// MaybeGenerateServingCerts generates serving certificates if requested and needed.
func (c *Config) MaybeGenerateServingCerts(alternateIPs ...net.IP) error {
// It would be nice to set a fqdn subject alt name, but only the kubelets know, the apiserver is clueless
// alternateDNS = append(alternateDNS, "kubernetes.default.svc.CLUSTER.DNS.NAME")
if c.SecureServingInfo != nil && c.SecureServingInfo.ServerCert.Generate {
canReadCertAndKey, err := certutil.CanReadCertAndKey(c.SecureServingInfo.ServerCert.CertFile, c.SecureServingInfo.ServerCert.KeyFile)
if err != nil {
return err
}
if canReadCertAndKey {
return nil
}
// TODO (cjcullen): Is ClusterIP the right address to sign a cert with?
alternateDNS := []string{"kubernetes.default.svc", "kubernetes.default", "kubernetes", "localhost"}
if cert, key, err := certutil.GenerateSelfSignedCertKey(c.PublicAddress.String(), alternateIPs, alternateDNS); err != nil {
return fmt.Errorf("unable to generate self signed cert: %v", err)
} else {
if err := certutil.WriteCert(c.SecureServingInfo.ServerCert.CertFile, cert); err != nil {
return err
}
if err := certutil.WriteKey(c.SecureServingInfo.ServerCert.KeyFile, key); err != nil {
return err
}
glog.Infof("Generated self-signed cert (%s, %s)", c.SecureServingInfo.ServerCert.CertFile, c.SecureServingInfo.ServerCert.KeyFile)
}
}
return nil
}
func writeKeysAndCert(pkiPath string, name string, key *rsa.PrivateKey, cert *x509.Certificate) error {
var (
publicKeyPath = path.Join(pkiPath, fmt.Sprintf("%s-pub.pem", name))
privateKeyPath = path.Join(pkiPath, fmt.Sprintf("%s-key.pem", name))
certificatePath = path.Join(pkiPath, fmt.Sprintf("%s.pem", name))
)
if key != nil {
if err := certutil.WriteKey(privateKeyPath, certutil.EncodePrivateKeyPEM(key)); err != nil {
return fmt.Errorf("unable to write private key file (%q) [%v]", privateKeyPath, err)
}
if pubKey, err := certutil.EncodePublicKeyPEM(&key.PublicKey); err == nil {
if err := certutil.WriteKey(publicKeyPath, pubKey); err != nil {
return fmt.Errorf("unable to write public key file (%q) [%v]", publicKeyPath, err)
}
} else {
return fmt.Errorf("unable to encode public key to PEM [%v]", err)
}
}
if cert != nil {
if err := certutil.WriteCert(certificatePath, certutil.EncodeCertPEM(cert)); err != nil {
return fmt.Errorf("unable to write certificate file (%q) [%v]", certificatePath, err)
}
}
return nil
}
// InitializeTLS checks for a configured TLSCertFile and TLSPrivateKeyFile: if unspecified a new self-signed
// certificate and key file are generated. Returns a configured server.TLSOptions object.
func InitializeTLS(kc *componentconfig.KubeletConfiguration) (*server.TLSOptions, error) {
if kc.TLSCertFile == "" && kc.TLSPrivateKeyFile == "" {
kc.TLSCertFile = path.Join(kc.CertDirectory, "kubelet.crt")
kc.TLSPrivateKeyFile = path.Join(kc.CertDirectory, "kubelet.key")
canReadCertAndKey, err := certutil.CanReadCertAndKey(kc.TLSCertFile, kc.TLSPrivateKeyFile)
if err != nil {
return nil, err
}
if !canReadCertAndKey {
cert, key, err := certutil.GenerateSelfSignedCertKey(nodeutil.GetHostname(kc.HostnameOverride), nil, nil)
if err != nil {
return nil, fmt.Errorf("unable to generate self signed cert: %v", err)
}
if err := certutil.WriteCert(kc.TLSCertFile, cert); err != nil {
return nil, err
}
if err := certutil.WriteKey(kc.TLSPrivateKeyFile, key); err != nil {
return nil, err
}
glog.V(4).Infof("Using self-signed cert (%s, %s)", kc.TLSCertFile, kc.TLSPrivateKeyFile)
}
}
tlsOptions := &server.TLSOptions{
Config: &tls.Config{
// Can't use SSLv3 because of POODLE and BEAST
// Can't use TLSv1.0 because of POODLE and BEAST using CBC cipher
// Can't use TLSv1.1 because of RC4 cipher usage
MinVersion: tls.VersionTLS12,
},
CertFile: kc.TLSCertFile,
KeyFile: kc.TLSPrivateKeyFile,
}
if len(kc.Authentication.X509.ClientCAFile) > 0 {
clientCAs, err := cert.NewPool(kc.Authentication.X509.ClientCAFile)
if err != nil {
return nil, fmt.Errorf("unable to load client CA file %s: %v", kc.Authentication.X509.ClientCAFile, err)
}
// Specify allowed CAs for client certificates
tlsOptions.Config.ClientCAs = clientCAs
// Populate PeerCertificates in requests, but don't reject connections without verified certificates
tlsOptions.Config.ClientAuth = tls.RequestClientCert
}
return tlsOptions, nil
}
func (s *SecureServingOptions) MaybeDefaultWithSelfSignedCerts(publicAddress string, alternateIPs ...net.IP) error {
if s == nil {
return nil
}
keyCert := &s.ServerCert.CertKey
if s.ServingOptions.BindPort == 0 || len(keyCert.CertFile) != 0 || len(keyCert.KeyFile) != 0 {
return nil
}
keyCert.CertFile = path.Join(s.ServerCert.CertDirectory, s.ServerCert.PairName+".crt")
keyCert.KeyFile = path.Join(s.ServerCert.CertDirectory, s.ServerCert.PairName+".key")
canReadCertAndKey, err := certutil.CanReadCertAndKey(keyCert.CertFile, keyCert.KeyFile)
if err != nil {
return err
}
if !canReadCertAndKey {
// TODO: It would be nice to set a fqdn subject alt name, but only the kubelets know, the apiserver is clueless
// alternateDNS = append(alternateDNS, "kubernetes.default.svc.CLUSTER.DNS.NAME")
// TODO (cjcullen): Is ClusterIP the right address to sign a cert with?
alternateDNS := []string{"kubernetes.default.svc", "kubernetes.default", "kubernetes"}
// add either the bind address or localhost to the valid alternates
bindIP := s.ServingOptions.BindAddress.String()
if bindIP == "0.0.0.0" {
alternateDNS = append(alternateDNS, "localhost")
} else {
alternateIPs = append(alternateIPs, s.ServingOptions.BindAddress)
}
if cert, key, err := certutil.GenerateSelfSignedCertKey(publicAddress, alternateIPs, alternateDNS); err != nil {
return fmt.Errorf("unable to generate self signed cert: %v", err)
} else {
if err := certutil.WriteCert(keyCert.CertFile, cert); err != nil {
return err
}
if err := certutil.WriteKey(keyCert.KeyFile, key); err != nil {
return err
}
glog.Infof("Generated self-signed cert (%s, %s)", keyCert.CertFile, keyCert.KeyFile)
}
}
return nil
}
// bootstrapClientCert 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 bootstrapClientCert(kubeconfigPath string, bootstrapPath string, certDir string, nodeName types.NodeName) error {
// Short-circuit if the kubeconfig file already exists.
// TODO: inspect the kubeconfig, ensure a rest client can be built from it, verify client cert expiration, etc.
_, err := os.Stat(kubeconfigPath)
if err == nil {
glog.V(2).Infof("Kubeconfig %s exists, skipping bootstrap", kubeconfigPath)
return nil
}
if !os.IsNotExist(err) {
glog.Errorf("Error reading kubeconfig %s, skipping bootstrap: %v", kubeconfigPath, err)
return err
}
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 := unversionedcertificates.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)
}
keyData, generatedKeyFile, err := loadOrGenerateKeyFile(keyPath)
if err != nil {
return err
}
if generatedKeyFile {
defer func() {
if !success {
if err := os.Remove(keyPath); err != nil {
glog.Warningf("Cannot clean up the key file %q: %v", keyPath, 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)
}
certData, err := csr.RequestNodeCertificate(bootstrapClient.CertificateSigningRequests(), keyData, nodeName)
if err != nil {
return err
}
if err := certutil.WriteCert(certPath, certData); err != nil {
return err
}
defer func() {
if !success {
if err := os.Remove(certPath); err != nil {
glog.Warningf("Cannot clean up the cert file %q: %v", certPath, 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
}