Allow configurable VNC bind IP for QEMU

This commit allows for a user configurable VNC bind IP to be used for
QEMU.

By default this will be 127.0.0.1, alternatively, a user can use
0.0.0.0 which will bind to all interfaces.

This pull request should satisfy concerns of #3570 and #3559. It is
also in-line with the functionality provided by #3566 and #3565

Signed-off-by: Ian Duffy <ian@ianduffy.ie>

builder/qemu/builder.go

@@ -104,6 +104,7 @@ type Config struct {
 	ShutdownCommand string     `mapstructure:"shutdown_command"`
 	SSHHostPortMin  uint       `mapstructure:"ssh_host_port_min"`
 	SSHHostPortMax  uint       `mapstructure:"ssh_host_port_max"`
+	VNCBindAddress  string     `mapstructure:"vnc_bind_address"`
 	VNCPortMin      uint       `mapstructure:"vnc_port_min"`
 	VNCPortMax      uint       `mapstructure:"vnc_port_max"`
 	VMName          string     `mapstructure:"vm_name"`
@@ -194,6 +195,10 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 		b.config.SSHHostPortMax = 4444
 	}
 
+	if b.config.VNCBindAddress == "" {
+		b.config.VNCBindAddress = "127.0.0.1"
+	}
+
 	if b.config.VNCPortMin == 0 {
 		b.config.VNCPortMin = 5900
 	}

builder/qemu/builder_test.go

@@ -132,6 +132,25 @@ func TestBuilderPrepare_BootWait(t *testing.T) {
 	}
 }
 
+func TestBuilderPrepare_VNCBindAddress(t *testing.T) {
+	var b Builder
+	config := testConfig()
+
+	// Test a default boot_wait
+	delete(config, "vnc_bind_address")
+	warns, err := b.Prepare(config)
+	if len(warns) > 0 {
+		t.Fatalf("bad: %#v", warns)
+	}
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if b.config.VNCBindAddress != "127.0.0.1" {
+		t.Fatalf("bad value: %s", b.config.VNCBindAddress)
+	}
+}
+
 func TestBuilderPrepare_DiskCompaction(t *testing.T) {
 	var b Builder
 	config := testConfig()

builder/qemu/step_configure_vnc.go

@@ -26,7 +26,7 @@ func (stepConfigureVNC) Run(state multistep.StateBag) multistep.StepAction {
 	// Find an open VNC port. Note that this can still fail later on
 	// because we have to release the port at some point. But this does its
 	// best.
-	msg := fmt.Sprintf("Looking for available port between %d and %d", config.VNCPortMin, config.VNCPortMax)
+	msg := fmt.Sprintf("Looking for available port between %d and %d on %s", config.VNCPortMin, config.VNCPortMax, config.VNCBindAddress)
 	ui.Say(msg)
 	log.Printf(msg)
 	var vncPort uint
@@ -39,15 +39,16 @@ func (stepConfigureVNC) Run(state multistep.StateBag) multistep.StepAction {
 		}
 
 		log.Printf("Trying port: %d", vncPort)
-		l, err := net.Listen("tcp", fmt.Sprintf(":%d", vncPort))
+		l, err := net.Listen("tcp", fmt.Sprintf("%s:%d", config.VNCBindAddress, vncPort))
 		if err == nil {
 			defer l.Close()
 			break
 		}
 	}
 
-	ui.Say(fmt.Sprintf("Found available VNC port: %d", vncPort))
+	log.Printf("Found available VNC port: %d on IP: %s", vncPort, config.VNCBindAddress)
 	state.Put("vnc_port", vncPort)
+	state.Put("vnc_ip", config.VNCBindAddress)
 
 	return multistep.ActionContinue
 }

builder/qemu/step_run.go

@@ -61,12 +61,13 @@ func (s *stepRun) Cleanup(state multistep.StateBag) {
 func getCommandArgs(bootDrive string, state multistep.StateBag) ([]string, error) {
 	config := state.Get("config").(*Config)
 	isoPath := state.Get("iso_path").(string)
+	vncIP := state.Get("vnc_ip").(string)
 	vncPort := state.Get("vnc_port").(uint)
 	sshHostPort := state.Get("sshHostPort").(uint)
 	ui := state.Get("ui").(packer.Ui)
 	driver := state.Get("driver").(Driver)
 
-	vnc := fmt.Sprintf("0.0.0.0:%d", vncPort-5900)
+	vnc := fmt.Sprintf("%s:%d", vncIP, vncPort-5900)
 	vmName := config.VMName
 	imgPath := filepath.Join(config.OutputDir, vmName)
 
@@ -100,9 +101,22 @@ func getCommandArgs(bootDrive string, state multistep.StateBag) ([]string, error
 	deviceArgs = append(deviceArgs, fmt.Sprintf("%s,netdev=user.0", config.NetDevice))
 
 	if config.Headless == true {
-		ui.Message("WARNING: The VM will be started in headless mode, as configured.\n" +
+		vncIpRaw, vncIpOk := state.GetOk("vnc_ip")
-			"In headless mode, errors during the boot sequence or OS setup\n" +
+		vncPortRaw, vncPortOk := state.GetOk("vnc_port")
-			"won't be easily visible. Use at your own discretion.")
+
+		if vncIpOk && vncPortOk {
+			vncIp := vncIpRaw.(string)
+			vncPort := vncPortRaw.(uint)
+
+			ui.Message(fmt.Sprintf(
+				"The VM will be run headless, without a GUI. If you want to\n"+
+					"view the screen of the VM, connect via VNC without a password to\n"+
+					"%s:%d", vncIp, vncPort))
+		} else {
+			ui.Message("The VM will be run headless, without a GUI, as configured.\n" +
+				"If the run isn't succeeding as you expect, please enable the GUI\n" +
+				"to inspect the progress of the build.")
+		}
 	} else {
 		if qemuMajor >= 2 {
 			defaultArgs["-display"] = "sdl"

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

@@ -306,6 +306,10 @@ default port of `5985` or whatever value you have the service set to listen on.
     `BUILDNAME` is the name of the build. Currently, no file extension will be
     used unless it is specified in this option.
 
+-   `vnc_bind_address` (string / IP address) - The IP address that should be binded
+    to for VNC. By default packer will use 127.0.0.1 for this. If you wish to bind
+    to all interfaces use 0.0.0.0
+
 -   `vnc_port_min` and `vnc_port_max` (integer) - The minimum and maximum port
     to use for VNC access to the virtual machine. The builder uses VNC to type
     the initial `boot_command`. Because Packer generally runs in parallel,