Merge branch 'ansible-provisioner' of https://github.com/bhcleek/packer into f-ansible

This commit is contained in:
Chris Bednarski 2016-01-28 15:16:54 -08:00
commit 15f99a4aee
8 changed files with 1037 additions and 5 deletions

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package main
import (
"github.com/mitchellh/packer/packer/plugin"
"github.com/mitchellh/packer/provisioner/ansible"
)
func main() {
server, err := plugin.Server()
if err != nil {
panic(err)
}
server.RegisterProvisioner(new(ansible.Provisioner))
server.Serve()
}

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package main

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package ansible
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"io"
"net"
"github.com/mitchellh/packer/packer"
"golang.org/x/crypto/ssh"
)
type adapter struct {
done <-chan struct{}
l net.Listener
config *ssh.ServerConfig
sftpCmd string
ui packer.Ui
comm packer.Communicator
}
func newAdapter(done <-chan struct{}, l net.Listener, config *ssh.ServerConfig, sftpCmd string, ui packer.Ui, comm packer.Communicator) *adapter {
return &adapter{
done: done,
l: l,
config: config,
sftpCmd: sftpCmd,
ui: ui,
comm: comm,
}
}
func (c *adapter) Serve() {
c.ui.Say(fmt.Sprintf("SSH proxy: serving on %s", c.l.Addr()))
for {
// Accept will return if either the underlying connection is closed or if a connection is made.
// after returning, check to see if c.done can be received. If so, then Accept() returned because
// the connection has been closed.
conn, err := c.l.Accept()
select {
case <-c.done:
return
default:
if err != nil {
c.ui.Error(fmt.Sprintf("listen.Accept failed: %v", err))
continue
}
go func(conn net.Conn) {
if err := c.Handle(conn, c.ui); err != nil {
c.ui.Error(err.Error())
}
}(conn)
}
}
}
func (c *adapter) Handle(conn net.Conn, ui packer.Ui) error {
c.ui.Message("SSH proxy: accepted connection")
_, chans, reqs, err := ssh.NewServerConn(conn, c.config)
if err != nil {
return errors.New("failed to handshake")
}
// discard all global requests
go ssh.DiscardRequests(reqs)
// Service the incoming NewChannels
for newChannel := range chans {
if newChannel.ChannelType() != "session" {
newChannel.Reject(ssh.UnknownChannelType, "unknown channel type")
continue
}
go func(ch ssh.NewChannel) {
if err := c.handleSession(ch); err != nil {
c.ui.Error(err.Error())
}
}(newChannel)
}
return nil
}
func (c *adapter) handleSession(newChannel ssh.NewChannel) error {
channel, requests, err := newChannel.Accept()
if err != nil {
return err
}
defer channel.Close()
done := make(chan struct{})
// Sessions have requests such as "pty-req", "shell", "env", and "exec".
// see RFC 4254, section 6
go func(in <-chan *ssh.Request) {
env := make([]envRequestPayload, 4)
for req := range in {
switch req.Type {
case "pty-req":
// accept pty-req requests, but don't actually do anything. Necessary for OpenSSH and sudo.
req.Reply(true, nil)
case "env":
req.Reply(true, nil)
req, err := newEnvRequest(req)
if err != nil {
c.ui.Error(err.Error())
continue
}
env = append(env, req.Payload)
case "exec":
req.Reply(true, nil)
req, err := newExecRequest(req)
if err != nil {
c.ui.Error(err.Error())
close(done)
continue
}
if len(req.Payload) > 0 {
cmd := &packer.RemoteCmd{
Stdin: channel,
Stdout: channel,
Stderr: channel.Stderr(),
Command: string(req.Payload),
}
if err := c.comm.Start(cmd); err != nil {
c.ui.Error(err.Error())
close(done)
return
}
go func(cmd *packer.RemoteCmd, channel ssh.Channel) {
cmd.Wait()
exitStatus := make([]byte, 4)
binary.BigEndian.PutUint32(exitStatus, uint32(cmd.ExitStatus))
channel.SendRequest("exit-status", false, exitStatus)
close(done)
}(cmd, channel)
}
case "subsystem":
req, err := newSubsystemRequest(req)
if err != nil {
c.ui.Error(err.Error())
continue
}
switch req.Payload {
case "sftp":
c.ui.Say("starting sftp subsystem")
req.Reply(true, nil)
sftpCmd := c.sftpCmd
if len(sftpCmd) == 0 {
sftpCmd = "/usr/lib/sftp-server -e"
}
cmd := &packer.RemoteCmd{
Stdin: channel,
Stdout: channel,
Stderr: channel.Stderr(),
Command: sftpCmd,
}
if err := c.comm.Start(cmd); err != nil {
c.ui.Error(err.Error())
}
go func() {
cmd.Wait()
close(done)
}()
default:
req.Reply(false, nil)
}
default:
c.ui.Message(fmt.Sprintf("rejecting %s request", req.Type))
req.Reply(false, nil)
}
}
}(requests)
<-done
return nil
}
func (c *adapter) Shutdown() {
c.l.Close()
}
type envRequest struct {
*ssh.Request
Payload envRequestPayload
}
type envRequestPayload struct {
Name string
Value string
}
func newEnvRequest(raw *ssh.Request) (*envRequest, error) {
r := new(envRequest)
r.Request = raw
if err := ssh.Unmarshal(raw.Payload, &r.Payload); err != nil {
return nil, err
}
return r, nil
}
func sshString(buf io.Reader) (string, error) {
var size uint32
err := binary.Read(buf, binary.BigEndian, &size)
if err != nil {
return "", err
}
b := make([]byte, size)
err = binary.Read(buf, binary.BigEndian, b)
if err != nil {
return "", err
}
return string(b), nil
}
type execRequest struct {
*ssh.Request
Payload execRequestPayload
}
type execRequestPayload string
func newExecRequest(raw *ssh.Request) (*execRequest, error) {
r := new(execRequest)
r.Request = raw
buf := bytes.NewReader(r.Request.Payload)
var err error
var payload string
if payload, err = sshString(buf); err != nil {
return nil, err
}
r.Payload = execRequestPayload(payload)
return r, nil
}
type subsystemRequest struct {
*ssh.Request
Payload subsystemRequestPayload
}
type subsystemRequestPayload string
func newSubsystemRequest(raw *ssh.Request) (*subsystemRequest, error) {
r := new(subsystemRequest)
r.Request = raw
buf := bytes.NewReader(r.Request.Payload)
var err error
var payload string
if payload, err = sshString(buf); err != nil {
return nil, err
}
r.Payload = subsystemRequestPayload(payload)
return r, nil
}

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package ansible
import (
"errors"
"io"
"log"
"net"
"os"
"testing"
"time"
"github.com/mitchellh/packer/packer"
"golang.org/x/crypto/ssh"
)
func TestAdapter_Serve(t *testing.T) {
// done signals the adapter that the provisioner is done
done := make(chan struct{})
acceptC := make(chan struct{})
l := listener{done: make(chan struct{}), acceptC: acceptC}
config := &ssh.ServerConfig{}
ui := new(ui)
sut := newAdapter(done, &l, config, "", newUi(ui), communicator{})
go func() {
i := 0
for range acceptC {
i++
if i == 4 {
close(done)
l.Close()
}
}
}()
sut.Serve()
}
type listener struct {
done chan struct{}
acceptC chan<- struct{}
i int
}
func (l *listener) Accept() (net.Conn, error) {
log.Println("Accept() called")
l.acceptC <- struct{}{}
select {
case <-l.done:
log.Println("done, serving an error")
return nil, errors.New("listener is closed")
case <-time.After(10 * time.Millisecond):
l.i++
if l.i%2 == 0 {
c1, c2 := net.Pipe()
go func(c net.Conn) {
<-time.After(100 * time.Millisecond)
log.Println("closing c")
c.Close()
}(c1)
return c2, nil
}
}
return nil, errors.New("accept error")
}
func (l *listener) Close() error {
close(l.done)
return nil
}
func (l *listener) Addr() net.Addr {
return addr{}
}
type addr struct{}
func (a addr) Network() string {
return a.String()
}
func (a addr) String() string {
return "test"
}
type ui int
func (u *ui) Ask(s string) (string, error) {
*u++
return s, nil
}
func (u *ui) Say(s string) {
*u++
log.Println(s)
}
func (u *ui) Message(s string) {
*u++
log.Println(s)
}
func (u *ui) Error(s string) {
*u++
log.Println(s)
}
func (u *ui) Machine(s1 string, s2 ...string) {
*u++
log.Println(s1)
for _, s := range s2 {
log.Println(s)
}
}
type communicator struct{}
func (c communicator) Start(*packer.RemoteCmd) error {
return errors.New("communicator not supported")
}
func (c communicator) Upload(string, io.Reader, *os.FileInfo) error {
return errors.New("communicator not supported")
}
func (c communicator) UploadDir(dst string, src string, exclude []string) error {
return errors.New("communicator not supported")
}
func (c communicator) Download(string, io.Writer) error {
return errors.New("communicator not supported")
}

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package ansible
import (
"bufio"
"bytes"
"errors"
"fmt"
"io"
"io/ioutil"
"log"
"net"
"os"
"os/exec"
"path/filepath"
"strconv"
"strings"
"sync"
"golang.org/x/crypto/ssh"
"github.com/mitchellh/packer/common"
"github.com/mitchellh/packer/helper/config"
"github.com/mitchellh/packer/packer"
"github.com/mitchellh/packer/template/interpolate"
)
type Config struct {
common.PackerConfig `mapstructure:",squash"`
ctx interpolate.Context
// The command to run ansible
Command string
// Extra options to pass to the ansible command
ExtraArguments []string `mapstructure:"extra_arguments"`
// The main playbook file to execute.
PlaybookFile string `mapstructure:"playbook_file"`
LocalPort string `mapstructure:"local_port"`
SSHHostKeyFile string `mapstructure:"ssh_host_key_file"`
SSHAuthorizedKeyFile string `mapstructure:"ssh_authorized_key_file"`
SFTPCmd string `mapstructure:"sftp_command"`
inventoryFile string
}
type Provisioner struct {
config Config
adapter *adapter
done chan struct{}
}
func (p *Provisioner) Prepare(raws ...interface{}) error {
p.done = make(chan struct{})
err := config.Decode(&p.config, &config.DecodeOpts{
Interpolate: true,
InterpolateContext: &p.config.ctx,
InterpolateFilter: &interpolate.RenderFilter{
Exclude: []string{},
},
}, raws...)
if err != nil {
return err
}
// Defaults
if p.config.Command == "" {
p.config.Command = "ansible-playbook"
}
var errs *packer.MultiError
err = validateFileConfig(p.config.PlaybookFile, "playbook_file", true)
if err != nil {
errs = packer.MultiErrorAppend(errs, err)
}
err = validateFileConfig(p.config.SSHAuthorizedKeyFile, "ssh_authorized_key_file", true)
if err != nil {
errs = packer.MultiErrorAppend(errs, err)
}
// Check that the host key file exists, if configured
if len(p.config.SSHHostKeyFile) > 0 {
err = validateFileConfig(p.config.SSHHostKeyFile, "ssh_host_key_file", true)
if err != nil {
log.Println(p.config.SSHHostKeyFile, "does not exist")
errs = packer.MultiErrorAppend(errs, err)
}
}
if len(p.config.LocalPort) > 0 {
if _, err := strconv.ParseUint(p.config.LocalPort, 10, 16); err != nil {
errs = packer.MultiErrorAppend(errs, fmt.Errorf("local_port: %s must be a valid port", p.config.LocalPort))
}
}
if errs != nil && len(errs.Errors) > 0 {
return errs
}
return nil
}
func (p *Provisioner) Provision(ui packer.Ui, comm packer.Communicator) error {
ui.Say("Provisioning with Ansible...")
pubKeyBytes, err := ioutil.ReadFile(p.config.SSHAuthorizedKeyFile)
if err != nil {
return errors.New("Failed to load authorized key file")
}
public, _, _, _, err := ssh.ParseAuthorizedKey(pubKeyBytes)
if err != nil {
return errors.New("Failed to parse authorized key")
}
keyChecker := ssh.CertChecker{
UserKeyFallback: func(conn ssh.ConnMetadata, pubKey ssh.PublicKey) (*ssh.Permissions, error) {
if user := conn.User(); user != "packer-ansible" {
ui.Say(fmt.Sprintf("%s is not a valid user", user))
return nil, errors.New("authentication failed")
}
if !bytes.Equal(public.Marshal(), pubKey.Marshal()) {
ui.Say("unauthorized key")
return nil, errors.New("authentication failed")
}
return nil, nil
},
}
config := &ssh.ServerConfig{
AuthLogCallback: func(conn ssh.ConnMetadata, method string, err error) {
ui.Say(fmt.Sprintf("authentication attempt from %s to %s as %s using %s", conn.RemoteAddr(), conn.LocalAddr(), conn.User(), method))
},
PublicKeyCallback: keyChecker.Authenticate,
//NoClientAuth: true,
}
privateBytes, err := ioutil.ReadFile(p.config.SSHHostKeyFile)
if err != nil {
return errors.New("Failed to load private host key")
}
private, err := ssh.ParsePrivateKey(privateBytes)
if err != nil {
return errors.New("Failed to parse private host key")
}
config.AddHostKey(private)
localListener, err := func() (net.Listener, error) {
port, _ := strconv.ParseUint(p.config.LocalPort, 10, 16)
if port == 0 {
port = 2200
}
for i := 0; i < 10; i++ {
port++
l, err := net.Listen("tcp", fmt.Sprintf("127.0.0.1:%d", port))
if err == nil {
p.config.LocalPort = strconv.FormatUint(port, 10)
return l, nil
}
ui.Say(err.Error())
}
return nil, errors.New("Error setting up SSH proxy connection")
}()
if err != nil {
return err
}
ui = newUi(ui)
p.adapter = newAdapter(p.done, localListener, config, p.config.SFTPCmd, ui, comm)
defer func() {
ui.Say("shutting down the SSH proxy")
close(p.done)
p.adapter.Shutdown()
}()
go p.adapter.Serve()
if len(p.config.inventoryFile) == 0 {
tf, err := ioutil.TempFile("", "packer-provisioner-ansible")
if err != nil {
return fmt.Errorf("Error preparing inventory file: %s", err)
}
defer os.Remove(tf.Name())
inv := fmt.Sprintf("default ansible_ssh_host=127.0.0.1 ansible_ssh_user=packer-ansible ansible_ssh_port=%s", p.config.LocalPort)
_, err = tf.Write([]byte(inv))
if err != nil {
tf.Close()
return fmt.Errorf("Error preparing inventory file: %s", err)
}
tf.Close()
p.config.inventoryFile = tf.Name()
defer func() {
p.config.inventoryFile = ""
}()
}
if err := p.executeAnsible(ui); err != nil {
return fmt.Errorf("Error executing Ansible: %s", err)
}
return nil
}
func (p *Provisioner) Cancel() {
if p.done != nil {
close(p.done)
}
if p.adapter != nil {
p.adapter.Shutdown()
}
os.Exit(0)
}
func (p *Provisioner) executeAnsible(ui packer.Ui) error {
playbook, _ := filepath.Abs(p.config.PlaybookFile)
inventory := p.config.inventoryFile
args := []string{playbook, "-i", inventory}
args = append(args, p.config.ExtraArguments...)
cmd := exec.Command(p.config.Command, args...)
stdout, err := cmd.StdoutPipe()
if err != nil {
return err
}
stderr, err := cmd.StderrPipe()
if err != nil {
return err
}
wg := sync.WaitGroup{}
repeat := func(r io.ReadCloser) {
scanner := bufio.NewScanner(r)
for scanner.Scan() {
ui.Message(scanner.Text())
}
if err := scanner.Err(); err != nil {
ui.Error(err.Error())
}
wg.Done()
}
wg.Add(2)
go repeat(stdout)
go repeat(stderr)
ui.Say(fmt.Sprintf("Executing Ansible: %s", strings.Join(cmd.Args, " ")))
cmd.Start()
wg.Wait()
err = cmd.Wait()
if err != nil {
return fmt.Errorf("Non-zero exit status: %s", err)
}
return nil
}
func validateFileConfig(name string, config string, req bool) error {
if req {
if name == "" {
return fmt.Errorf("%s must be specified.", config)
}
}
info, err := os.Stat(name)
if err != nil {
return fmt.Errorf("%s: %s is invalid: %s", config, name, err)
} else if info.IsDir() {
return fmt.Errorf("%s: %s must point to a file", config, name)
}
return nil
}
// Ui provides concurrency-safe access to packer.Ui.
type Ui struct {
sem chan int
ui packer.Ui
}
func newUi(ui packer.Ui) packer.Ui {
return &Ui{sem: make(chan int, 1), ui: ui}
}
func (ui *Ui) Ask(s string) (string, error) {
ui.sem <- 1
ret, err := ui.ui.Ask(s)
<-ui.sem
return ret, err
}
func (ui *Ui) Say(s string) {
ui.sem <- 1
ui.ui.Say(s)
<-ui.sem
}
func (ui *Ui) Message(s string) {
ui.sem <- 1
ui.ui.Message(s)
<-ui.sem
}
func (ui *Ui) Error(s string) {
ui.sem <- 1
ui.ui.Error(s)
<-ui.sem
}
func (ui *Ui) Machine(t string, args ...string) {
ui.sem <- 1
ui.ui.Machine(t, args...)
<-ui.sem
}

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package ansible
import (
"crypto/rand"
"fmt"
"io"
"io/ioutil"
"os"
"testing"
"github.com/mitchellh/packer/packer"
)
func testConfig() map[string]interface{} {
m := make(map[string]interface{})
return m
}
func TestProvisioner_Impl(t *testing.T) {
var raw interface{}
raw = &Provisioner{}
if _, ok := raw.(packer.Provisioner); !ok {
t.Fatalf("must be a Provisioner")
}
}
func TestProvisionerPrepare_Defaults(t *testing.T) {
var p Provisioner
config := testConfig()
err := p.Prepare(config)
if err == nil {
t.Fatalf("should have error")
}
hostkey_file, err := ioutil.TempFile("", "hostkey")
if err != nil {
t.Fatalf("err: %s", err)
}
defer os.Remove(hostkey_file.Name())
publickey_file, err := ioutil.TempFile("", "publickey")
if err != nil {
t.Fatalf("err: %s", err)
}
defer os.Remove(publickey_file.Name())
playbook_file, err := ioutil.TempFile("", "playbook")
if err != nil {
t.Fatalf("err: %s", err)
}
defer os.Remove(playbook_file.Name())
config["ssh_host_key_file"] = hostkey_file.Name()
config["ssh_authorized_key_file"] = publickey_file.Name()
config["playbook_file"] = playbook_file.Name()
err = p.Prepare(config)
if err != nil {
t.Fatalf("err: %s", err)
}
}
func TestProvisionerPrepare_PlaybookFile(t *testing.T) {
var p Provisioner
config := testConfig()
hostkey_file, err := ioutil.TempFile("", "hostkey")
if err != nil {
t.Fatalf("err: %s", err)
}
defer os.Remove(hostkey_file.Name())
publickey_file, err := ioutil.TempFile("", "publickey")
if err != nil {
t.Fatalf("err: %s", err)
}
defer os.Remove(publickey_file.Name())
config["ssh_host_key_file"] = hostkey_file.Name()
config["ssh_authorized_key_file"] = publickey_file.Name()
err = p.Prepare(config)
if err == nil {
t.Fatal("should have error")
}
playbook_file, err := ioutil.TempFile("", "playbook")
if err != nil {
t.Fatalf("err: %s", err)
}
defer os.Remove(playbook_file.Name())
config["playbook_file"] = playbook_file.Name()
err = p.Prepare(config)
if err != nil {
t.Fatalf("err: %s", err)
}
}
func TestProvisionerPrepare_HostKeyFile(t *testing.T) {
var p Provisioner
config := testConfig()
publickey_file, err := ioutil.TempFile("", "publickey")
if err != nil {
t.Fatalf("err: %s", err)
}
defer os.Remove(publickey_file.Name())
playbook_file, err := ioutil.TempFile("", "playbook")
if err != nil {
t.Fatalf("err: %s", err)
}
defer os.Remove(playbook_file.Name())
filename := make([]byte, 10)
n, err := io.ReadFull(rand.Reader, filename)
if n != len(filename) || err != nil {
t.Fatal("could not create random file name")
}
config["ssh_host_key_file"] = fmt.Sprintf("%x", filename)
config["ssh_authorized_key_file"] = publickey_file.Name()
config["playbook_file"] = playbook_file.Name()
err = p.Prepare(config)
if err == nil {
t.Fatal("should error if ssh_host_key_file does not exist")
}
hostkey_file, err := ioutil.TempFile("", "hostkey")
if err != nil {
t.Fatalf("err: %s", err)
}
defer os.Remove(hostkey_file.Name())
config["ssh_host_key_file"] = hostkey_file.Name()
err = p.Prepare(config)
if err != nil {
t.Fatalf("err: %s", err)
}
}
func TestProvisionerPrepare_AuthorizedKeyFile(t *testing.T) {
var p Provisioner
config := testConfig()
hostkey_file, err := ioutil.TempFile("", "hostkey")
if err != nil {
t.Fatalf("err: %s", err)
}
defer os.Remove(hostkey_file.Name())
playbook_file, err := ioutil.TempFile("", "playbook")
if err != nil {
t.Fatalf("err: %s", err)
}
defer os.Remove(playbook_file.Name())
config["ssh_host_key_file"] = hostkey_file.Name()
config["playbook_file"] = playbook_file.Name()
err = p.Prepare(config)
if err == nil {
t.Fatal("should have error")
}
publickey_file, err := ioutil.TempFile("", "publickey")
if err != nil {
t.Fatalf("err: %s", err)
}
defer os.Remove(publickey_file.Name())
config["ssh_authorized_key_file"] = publickey_file.Name()
err = p.Prepare(config)
if err != nil {
t.Fatalf("err: %s", err)
}
}
func TestProvisionerPrepare_LocalPort(t *testing.T) {
var p Provisioner
config := testConfig()
hostkey_file, err := ioutil.TempFile("", "hostkey")
if err != nil {
t.Fatalf("err: %s", err)
}
defer os.Remove(hostkey_file.Name())
publickey_file, err := ioutil.TempFile("", "publickey")
if err != nil {
t.Fatalf("err: %s", err)
}
defer os.Remove(publickey_file.Name())
playbook_file, err := ioutil.TempFile("", "playbook")
if err != nil {
t.Fatalf("err: %s", err)
}
defer os.Remove(playbook_file.Name())
config["ssh_host_key_file"] = hostkey_file.Name()
config["ssh_authorized_key_file"] = publickey_file.Name()
config["playbook_file"] = playbook_file.Name()
config["local_port"] = "65537"
err = p.Prepare(config)
if err == nil {
t.Fatal("should have error")
}
config["local_port"] = "22222"
err = p.Prepare(config)
if err != nil {
t.Fatalf("err: %s", err)
}
}

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@ -78,11 +78,6 @@ func (p *Provisioner) Prepare(raws ...interface{}) error {
err := config.Decode(&p.config, &config.DecodeOpts{
Interpolate: true,
InterpolateContext: &p.config.ctx,
InterpolateFilter: &interpolate.RenderFilter{
Exclude: []string{
"execute_command",
},
},
}, raws...)
if err != nil {
return err

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@ -0,0 +1,66 @@
---
layout: "docs"
page_title: "Ansible Provisioner"
description: |-
The `ansible` Packer provisioner allows Ansible playbooks to be run to provision the machine.
---
# Ansible Provisioner
Type: `ansible`
The `ansible` Packer provisioner allows Ansible playbooks to be run to provision the machine.
## Basic Example
This is a fully functional template that will provision an image on
DigitalOcean. Replace the mock `api_token` value with your own.
```json
{
"provisioners": [
{
"type": "ansible",
"playbook_file": "./playbook.yml",
"extra_arguments": ["--private-key", "./id_packer-ansible", "-v", "-c", "paramiko"],
"ssh_authorized_key_file": "./id_packer-ansible.pub",
"ssh_host_key_file": "./packer_host_private_key"
}
],
"builders": [
{
"type": "digitalocean",
"api_token": "6a561151587389c7cf8faa2d83e94150a4202da0e2bad34dd2bf236018ffaeeb",
"image": "ubuntu-14-04-x64",
"region": "sfo1"
},
]
}
```
## Configuration Reference
Required Parameters:
- `playbook_file` - The playbook file to be run by Ansible.
- `ssh_host_key_file` - The SSH key that will be used to run the SSH server to which Ansible connects.
- `ssh_authorized_key_file` - The SSH public key of the Ansible `ssh_user`.
Optional Parameters:
- `local_port` (string) - The port on which to
attempt to listen for SSH connections. This value is a starting point.
The provisioner will attempt listen for SSH connections on the first
available of ten ports, starting at `local_port`. The default value is 2200.
- `sftp_command` (string) - The command to run on the machine to handle the
SFTP protocol that Ansible will use to transfer files. The command should
read and write on stdin and stdout, respectively. Defaults to
`/usr/lib/sftp-server -e`.
## Limitations
The `ansible` provisioner does not support SCP to transfer files.