refactor ssh key generation

api/v1alpha3/azuremachine_default.go

@@ -17,27 +17,22 @@ limitations under the License.
 package v1alpha3
 
 import (
-	"crypto/rand"
-	"crypto/rsa"
 	"encoding/base64"
 
-	"github.com/pkg/errors"
 	"golang.org/x/crypto/ssh"
+
+	utilSSH "sigs.k8s.io/cluster-api-provider-azure/util/ssh"
 )
 
 // SetDefaultSSHPublicKey sets the default SSHPublicKey for an AzureMachine
 func (m *AzureMachine) SetDefaultSSHPublicKey() error {
 	sshKeyData := m.Spec.SSHPublicKey
 	if sshKeyData == "" {
-		privateKey, perr := rsa.GenerateKey(rand.Reader, 2048)
-		if perr != nil {
-			return errors.Wrap(perr, "Failed to generate private key")
+		_, publicRsaKey, err := utilSSH.GenerateSSHKey()
+		if err != nil {
+			return err
 		}
 
-		publicRsaKey, perr := ssh.NewPublicKey(&privateKey.PublicKey)
-		if perr != nil {
-			return errors.Wrap(perr, "Failed to generate public key")
-		}
 		m.Spec.SSHPublicKey = base64.StdEncoding.EncodeToString(ssh.MarshalAuthorizedKey(publicRsaKey))
 	}
 

exp/api/v1alpha3/azuremachinepool_default.go

@@ -17,27 +17,22 @@ limitations under the License.
 package v1alpha3
 
 import (
-	"crypto/rand"
-	"crypto/rsa"
 	"encoding/base64"
 
-	"github.com/pkg/errors"
 	"golang.org/x/crypto/ssh"
+
+	utilSSH "sigs.k8s.io/cluster-api-provider-azure/util/ssh"
 )
 
 // SetDefaultSSHPublicKey sets the default SSHPublicKey for an AzureMachinePool
 func (amp *AzureMachinePool) SetDefaultSSHPublicKey() error {
 	sshKeyData := amp.Spec.Template.SSHPublicKey
 	if sshKeyData == "" {
-		privateKey, perr := rsa.GenerateKey(rand.Reader, 2048)
-		if perr != nil {
-			return errors.Wrap(perr, "Failed to generate private key")
+		_, publicRsaKey, err := utilSSH.GenerateSSHKey()
+		if err != nil {
+			return err
 		}
 
-		publicRsaKey, perr := ssh.NewPublicKey(&privateKey.PublicKey)
-		if perr != nil {
-			return errors.Wrap(perr, "Failed to generate public key")
-		}
 		amp.Spec.Template.SSHPublicKey = base64.StdEncoding.EncodeToString(ssh.MarshalAuthorizedKey(publicRsaKey))
 	}
 

exp/api/v1alpha3/azuremanagedcontrolplane_default.go

@@ -17,27 +17,22 @@ limitations under the License.
 package v1alpha3
 
 import (
-	"crypto/rand"
-	"crypto/rsa"
 	"encoding/base64"
 
-	"github.com/pkg/errors"
 	"golang.org/x/crypto/ssh"
+
+	utilSSH "sigs.k8s.io/cluster-api-provider-azure/util/ssh"
 )
 
 // SetDefaultSSHPublicKey sets the default SSHPublicKey for an AzureManagedControlPlane
 func (r *AzureManagedControlPlane) SetDefaultSSHPublicKey() error {
 	sshKeyData := r.Spec.SSHPublicKey
 	if sshKeyData == "" {
-		privateKey, perr := rsa.GenerateKey(rand.Reader, 2048)
-		if perr != nil {
-			return errors.Wrap(perr, "Failed to generate private key")
+		_, publicRsaKey, err := utilSSH.GenerateSSHKey()
+		if err != nil {
+			return err
 		}
 
-		publicRsaKey, perr := ssh.NewPublicKey(&privateKey.PublicKey)
-		if perr != nil {
-			return errors.Wrap(perr, "Failed to generate public key")
-		}
 		r.Spec.SSHPublicKey = base64.StdEncoding.EncodeToString(ssh.MarshalAuthorizedKey(publicRsaKey))
 	}
 

templates/flavors/aks/cluster-template.yaml

@@ -33,7 +33,7 @@ spec:
   location: "${AZURE_LOCATION}"
   defaultPoolRef:
     name: "agentpool0"
-  sshPublicKey: "${AZURE_SSH_PUBLIC_KEY_B64}"
+  sshPublicKey: ${AZURE_SSH_PUBLIC_KEY_B64:=""}
   version: "${KUBERNETES_VERSION}"
 ---
 # Due to the nature of managed Kubernetes and the control plane implementation,

util/ssh/ssh.go

@@ -0,0 +1,40 @@
+/*
+Copyright 2020 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 ssh
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+
+	"github.com/pkg/errors"
+	"golang.org/x/crypto/ssh"
+)
+
+// GenerateSSHKey generates a private and public ssh key
+func GenerateSSHKey() (*rsa.PrivateKey, ssh.PublicKey, error) {
+	privateKey, perr := rsa.GenerateKey(rand.Reader, 2048)
+	if perr != nil {
+		return nil, nil, errors.Wrap(perr, "Failed to generate private key")
+	}
+
+	publicRsaKey, perr := ssh.NewPublicKey(&privateKey.PublicKey)
+	if perr != nil {
+		return nil, nil, errors.Wrap(perr, "Failed to generate public key")
+	}
+
+	return privateKey, publicRsaKey, nil
+}

util/ssh/ssh_test.go

@@ -0,0 +1,32 @@
+/*
+Copyright 2020 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 ssh
+
+import (
+	"testing"
+
+	. "github.com/onsi/gomega"
+)
+
+func TestGenerateSSHKey(t *testing.T) {
+	g := NewWithT(t)
+
+	privateKey, publicKey, err := GenerateSSHKey()
+	g.Expect(err).NotTo(HaveOccurred())
+	g.Expect(privateKey).NotTo(BeNil())
+	g.Expect(publicKey).NotTo(BeNil())
+}