diff --git a/cloudconfig/containerinit/container_userdata.go b/cloudconfig/containerinit/container_userdata.go
index b05e50f..905701f 100644
--- a/cloudconfig/containerinit/container_userdata.go
+++ b/cloudconfig/containerinit/container_userdata.go
@@ -65,8 +65,7 @@ var networkInterfacesFile = "/etc/network/interfaces"
 // Interfaces field.
 func GenerateNetworkConfig(networkConfig *container.NetworkConfig) (string, error) {
 	if networkConfig == nil || len(networkConfig.Interfaces) == 0 {
-		logger.Tracef("no network config to generate")
-		return "", nil
+		return "", errors.Errorf("missing container network config")
 	}
 	logger.Debugf("generating network config from %#v", *networkConfig)
 
@@ -100,6 +99,9 @@ func GenerateNetworkConfig(networkConfig *container.NetworkConfig) (string, erro
 		if !hasAddress {
 			output.WriteString("iface " + name + " inet manual\n")
 			continue
+		} else if address == string(network.ConfigDHCP) {
+			output.WriteString("iface " + name + " inet dhcp\n")
+			continue
 		}
 
 		output.WriteString("iface " + name + " inet static\n")
@@ -148,6 +150,8 @@ func PrepareNetworkConfigFromInterfaces(interfaces []network.InterfaceInfo) *Pre
 
 		if cidr := info.CIDRAddress(); cidr != "" {
 			nameToAddress[info.InterfaceName] = cidr
+		} else if info.ConfigType == network.ConfigDHCP {
+			nameToAddress[info.InterfaceName] = string(network.ConfigDHCP)
 		}
 
 		for _, dns := range info.DNSServers {
@@ -181,13 +185,13 @@ func PrepareNetworkConfigFromInterfaces(interfaces []network.InterfaceInfo) *Pre
 // might include per-interface networking config if both networkConfig
 // is not nil and its Interfaces field is not empty.
 func newCloudInitConfigWithNetworks(series string, networkConfig *container.NetworkConfig) (cloudinit.CloudConfig, error) {
-	cloudConfig, err := cloudinit.New(series)
+	config, err := GenerateNetworkConfig(networkConfig)
 	if err != nil {
 		return nil, errors.Trace(err)
 	}
-	config, err := GenerateNetworkConfig(networkConfig)
-	if err != nil || len(config) == 0 {
-		return cloudConfig, errors.Trace(err)
+	cloudConfig, err := cloudinit.New(series)
+	if err != nil {
+		return nil, errors.Trace(err)
 	}
 
 	cloudConfig.AddBootTextFile(networkInterfacesFile, config, 0644)
diff --git a/cloudconfig/containerinit/container_userdata_test.go b/cloudconfig/containerinit/container_userdata_test.go
index 1949c64..04d3af9 100644
--- a/cloudconfig/containerinit/container_userdata_test.go
+++ b/cloudconfig/containerinit/container_userdata_test.go
@@ -66,9 +66,17 @@ func (s *UserDataSuite) SetUpTest(c *gc.C) {
 		InterfaceName: "eth2",
 		ConfigType:    network.ConfigDHCP,
 		NoAutoStart:   true,
+	}, {
+		InterfaceName: "eth3",
+		ConfigType:    network.ConfigDHCP,
+		NoAutoStart:   false,
+	}, {
+		InterfaceName: "eth4",
+		ConfigType:    network.ConfigManual,
+		NoAutoStart:   true,
 	}}
 	s.expectedNetConfig = `
-auto eth0 eth1 lo
+auto eth0 eth1 eth3 lo
 
 iface lo inet loopback
   dns-nameservers ns1.invalid ns2.invalid
@@ -81,20 +89,23 @@ iface eth0 inet static
 iface eth1 inet static
   address 0.1.2.4/24
 
-iface eth2 inet manual
+iface eth2 inet dhcp
+
+iface eth3 inet dhcp
+
+iface eth4 inet manual
 `
 	s.PatchValue(containerinit.NetworkInterfacesFile, s.networkInterfacesFile)
 }
 
 func (s *UserDataSuite) TestGenerateNetworkConfig(c *gc.C) {
-	// No config or no interfaces - no error, but also noting to generate.
 	data, err := containerinit.GenerateNetworkConfig(nil)
-	c.Assert(err, jc.ErrorIsNil)
-	c.Assert(data, gc.HasLen, 0)
+	c.Assert(err, gc.ErrorMatches, "missing container network config")
+	c.Assert(data, gc.Equals, "")
 	netConfig := container.BridgeNetworkConfig("foo", 0, nil)
 	data, err = containerinit.GenerateNetworkConfig(netConfig)
-	c.Assert(err, jc.ErrorIsNil)
-	c.Assert(data, gc.HasLen, 0)
+	c.Assert(err, gc.ErrorMatches, "missing container network config")
+	c.Assert(data, gc.Equals, "")
 
 	// Test with all interface types.
 	netConfig = container.BridgeNetworkConfig("foo", 0, s.fakeInterfaces)
@@ -118,7 +129,7 @@ bootcmd:
 - install -D -m 644 /dev/null '%[1]s'
 - |-
   printf '%%s\n' '
-  auto eth0 eth1 lo
+  auto eth0 eth1 eth3 lo
 
   iface lo inet loopback
     dns-nameservers ns1.invalid ns2.invalid
@@ -131,7 +142,11 @@ bootcmd:
   iface eth1 inet static
     address 0.1.2.4/24
 
-  iface eth2 inet manual
+  iface eth2 inet dhcp
+
+  iface eth3 inet dhcp
+
+  iface eth4 inet manual
   ' > '%[1]s'
 runcmd:
 - ifup -a || true
@@ -142,9 +157,8 @@ runcmd:
 func (s *UserDataSuite) TestNewCloudInitConfigWithNetworksNoConfig(c *gc.C) {
 	netConfig := container.BridgeNetworkConfig("foo", 0, nil)
 	cloudConf, err := containerinit.NewCloudInitConfigWithNetworks("quantal", netConfig)
-	c.Assert(err, jc.ErrorIsNil)
-	expected := "#cloud-config\n{}\n"
-	assertUserData(c, cloudConf, expected)
+	c.Assert(err, gc.ErrorMatches, "missing container network config")
+	c.Assert(cloudConf, gc.IsNil)
 }
 
 func (s *UserDataSuite) TestCloudInitUserData(c *gc.C) {
@@ -152,10 +166,8 @@ func (s *UserDataSuite) TestCloudInitUserData(c *gc.C) {
 	c.Assert(err, jc.ErrorIsNil)
 	networkConfig := container.BridgeNetworkConfig("foo", 0, nil)
 	data, err := containerinit.CloudInitUserData(instanceConfig, networkConfig)
-	c.Assert(err, jc.ErrorIsNil)
-	// No need to test the exact contents here, as they are already
-	// tested separately.
-	c.Assert(string(data), jc.HasPrefix, "#cloud-config\n")
+	c.Assert(err, gc.ErrorMatches, "missing container network config")
+	c.Assert(data, gc.IsNil)
 }
 
 func assertUserData(c *gc.C, cloudConf cloudinit.CloudConfig, expected string) {
diff --git a/worker/provisioner/lxc-broker.go b/worker/provisioner/lxc-broker.go
index cc7c84c..35c97ff 100644
--- a/worker/provisioner/lxc-broker.go
+++ b/worker/provisioner/lxc-broker.go
@@ -644,19 +644,26 @@ func prepareOrGetContainerInterfaceInfo(
 
 	log.Debugf("address allocation feature flag not enabled; using multi-bridge networking for container %q", machineID)
 
-	// In case we're running on MAAS 1.8+ with devices support, we'll still
-	// call PrepareContainerInterfaceInfo(), but we'll ignore a NotSupported
-	// error if we get it (which means we're not using MAAS 1.8+).
+	fallbackInfo := []network.InterfaceInfo{{
+		InterfaceName: "eth0",
+		ConfigType:    network.ConfigDHCP,
+	}}
+
 	containerTag := names.NewMachineTag(machineID)
 	preparedInfo, err := api.PrepareContainerInterfaceInfo(containerTag)
 	if err != nil && errors.IsNotSupported(err) {
-		log.Warningf("new container %q not registered as device: not running on MAAS 1.8+", machineID)
-		return nil, nil
+		log.Warningf("%v (using fallback config)", err)
 	} else if err != nil {
 		return nil, errors.Trace(err)
 	}
 	log.Tracef("PrepareContainerInterfaceInfo returned %+v", preparedInfo)
 
+	// Use the fallback network config as a last resort.
+	if len(preparedInfo) == 0 {
+		log.Infof("using fallback network config for container %q", machineID)
+		preparedInfo = fallbackInfo
+	}
+
 	dnsServersFound := false
 	for _, info := range preparedInfo {
 		if len(info.DNSServers) > 0 {