-
Notifications
You must be signed in to change notification settings - Fork 39.2k
/
bootstrap.go
209 lines (189 loc) · 7.17 KB
/
bootstrap.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
/*
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 bootstrap
import (
"fmt"
"os"
"path/filepath"
"time"
"github.com/golang/glog"
"k8s.io/apimachinery/pkg/types"
utilruntime "k8s.io/apimachinery/pkg/util/runtime"
certificates "k8s.io/client-go/kubernetes/typed/certificates/v1beta1"
restclient "k8s.io/client-go/rest"
"k8s.io/client-go/tools/clientcmd"
clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
"k8s.io/client-go/transport"
certutil "k8s.io/client-go/util/cert"
"k8s.io/client-go/util/certificate/csr"
)
const (
defaultKubeletClientCertificateFile = "kubelet-client.crt"
defaultKubeletClientKeyFile = "kubelet-client.key"
)
// LoadClientCert requests a client cert for kubelet if the kubeconfigPath file does not exist.
// The kubeconfig at bootstrapPath is used to request a client certificate from the API server.
// On success, a kubeconfig file referencing the generated key and obtained certificate is written to kubeconfigPath.
// The certificate and key file are stored in certDir.
func LoadClientCert(kubeconfigPath string, bootstrapPath string, certDir string, nodeName types.NodeName) error {
// Short-circuit if the kubeconfig file exists and is valid.
ok, err := verifyBootstrapClientConfig(kubeconfigPath)
if err != nil {
return err
}
if ok {
glog.V(2).Infof("Kubeconfig %s exists and is valid, skipping bootstrap", kubeconfigPath)
return nil
}
glog.V(2).Info("Using bootstrap kubeconfig to generate TLS client cert, key and kubeconfig file")
bootstrapClientConfig, err := loadRESTClientConfig(bootstrapPath)
if err != nil {
return fmt.Errorf("unable to load bootstrap kubeconfig: %v", err)
}
bootstrapClient, err := certificates.NewForConfig(bootstrapClientConfig)
if err != nil {
return fmt.Errorf("unable to create certificates signing request client: %v", err)
}
success := false
// Get the private key.
keyPath, err := filepath.Abs(filepath.Join(certDir, defaultKubeletClientKeyFile))
if err != nil {
return fmt.Errorf("unable to build bootstrap key path: %v", err)
}
// If we are unable to generate a CSR, we remove our key file and start fresh.
// This method is used before enabling client rotation and so we must ensure we
// can make forward progress if we crash and exit when a CSR exists but the cert
// it is signed for has expired.
defer func() {
if !success {
if err := os.Remove(keyPath); err != nil && !os.IsNotExist(err) {
glog.Warningf("Cannot clean up the key file %q: %v", keyPath, err)
}
}
}()
keyData, _, err := certutil.LoadOrGenerateKeyFile(keyPath)
if err != nil {
return err
}
// Get the cert.
certPath, err := filepath.Abs(filepath.Join(certDir, defaultKubeletClientCertificateFile))
if err != nil {
return fmt.Errorf("unable to build bootstrap client cert path: %v", err)
}
defer func() {
if !success {
if err := os.Remove(certPath); err != nil && !os.IsNotExist(err) {
glog.Warningf("Cannot clean up the cert file %q: %v", certPath, err)
}
}
}()
certData, err := csr.RequestNodeCertificate(bootstrapClient.CertificateSigningRequests(), keyData, nodeName)
if err != nil {
return err
}
if err := certutil.WriteCert(certPath, certData); err != nil {
return err
}
// Get the CA data from the bootstrap client config.
caFile, caData := bootstrapClientConfig.CAFile, []byte{}
if len(caFile) == 0 {
caData = bootstrapClientConfig.CAData
}
// Build resulting kubeconfig.
kubeconfigData := clientcmdapi.Config{
// Define a cluster stanza based on the bootstrap kubeconfig.
Clusters: map[string]*clientcmdapi.Cluster{"default-cluster": {
Server: bootstrapClientConfig.Host,
InsecureSkipTLSVerify: bootstrapClientConfig.Insecure,
CertificateAuthority: caFile,
CertificateAuthorityData: caData,
}},
// Define auth based on the obtained client cert.
AuthInfos: map[string]*clientcmdapi.AuthInfo{"default-auth": {
ClientCertificate: certPath,
ClientKey: keyPath,
}},
// Define a context that connects the auth info and cluster, and set it as the default
Contexts: map[string]*clientcmdapi.Context{"default-context": {
Cluster: "default-cluster",
AuthInfo: "default-auth",
Namespace: "default",
}},
CurrentContext: "default-context",
}
// Marshal to disk
if err := clientcmd.WriteToFile(kubeconfigData, kubeconfigPath); err != nil {
return err
}
success = true
return nil
}
func loadRESTClientConfig(kubeconfig string) (*restclient.Config, error) {
// Load structured kubeconfig data from the given path.
loader := &clientcmd.ClientConfigLoadingRules{ExplicitPath: kubeconfig}
loadedConfig, err := loader.Load()
if err != nil {
return nil, err
}
// Flatten the loaded data to a particular restclient.Config based on the current context.
return clientcmd.NewNonInteractiveClientConfig(
*loadedConfig,
loadedConfig.CurrentContext,
&clientcmd.ConfigOverrides{},
loader,
).ClientConfig()
}
// verifyBootstrapClientConfig checks the provided kubeconfig to see if it has a valid
// client certificate. It returns true if the kubeconfig is valid, or an error if bootstrapping
// should stop immediately.
func verifyBootstrapClientConfig(kubeconfigPath string) (bool, error) {
_, err := os.Stat(kubeconfigPath)
if os.IsNotExist(err) {
return false, nil
}
if err != nil {
return false, fmt.Errorf("error reading existing bootstrap kubeconfig %s: %v", kubeconfigPath, err)
}
bootstrapClientConfig, err := loadRESTClientConfig(kubeconfigPath)
if err != nil {
utilruntime.HandleError(fmt.Errorf("Unable to read existing bootstrap client config: %v", err))
return false, nil
}
transportConfig, err := bootstrapClientConfig.TransportConfig()
if err != nil {
utilruntime.HandleError(fmt.Errorf("Unable to load transport configuration from existing bootstrap client config: %v", err))
return false, nil
}
// has side effect of populating transport config data fields
if _, err := transport.TLSConfigFor(transportConfig); err != nil {
utilruntime.HandleError(fmt.Errorf("Unable to load TLS configuration from existing bootstrap client config: %v", err))
return false, nil
}
certs, err := certutil.ParseCertsPEM(transportConfig.TLS.CertData)
if err != nil {
utilruntime.HandleError(fmt.Errorf("Unable to load TLS certificates from existing bootstrap client config: %v", err))
return false, nil
}
if len(certs) == 0 {
utilruntime.HandleError(fmt.Errorf("Unable to read TLS certificates from existing bootstrap client config: %v", err))
return false, nil
}
now := time.Now()
for _, cert := range certs {
if now.After(cert.NotAfter) {
utilruntime.HandleError(fmt.Errorf("Part of the existing bootstrap client certificate is expired: %s", cert.NotAfter))
return false, nil
}
}
return true, nil
}