228 lines
6.4 KiB
Go
228 lines
6.4 KiB
Go
/*
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Copyright 2015 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 tunneler
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import (
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"fmt"
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"io/ioutil"
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"net"
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"net/http"
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"net/url"
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"os"
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"sync/atomic"
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"time"
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"k8s.io/apimachinery/pkg/util/wait"
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"k8s.io/client-go/util/clock"
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"k8s.io/kubernetes/pkg/ssh"
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"k8s.io/kubernetes/pkg/util"
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"github.com/golang/glog"
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"github.com/prometheus/client_golang/prometheus"
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)
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type InstallSSHKey func(user string, data []byte) error
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type AddressFunc func() (addresses []string, err error)
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type Tunneler interface {
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Run(AddressFunc)
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Stop()
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Dial(net, addr string) (net.Conn, error)
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SecondsSinceSync() int64
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SecondsSinceSSHKeySync() int64
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}
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// TunnelSyncHealthChecker returns a health func that indicates if a tunneler is healthy.
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// It's compatible with healthz.NamedCheck
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func TunnelSyncHealthChecker(tunneler Tunneler) func(req *http.Request) error {
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return func(req *http.Request) error {
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if tunneler == nil {
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return nil
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}
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lag := tunneler.SecondsSinceSync()
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if lag > 600 {
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return fmt.Errorf("Tunnel sync is taking to long: %d", lag)
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}
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sshKeyLag := tunneler.SecondsSinceSSHKeySync()
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if sshKeyLag > 600 {
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return fmt.Errorf("SSHKey sync is taking to long: %d", sshKeyLag)
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}
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return nil
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}
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}
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type SSHTunneler struct {
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// Important: Since these two int64 fields are using sync/atomic, they have to be at the top of the struct due to a bug on 32-bit platforms
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// See: https://golang.org/pkg/sync/atomic/ for more information
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lastSync int64 // Seconds since Epoch
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lastSSHKeySync int64 // Seconds since Epoch
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SSHUser string
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SSHKeyfile string
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InstallSSHKey InstallSSHKey
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HealthCheckURL *url.URL
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tunnels *ssh.SSHTunnelList
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lastSyncMetric prometheus.GaugeFunc
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clock clock.Clock
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getAddresses AddressFunc
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stopChan chan struct{}
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}
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func New(sshUser, sshKeyfile string, healthCheckURL *url.URL, installSSHKey InstallSSHKey) Tunneler {
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return &SSHTunneler{
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SSHUser: sshUser,
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SSHKeyfile: sshKeyfile,
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InstallSSHKey: installSSHKey,
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HealthCheckURL: healthCheckURL,
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clock: clock.RealClock{},
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}
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}
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// Run establishes tunnel loops and returns
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func (c *SSHTunneler) Run(getAddresses AddressFunc) {
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if c.stopChan != nil {
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return
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}
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c.stopChan = make(chan struct{})
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// Save the address getter
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if getAddresses != nil {
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c.getAddresses = getAddresses
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}
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// Usernames are capped @ 32
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if len(c.SSHUser) > 32 {
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glog.Warning("SSH User is too long, truncating to 32 chars")
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c.SSHUser = c.SSHUser[0:32]
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}
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glog.Infof("Setting up proxy: %s %s", c.SSHUser, c.SSHKeyfile)
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// public keyfile is written last, so check for that.
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publicKeyFile := c.SSHKeyfile + ".pub"
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exists, err := util.FileExists(publicKeyFile)
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if err != nil {
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glog.Errorf("Error detecting if key exists: %v", err)
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} else if !exists {
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glog.Infof("Key doesn't exist, attempting to create")
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if err := generateSSHKey(c.SSHKeyfile, publicKeyFile); err != nil {
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glog.Errorf("Failed to create key pair: %v", err)
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}
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}
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c.tunnels = ssh.NewSSHTunnelList(c.SSHUser, c.SSHKeyfile, c.HealthCheckURL, c.stopChan)
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// Sync loop to ensure that the SSH key has been installed.
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c.lastSSHKeySync = c.clock.Now().Unix()
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c.installSSHKeySyncLoop(c.SSHUser, publicKeyFile)
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// Sync tunnelList w/ nodes.
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c.lastSync = c.clock.Now().Unix()
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c.nodesSyncLoop()
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}
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// Stop gracefully shuts down the tunneler
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func (c *SSHTunneler) Stop() {
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if c.stopChan != nil {
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close(c.stopChan)
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c.stopChan = nil
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}
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}
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func (c *SSHTunneler) Dial(net, addr string) (net.Conn, error) {
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return c.tunnels.Dial(net, addr)
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}
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func (c *SSHTunneler) SecondsSinceSync() int64 {
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now := c.clock.Now().Unix()
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then := atomic.LoadInt64(&c.lastSync)
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return now - then
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}
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func (c *SSHTunneler) SecondsSinceSSHKeySync() int64 {
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now := c.clock.Now().Unix()
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then := atomic.LoadInt64(&c.lastSSHKeySync)
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return now - then
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}
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func (c *SSHTunneler) installSSHKeySyncLoop(user, publicKeyfile string) {
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go wait.Until(func() {
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if c.InstallSSHKey == nil {
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glog.Error("Won't attempt to install ssh key: InstallSSHKey function is nil")
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return
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}
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key, err := ssh.ParsePublicKeyFromFile(publicKeyfile)
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if err != nil {
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glog.Errorf("Failed to load public key: %v", err)
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return
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}
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keyData, err := ssh.EncodeSSHKey(key)
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if err != nil {
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glog.Errorf("Failed to encode public key: %v", err)
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return
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}
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if err := c.InstallSSHKey(user, keyData); err != nil {
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glog.Errorf("Failed to install ssh key: %v", err)
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return
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}
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atomic.StoreInt64(&c.lastSSHKeySync, c.clock.Now().Unix())
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}, 5*time.Minute, c.stopChan)
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}
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// nodesSyncLoop lists nodes every 15 seconds, calling Update() on the TunnelList
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// each time (Update() is a noop if no changes are necessary).
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func (c *SSHTunneler) nodesSyncLoop() {
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// TODO (cjcullen) make this watch.
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go wait.Until(func() {
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addrs, err := c.getAddresses()
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glog.V(4).Infof("Calling update w/ addrs: %v", addrs)
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if err != nil {
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glog.Errorf("Failed to getAddresses: %v", err)
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}
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c.tunnels.Update(addrs)
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atomic.StoreInt64(&c.lastSync, c.clock.Now().Unix())
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}, 15*time.Second, c.stopChan)
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}
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func generateSSHKey(privateKeyfile, publicKeyfile string) error {
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private, public, err := ssh.GenerateKey(2048)
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if err != nil {
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return err
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}
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// If private keyfile already exists, we must have only made it halfway
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// through last time, so delete it.
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exists, err := util.FileExists(privateKeyfile)
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if err != nil {
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glog.Errorf("Error detecting if private key exists: %v", err)
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} else if exists {
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glog.Infof("Private key exists, but public key does not")
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if err := os.Remove(privateKeyfile); err != nil {
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glog.Errorf("Failed to remove stale private key: %v", err)
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}
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}
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if err := ioutil.WriteFile(privateKeyfile, ssh.EncodePrivateKey(private), 0600); err != nil {
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return err
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}
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publicKeyBytes, err := ssh.EncodePublicKey(public)
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if err != nil {
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return err
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}
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if err := ioutil.WriteFile(publicKeyfile+".tmp", publicKeyBytes, 0600); err != nil {
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return err
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}
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return os.Rename(publicKeyfile+".tmp", publicKeyfile)
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}
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