing both the Reserve and Unreserve methods.
93 lines
3.3 KiB
Go
93 lines
3.3 KiB
Go
/*
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Copyright 2019 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 stateful
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import (
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"context"
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"fmt"
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"sync"
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v1 "k8s.io/api/core/v1"
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"k8s.io/apimachinery/pkg/runtime"
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"k8s.io/klog/v2"
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framework "k8s.io/kubernetes/pkg/scheduler/framework/v1alpha1"
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)
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// MultipointExample is an example plugin that is executed at multiple extension points.
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// This plugin is stateful. It receives arguments at initialization (NewMultipointPlugin)
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// and changes its state when it is executed.
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type MultipointExample struct {
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executionPoints []string
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mu sync.RWMutex
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}
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var _ framework.ReservePlugin = &MultipointExample{}
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var _ framework.PreBindPlugin = &MultipointExample{}
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// Name is the name of the plug used in Registry and configurations.
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const Name = "multipoint-plugin-example"
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// Name returns name of the plugin. It is used in logs, etc.
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func (mp *MultipointExample) Name() string {
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return Name
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}
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// Reserve is the function invoked by the framework at "reserve" extension
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// point. In this trivial example, the Reserve method allocates an array of
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// strings.
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func (mp *MultipointExample) Reserve(ctx context.Context, state *framework.CycleState, pod *v1.Pod, nodeName string) *framework.Status {
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// Reserve is not called concurrently, and so we don't need to lock.
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mp.executionPoints = append(mp.executionPoints, "reserve")
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return nil
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}
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// Unreserve is the function invoked by the framework when any error happens
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// during "reserve" extension point or later. In this example, the Unreserve
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// method loses its reference to the string slice, allowing it to be garbage
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// collected, and thereby "unallocating" the reserved resources.
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func (mp *MultipointExample) Unreserve(ctx context.Context, state *framework.CycleState, pod *v1.Pod, nodeName string) {
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// Unlike Reserve, the Unreserve method may be called concurrently since
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// there is no guarantee that there will only one unreserve operation at any
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// given point in time (for example, during the binding cycle).
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mp.mu.Lock()
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defer mp.mu.Unlock()
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mp.executionPoints = nil
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}
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// PreBind is the function invoked by the framework at "prebind" extension
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// point.
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func (mp *MultipointExample) PreBind(ctx context.Context, state *framework.CycleState, pod *v1.Pod, nodeName string) *framework.Status {
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// PreBind could be called concurrently for different pods.
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mp.mu.Lock()
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defer mp.mu.Unlock()
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mp.executionPoints = append(mp.executionPoints, "pre-bind")
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if pod == nil {
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return framework.NewStatus(framework.Error, "pod must not be nil")
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}
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return nil
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}
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// New initializes a new plugin and returns it.
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func New(config *runtime.Unknown, _ framework.FrameworkHandle) (framework.Plugin, error) {
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if config == nil {
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klog.Error("MultipointExample configuration cannot be empty")
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return nil, fmt.Errorf("MultipointExample configuration cannot be empty")
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}
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mp := MultipointExample{}
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return &mp, nil
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}
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