mirror of https://github.com/k3s-io/k3s
96 lines
2.5 KiB
Go
96 lines
2.5 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 nodetaint
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import (
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"context"
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"fmt"
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"io"
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v1 "k8s.io/api/core/v1"
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"k8s.io/apiserver/pkg/admission"
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api "k8s.io/kubernetes/pkg/apis/core"
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)
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const (
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// PluginName is the name of the plugin.
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PluginName = "TaintNodesByCondition"
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)
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// Register registers a plugin
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func Register(plugins *admission.Plugins) {
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plugins.Register(PluginName, func(config io.Reader) (admission.Interface, error) {
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return NewPlugin(), nil
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})
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}
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// NewPlugin creates a new NodeTaint admission plugin.
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// This plugin identifies requests from nodes
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func NewPlugin() *Plugin {
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return &Plugin{
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Handler: admission.NewHandler(admission.Create),
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}
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}
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// Plugin holds state for and implements the admission plugin.
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type Plugin struct {
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*admission.Handler
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}
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var (
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_ = admission.Interface(&Plugin{})
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)
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var (
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nodeResource = api.Resource("nodes")
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)
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// Admit is the main function that checks node identity and adds taints as needed.
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func (p *Plugin) Admit(ctx context.Context, a admission.Attributes, o admission.ObjectInterfaces) error {
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// Our job is just to taint nodes.
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if a.GetResource().GroupResource() != nodeResource || a.GetSubresource() != "" {
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return nil
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}
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node, ok := a.GetObject().(*api.Node)
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if !ok {
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return admission.NewForbidden(a, fmt.Errorf("unexpected type %T", a.GetObject()))
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}
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// Taint node with NotReady taint at creation. This is needed to make sure
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// that nodes are added to the cluster with the NotReady taint. Otherwise,
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// a new node may receive the taint with some delay causing pods to be
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// scheduled on a not-ready node. Node controller will remove the taint
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// when the node becomes ready.
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addNotReadyTaint(node)
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return nil
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}
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func addNotReadyTaint(node *api.Node) {
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notReadyTaint := api.Taint{
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Key: v1.TaintNodeNotReady,
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Effect: api.TaintEffectNoSchedule,
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}
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for _, taint := range node.Spec.Taints {
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if taint.MatchTaint(notReadyTaint) {
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// the taint already exists.
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return
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}
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}
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node.Spec.Taints = append(node.Spec.Taints, notReadyTaint)
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}
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