diff --git a/initialize/env.go b/initialize/env.go
index cae32f7..245fe05 100644
--- a/initialize/env.go
+++ b/initialize/env.go
@@ -28,6 +28,8 @@ func NewEnvironment(root, configRoot, workspace, netconfType, sshKeyName string,
 	for k, v := range map[string]string{
 		"$public_ipv4":  os.Getenv("COREOS_PUBLIC_IPV4"),
 		"$private_ipv4": os.Getenv("COREOS_PRIVATE_IPV4"),
+		"$public_ipv6":  os.Getenv("COREOS_PUBLIC_IPV6"),
+		"$private_ipv6": os.Getenv("COREOS_PRIVATE_IPV6"),
 	} {
 		if _, ok := substitutions[k]; !ok {
 			substitutions[k] = v
@@ -80,6 +82,12 @@ func (e *Environment) DefaultEnvironmentFile() *system.EnvFile {
 	if ip, ok := e.substitutions["$private_ipv4"]; ok && len(ip) > 0 {
 		ef.Vars["COREOS_PRIVATE_IPV4"] = ip
 	}
+	if ip, ok := e.substitutions["$public_ipv6"]; ok && len(ip) > 0 {
+		ef.Vars["COREOS_PUBLIC_IPV6"] = ip
+	}
+	if ip, ok := e.substitutions["$private_ipv6"]; ok && len(ip) > 0 {
+		ef.Vars["COREOS_PRIVATE_IPV6"] = ip
+	}
 	if len(ef.Vars) == 0 {
 		return nil
 	} else {
diff --git a/initialize/env_test.go b/initialize/env_test.go
index 61d929f..c45283d 100644
--- a/initialize/env_test.go
+++ b/initialize/env_test.go
@@ -12,6 +12,8 @@ import (
 func TestEnvironmentApply(t *testing.T) {
 	os.Setenv("COREOS_PUBLIC_IPV4", "1.2.3.4")
 	os.Setenv("COREOS_PRIVATE_IPV4", "5.6.7.8")
+	os.Setenv("COREOS_PUBLIC_IPV6", "1234::")
+	os.Setenv("COREOS_PRIVATE_IPV6", "5678::")
 	for _, tt := range []struct {
 		subs  map[string]string
 		input string
@@ -23,14 +25,16 @@ func TestEnvironmentApply(t *testing.T) {
 			map[string]string{
 				"$public_ipv4":  "192.0.2.3",
 				"$private_ipv4": "192.0.2.203",
+				"$public_ipv6":  "fe00:1234::",
+				"$private_ipv6": "fe00:5678::",
 			},
 			`[Service]
-ExecStart=/usr/bin/echo "$public_ipv4"
-ExecStop=/usr/bin/echo $private_ipv4
+ExecStart=/usr/bin/echo "$public_ipv4 $public_ipv6"
+ExecStop=/usr/bin/echo $private_ipv4 $private_ipv6
 ExecStop=/usr/bin/echo $unknown`,
 			`[Service]
-ExecStart=/usr/bin/echo "192.0.2.3"
-ExecStop=/usr/bin/echo 192.0.2.203
+ExecStart=/usr/bin/echo "192.0.2.3 fe00:1234::"
+ExecStop=/usr/bin/echo 192.0.2.203 fe00:5678::
 ExecStop=/usr/bin/echo $unknown`,
 		},
 		{
@@ -65,8 +69,10 @@ func TestEnvironmentFile(t *testing.T) {
 	subs := map[string]string{
 		"$public_ipv4":  "1.2.3.4",
 		"$private_ipv4": "5.6.7.8",
+		"$public_ipv6":  "1234::",
+		"$private_ipv6": "5678::",
 	}
-	expect := "COREOS_PRIVATE_IPV4=5.6.7.8\nCOREOS_PUBLIC_IPV4=1.2.3.4\n"
+	expect := "COREOS_PRIVATE_IPV4=5.6.7.8\nCOREOS_PRIVATE_IPV6=5678::\nCOREOS_PUBLIC_IPV4=1.2.3.4\nCOREOS_PUBLIC_IPV6=1234::\n"
 
 	dir, err := ioutil.TempDir(os.TempDir(), "coreos-cloudinit-")
 	if err != nil {
@@ -96,6 +102,8 @@ func TestEnvironmentFileNil(t *testing.T) {
 	subs := map[string]string{
 		"$public_ipv4":  "",
 		"$private_ipv4": "",
+		"$public_ipv6":  "",
+		"$private_ipv6": "",
 	}
 
 	env := NewEnvironment("./", "./", "./", "", "", subs)
diff --git a/initialize/meta_data.go b/initialize/meta_data.go
index 49b975c..23ef08c 100644
--- a/initialize/meta_data.go
+++ b/initialize/meta_data.go
@@ -5,8 +5,8 @@ import (
 	"sort"
 )
 
-// ParseMetaData parses a JSON blob in the OpenStack metadata service format, and
-// converts it to a partially hydrated CloudConfig
+// ParseMetaData parses a JSON blob in the OpenStack metadata service format,
+// and converts it to a partially hydrated CloudConfig.
 func ParseMetaData(contents string) (*CloudConfig, error) {
 	if len(contents) == 0 {
 		return nil, nil
@@ -34,22 +34,31 @@ func ParseMetaData(contents string) (*CloudConfig, error) {
 	return &cfg, nil
 }
 
-// ExtractIPsFromMetaData parses a JSON blob in the OpenStack metadata service format,
-// and returns a substitution map possibly containing private_ipv4 and public_ipv4 addresses
+// ExtractIPsFromMetaData parses a JSON blob in the OpenStack metadata service
+// format and returns a substitution map possibly containing private_ipv4,
+// public_ipv4, private_ipv6, and public_ipv6 addresses.
 func ExtractIPsFromMetadata(contents []byte) (map[string]string, error) {
 	var ips struct {
-		Public  string `json:"public-ipv4"`
-		Private string `json:"local-ipv4"`
+		PublicIPv4  string `json:"public-ipv4"`
+		PrivateIPv4 string `json:"local-ipv4"`
+		PublicIPv6  string `json:"public-ipv6"`
+		PrivateIPv6 string `json:"local-ipv6"`
 	}
 	if err := json.Unmarshal(contents, &ips); err != nil {
 		return nil, err
 	}
 	m := make(map[string]string)
-	if ips.Private != "" {
-		m["$private_ipv4"] = ips.Private
+	if ips.PrivateIPv4 != "" {
+		m["$private_ipv4"] = ips.PrivateIPv4
 	}
-	if ips.Public != "" {
-		m["$public_ipv4"] = ips.Public
+	if ips.PublicIPv4 != "" {
+		m["$public_ipv4"] = ips.PublicIPv4
+	}
+	if ips.PrivateIPv6 != "" {
+		m["$private_ipv6"] = ips.PrivateIPv6
+	}
+	if ips.PublicIPv6 != "" {
+		m["$public_ipv6"] = ips.PublicIPv6
 	}
 	return m, nil
 }
diff --git a/initialize/meta_data_test.go b/initialize/meta_data_test.go
index 2e03281..5b09fbf 100644
--- a/initialize/meta_data_test.go
+++ b/initialize/meta_data_test.go
@@ -43,9 +43,9 @@ func TestExtractIPsFromMetadata(t *testing.T) {
 		out map[string]string
 	}{
 		{
-			[]byte(`{"public-ipv4": "12.34.56.78", "local-ipv4": "1.2.3.4"}`),
+			[]byte(`{"public-ipv4": "12.34.56.78", "local-ipv4": "1.2.3.4", "public-ipv6": "1234::", "local-ipv6": "5678::"}`),
 			false,
-			map[string]string{"$public_ipv4": "12.34.56.78", "$private_ipv4": "1.2.3.4"},
+			map[string]string{"$public_ipv4": "12.34.56.78", "$private_ipv4": "1.2.3.4", "$public_ipv6": "1234::", "$private_ipv6": "5678::"},
 		},
 		{
 			[]byte(`{"local-ipv4": "127.0.0.1", "something_else": "don't care"}`),