-
Notifications
You must be signed in to change notification settings - Fork 39.3k
/
admission.go
255 lines (220 loc) · 7.81 KB
/
admission.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
/*
Copyright 2016 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package podnodeselector
import (
"fmt"
"io"
"reflect"
"k8s.io/klog"
corev1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/apimachinery/pkg/util/yaml"
"k8s.io/apiserver/pkg/admission"
genericadmissioninitializer "k8s.io/apiserver/pkg/admission/initializer"
"k8s.io/client-go/informers"
"k8s.io/client-go/kubernetes"
corev1listers "k8s.io/client-go/listers/core/v1"
api "k8s.io/kubernetes/pkg/apis/core"
)
// The annotation key scheduler.alpha.kubernetes.io/node-selector is for assigning
// node selectors labels to namespaces
var NamespaceNodeSelectors = []string{"scheduler.alpha.kubernetes.io/node-selector"}
const PluginName = "PodNodeSelector"
// Register registers a plugin
func Register(plugins *admission.Plugins) {
plugins.Register(PluginName, func(config io.Reader) (admission.Interface, error) {
// TODO move this to a versioned configuration file format.
pluginConfig := readConfig(config)
plugin := NewPodNodeSelector(pluginConfig.PodNodeSelectorPluginConfig)
return plugin, nil
})
}
// podNodeSelector is an implementation of admission.Interface.
type podNodeSelector struct {
*admission.Handler
client kubernetes.Interface
namespaceLister corev1listers.NamespaceLister
// global default node selector and namespace whitelists in a cluster.
clusterNodeSelectors map[string]string
}
var _ = genericadmissioninitializer.WantsExternalKubeClientSet(&podNodeSelector{})
var _ = genericadmissioninitializer.WantsExternalKubeInformerFactory(&podNodeSelector{})
type pluginConfig struct {
PodNodeSelectorPluginConfig map[string]string
}
// readConfig reads default value of clusterDefaultNodeSelector
// from the file provided with --admission-control-config-file
// If the file is not supplied, it defaults to ""
// The format in a file:
// podNodeSelectorPluginConfig:
// clusterDefaultNodeSelector: <node-selectors-labels>
// namespace1: <node-selectors-labels>
// namespace2: <node-selectors-labels>
func readConfig(config io.Reader) *pluginConfig {
defaultConfig := &pluginConfig{}
if config == nil || reflect.ValueOf(config).IsNil() {
return defaultConfig
}
d := yaml.NewYAMLOrJSONDecoder(config, 4096)
for {
if err := d.Decode(defaultConfig); err != nil {
if err != io.EOF {
continue
}
}
break
}
return defaultConfig
}
// Admit enforces that pod and its namespace node label selectors matches at least a node in the cluster.
func (p *podNodeSelector) Admit(a admission.Attributes, o admission.ObjectInterfaces) error {
if shouldIgnore(a) {
return nil
}
if !p.WaitForReady() {
return admission.NewForbidden(a, fmt.Errorf("not yet ready to handle request"))
}
resource := a.GetResource().GroupResource()
pod := a.GetObject().(*api.Pod)
namespaceNodeSelector, err := p.getNamespaceNodeSelectorMap(a.GetNamespace())
if err != nil {
return err
}
if labels.Conflicts(namespaceNodeSelector, labels.Set(pod.Spec.NodeSelector)) {
return errors.NewForbidden(resource, pod.Name, fmt.Errorf("pod node label selector conflicts with its namespace node label selector"))
}
// Merge pod node selector = namespace node selector + current pod node selector
// second selector wins
podNodeSelectorLabels := labels.Merge(namespaceNodeSelector, pod.Spec.NodeSelector)
pod.Spec.NodeSelector = map[string]string(podNodeSelectorLabels)
return p.Validate(a, o)
}
// Validate ensures that the pod node selector is allowed
func (p *podNodeSelector) Validate(a admission.Attributes, o admission.ObjectInterfaces) error {
if shouldIgnore(a) {
return nil
}
if !p.WaitForReady() {
return admission.NewForbidden(a, fmt.Errorf("not yet ready to handle request"))
}
resource := a.GetResource().GroupResource()
pod := a.GetObject().(*api.Pod)
namespaceNodeSelector, err := p.getNamespaceNodeSelectorMap(a.GetNamespace())
if err != nil {
return err
}
if labels.Conflicts(namespaceNodeSelector, labels.Set(pod.Spec.NodeSelector)) {
return errors.NewForbidden(resource, pod.Name, fmt.Errorf("pod node label selector conflicts with its namespace node label selector"))
}
// whitelist verification
whitelist, err := labels.ConvertSelectorToLabelsMap(p.clusterNodeSelectors[a.GetNamespace()])
if err != nil {
return err
}
if !labels.AreLabelsInWhiteList(pod.Spec.NodeSelector, whitelist) {
return errors.NewForbidden(resource, pod.Name, fmt.Errorf("pod node label selector labels conflict with its namespace whitelist"))
}
return nil
}
func (p *podNodeSelector) getNamespaceNodeSelectorMap(namespaceName string) (labels.Set, error) {
namespace, err := p.namespaceLister.Get(namespaceName)
if errors.IsNotFound(err) {
namespace, err = p.defaultGetNamespace(namespaceName)
if err != nil {
if errors.IsNotFound(err) {
return nil, err
}
return nil, errors.NewInternalError(err)
}
} else if err != nil {
return nil, errors.NewInternalError(err)
}
return p.getNodeSelectorMap(namespace)
}
func shouldIgnore(a admission.Attributes) bool {
resource := a.GetResource().GroupResource()
if resource != api.Resource("pods") {
return true
}
if a.GetSubresource() != "" {
// only run the checks below on pods proper and not subresources
return true
}
_, ok := a.GetObject().(*api.Pod)
if !ok {
klog.Errorf("expected pod but got %s", a.GetKind().Kind)
return true
}
return false
}
func NewPodNodeSelector(clusterNodeSelectors map[string]string) *podNodeSelector {
return &podNodeSelector{
Handler: admission.NewHandler(admission.Create),
clusterNodeSelectors: clusterNodeSelectors,
}
}
func (a *podNodeSelector) SetExternalKubeClientSet(client kubernetes.Interface) {
a.client = client
}
func (p *podNodeSelector) SetExternalKubeInformerFactory(f informers.SharedInformerFactory) {
namespaceInformer := f.Core().V1().Namespaces()
p.namespaceLister = namespaceInformer.Lister()
p.SetReadyFunc(namespaceInformer.Informer().HasSynced)
}
func (p *podNodeSelector) ValidateInitialization() error {
if p.namespaceLister == nil {
return fmt.Errorf("missing namespaceLister")
}
if p.client == nil {
return fmt.Errorf("missing client")
}
return nil
}
func (p *podNodeSelector) defaultGetNamespace(name string) (*corev1.Namespace, error) {
namespace, err := p.client.CoreV1().Namespaces().Get(name, metav1.GetOptions{})
if err != nil {
return nil, fmt.Errorf("namespace %s does not exist", name)
}
return namespace, nil
}
func (p *podNodeSelector) getNodeSelectorMap(namespace *corev1.Namespace) (labels.Set, error) {
selector := labels.Set{}
labelsMap := labels.Set{}
var err error
found := false
if len(namespace.ObjectMeta.Annotations) > 0 {
for _, annotation := range NamespaceNodeSelectors {
if ns, ok := namespace.ObjectMeta.Annotations[annotation]; ok {
labelsMap, err = labels.ConvertSelectorToLabelsMap(ns)
if err != nil {
return labels.Set{}, err
}
if labels.Conflicts(selector, labelsMap) {
nsName := namespace.ObjectMeta.Name
return labels.Set{}, fmt.Errorf("%s annotations' node label selectors conflict", nsName)
}
selector = labels.Merge(selector, labelsMap)
found = true
}
}
}
if !found {
selector, err = labels.ConvertSelectorToLabelsMap(p.clusterNodeSelectors["clusterDefaultNodeSelector"])
if err != nil {
return labels.Set{}, err
}
}
return selector, nil
}