* Unentagled SSH communication with VM's from the Cloud API SSH private

key.
* Improved documentation.

builder/triton/builder.go

@@ -31,16 +31,11 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 		errs = multierror.Append(errs, err)
 	}
 
-	// In Triton only the root user is setup in a VM.
-	b.config.Comm.SSHUsername = "root"
-
 	errs = multierror.Append(errs, b.config.AccessConfig.Prepare(&b.config.ctx)...)
 	errs = multierror.Append(errs, b.config.SourceMachineConfig.Prepare(&b.config.ctx)...)
 	errs = multierror.Append(errs, b.config.Comm.Prepare(&b.config.ctx)...)
 	errs = multierror.Append(errs, b.config.TargetImageConfig.Prepare(&b.config.ctx)...)
 
-	b.config.Comm.SSHPrivateKey = b.config.KeyMaterial
-
 	return nil, errs.ErrorOrNil()
 }
 
@@ -61,9 +56,13 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	steps := []multistep.Step{
 		&StepCreateSourceMachine{},
 		&communicator.StepConnect{
-			Config:    &config.Comm,
-			Host:      commHost,
-			SSHConfig: sshConfig,
+			Config: &config.Comm,
+			Host:   commHost,
+			SSHConfig: sshConfig(
+				b.config.Comm.SSHAgentAuth,
+				b.config.Comm.SSHUsername,
+				b.config.Comm.SSHPrivateKey,
+				b.config.Comm.SSHPassword),
 		},
 		&common.StepProvision{},
 		&StepStopMachine{},

builder/triton/ssh.go

@@ -4,7 +4,13 @@ import (
 	"fmt"
 
 	"github.com/mitchellh/multistep"
+	packerssh "github.com/mitchellh/packer/communicator/ssh"
 	"golang.org/x/crypto/ssh"
+	"golang.org/x/crypto/ssh/agent"
+	"io/ioutil"
+	"log"
+	"net"
+	"os"
 )
 
 func commHost(state multistep.StateBag) (string, error) {
@@ -19,18 +25,64 @@ func commHost(state multistep.StateBag) (string, error) {
 	return machine, nil
 }
 
-func sshConfig(state multistep.StateBag) (*ssh.ClientConfig, error) {
-	config := state.Get("config").(Config)
+// SSHConfig returns a function that can be used for the SSH communicator
+// config for connecting to the instance created over SSH using the private key
+// or password.
+func sshConfig(useAgent bool, username, privateKeyPath, password string) func(multistep.StateBag) (*ssh.ClientConfig, error) {
+	return func(state multistep.StateBag) (*ssh.ClientConfig, error) {
 
-	signer, err := ssh.ParsePrivateKey([]byte(config.Comm.SSHPrivateKey))
-	if err != nil {
-		return nil, fmt.Errorf("Error setting up SSH config: %s", err)
-	}
+		if useAgent {
+			log.Println("Configuring SSH agent.")
 
-	return &ssh.ClientConfig{
-		User: config.Comm.SSHUsername,
-		Auth: []ssh.AuthMethod{
-			ssh.PublicKeys(signer),
-		},
-	}, nil
-}
+			authSock := os.Getenv("SSH_AUTH_SOCK")
+			if authSock == "" {
+				return nil, fmt.Errorf("SSH_AUTH_SOCK is not set")
+			}
+
+			sshAgent, err := net.Dial("unix", authSock)
+			if err != nil {
+				return nil, fmt.Errorf("Cannot connect to SSH Agent socket %q: %s", authSock, err)
+			}
+
+			return &ssh.ClientConfig{
+				User: username,
+				Auth: []ssh.AuthMethod{
+					ssh.PublicKeysCallback(agent.NewClient(sshAgent).Signers),
+				},
+			}, nil
+		}
+
+		hasKey := privateKeyPath != ""
+
+		if hasKey {
+			log.Printf("Configuring SSH private key '%s'.", privateKeyPath)
+
+			privateKeyBytes, err := ioutil.ReadFile(privateKeyPath)
+			if err != nil {
+				return nil, fmt.Errorf("Unable to read SSH private key: %s", err)
+			}
+
+			signer, err := ssh.ParsePrivateKey(privateKeyBytes)
+			if err != nil {
+				return nil, fmt.Errorf("Error setting up SSH config: %s", err)
+			}
+
+			return &ssh.ClientConfig{
+				User: username,
+				Auth: []ssh.AuthMethod{
+					ssh.PublicKeys(signer),
+				},
+			}, nil
+		} else {
+			log.Println("Configuring SSH keyboard interactive.")
+
+			return &ssh.ClientConfig{
+				User: username,
+				Auth: []ssh.AuthMethod{
+					ssh.Password(password),
+					ssh.KeyboardInteractive(
+						packerssh.PasswordKeyboardInteractive(password)),
+				}}, nil
+		}
+	}
+}

website/source/docs/builders/triton.html.md

@@ -18,12 +18,16 @@ Type: `triton`
 The `triton` Packer builder is able to create new images for use with Triton.
 These images can be used with both the [Joyent public
 cloud](https://www.joyent.com/) (which is powered by Triton) as well with
-private [Triton](https://github.com/joyent/triton) installations. This builder
-uses the Triton Cloud API to create images. The builder creates and launches a
-temporary VM based on a specified source image, runs any provisioning necessary,
-uses the Triton "VM to image" functionality to create a reusable image and
-finally destroys the temporary VM. This reusable image can then be used to
-launch new VM's.
+private [Triton](https://github.com/joyent/triton) installations.
+
+This builder uses the Triton Cloud API to create these images. Triton also
+supports the Docker API however this builder does *not*. If you want to create
+Docker images on Triton you should use the Packer Docker builder.
+
+The builder creates and launches a temporary VM based on a specified source
+image, runs any provisioning necessary, uses the Triton "VM to image"
+functionality to create a reusable image and finally destroys the temporary VM.
+This reusable image can then be used to launch new VM's.
 
 The builder does *not* manage images. Once it creates an image, it is up to you
 to use it or delete it.
@@ -47,9 +51,16 @@ builder.
     of `triton_key_id` is stored. For example `~/.ssh/id_rsa`.
 
 -   `source_machine_image` (string) - The UUID of the image to base the new
-    image on. On the Joyent public cloud this could for example be
+    image on. Triton supports multiple types of images, called 'brands' in
+    Triton / Joyent lingo, for contains and VM's. See the chapter [Containers
+    and virtual machines](https://docs.joyent.com/public-cloud/instances) in the
+    Joyent Triton documentation for detailed information. The following brands
+    are currently supported by this builder:`joyent` and`kvm`. The choice of
+    base image automatically decides the brand. On the Joyent public cloud a
+    valid `source_machine_image` could for example be
     `70e3ae72-96b6-11e6-9056-9737fd4d0764` for version 16.3.1 of the 64bit
-    SmartOS base image.
+    SmartOS base image (a 'joyent' brand image).
+
 -   `source_machine_package` (string) - The Triton package to use while building
     the image. Does not affect (and does not have to be the same) as the package
     which will be used for a VM instance running this image. On the Joyent
@@ -111,18 +122,28 @@ builder.
 
 ## Basic Example
 
-Below is a minimal example to create an image on the Joyent public cloud:
+Below is a minimal example to create an joyent-brand image on the Joyent public
+cloud:
 
 ``` {.javascript}
 "builders": [{
   "type": "triton",
   "triton_account": "triton_username",
   "triton_key_id": "6b:95:03:3d:d3:6e:52:69:01:96:1a:46:4a:8d:c1:7e",
-  "triton_key_material": "${file("~/.ssh/id_rsa")}",
+  "triton_key_material": "~/.ssh/id_rsa",
   "source_machine_name": "image-builder",
   "source_machine_package": "g3-standard-0.5-smartos",
   "source_machine_image": "70e3ae72-96b6-11e6-9056-9737fd4d0764",
+  "ssh_username": "root",
+  "ssh_private_key_file": "~/.ssh/id_rsa",
   "image_name": "my_new_image",
   "image_version": "1.0.0",
 }],
 ```
+
+In the above example the SSH key used for `triton_key_material` (connecting to
+the Cloud API) and the `ssh_private_key_file` (connecting to the VM once it has
+started) are the same. This is because Triton automatically configures the root
+users to be able to login via SSH with the same key used to create the VM via
+the Cloud API. In more advanced scenarios for example when using a
+`source_machine_image` one might use different credentials.