cloudinit.net: add network config v2 parsing and rendering

Network configuration version 2 format is implemented in a package
called netplan (nplan)[1] which allows consolidated network config
for multiple network controllers.

- Add a new netplan renderer
- Update default policy, placing eni and sysconfig first
  This requires explicit policy to enable netplan over eni
  on systems which have both (Yakkety, Zesty, UC16)
- Allow any network state (parsed from any format cloud-init supports) to
  render to v2 if system supports netplan.
- Move eni's _subnet_is_ipv6 to common code for use by other renderers
- Make sysconfig renderer always emit /etc/syconfig/network configuration
- Update cloud-init.service systemd unit to also wait on
  systemd-networkd-wait-online.service

1. https://lists.ubuntu.com/archives/ubuntu-devel/2016-July/039464.html

2 files changed, 648 insertions, 4 deletions

diff --git a/tests/unittests/test_distros/test_netconfig.py b/tests/unittests/test_distros/test_netconfig.py
index bde3bb50..b89b74ff 100644
--- a/tests/unittests/test_distros/test_netconfig.py
+++ b/tests/unittests/test_distros/test_netconfig.py
@@ -17,6 +17,7 @@ from ..helpers import TestCase
 from cloudinit import distros
 from cloudinit.distros.parsers.sys_conf import SysConf
 from cloudinit import helpers
+from cloudinit.net import eni
 from cloudinit import settings
 from cloudinit import util
 
@@ -28,10 +29,10 @@ iface lo inet loopback
 auto eth0
 iface eth0 inet static
     address 192.168.1.5
-    netmask 255.255.255.0
-    network 192.168.0.0
     broadcast 192.168.1.0
     gateway 192.168.1.254
+    netmask 255.255.255.0
+    network 192.168.0.0
 
 auto eth1
 iface eth1 inet dhcp
@@ -67,6 +68,100 @@ iface eth1 inet6 static
     gateway 2607:f0d0:1002:0011::1
 '''
 
+V1_NET_CFG = {'config': [{'name': 'eth0',
+
+                          'subnets': [{'address': '192.168.1.5',
+                                       'broadcast': '192.168.1.0',
+                                       'gateway': '192.168.1.254',
+                                       'netmask': '255.255.255.0',
+                                       'type': 'static'}],
+                          'type': 'physical'},
+                         {'name': 'eth1',
+                          'subnets': [{'control': 'auto', 'type': 'dhcp4'}],
+                          'type': 'physical'}],
+              'version': 1}
+
+V1_NET_CFG_OUTPUT = """
+# This file is generated from information provided by
+# the datasource.  Changes to it will not persist across an instance.
+# To disable cloud-init's network configuration capabilities, write a file
+# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
+# network: {config: disabled}
+auto lo
+iface lo inet loopback
+
+auto eth0
+iface eth0 inet static
+    address 192.168.1.5
+    broadcast 192.168.1.0
+    gateway 192.168.1.254
+    netmask 255.255.255.0
+
+auto eth1
+iface eth1 inet dhcp
+"""
+
+V1_NET_CFG_IPV6 = {'config': [{'name': 'eth0',
+                               'subnets': [{'address':
+                                            '2607:f0d0:1002:0011::2',
+                                            'gateway':
+                                            '2607:f0d0:1002:0011::1',
+                                            'netmask': '64',
+                                            'type': 'static'}],
+                               'type': 'physical'},
+                              {'name': 'eth1',
+                               'subnets': [{'control': 'auto',
+                                            'type': 'dhcp4'}],
+                               'type': 'physical'}],
+                   'version': 1}
+
+
+V1_TO_V2_NET_CFG_OUTPUT = """
+# This file is generated from information provided by
+# the datasource.  Changes to it will not persist across an instance.
+# To disable cloud-init's network configuration capabilities, write a file
+# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
+# network: {config: disabled}
+network:
+    version: 2
+    ethernets:
+        eth0:
+            addresses:
+            - 192.168.1.5/255.255.255.0
+            gateway4: 192.168.1.254
+        eth1:
+            dhcp4: true
+"""
+
+V2_NET_CFG = {
+    'ethernets': {
+        'eth7': {
+            'addresses': ['192.168.1.5/255.255.255.0'],
+            'gateway4': '192.168.1.254'},
+        'eth9': {
+            'dhcp4': True}
+    },
+    'version': 2
+}
+
+
+V2_TO_V2_NET_CFG_OUTPUT = """
+# This file is generated from information provided by
+# the datasource.  Changes to it will not persist across an instance.
+# To disable cloud-init's network configuration capabilities, write a file
+# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
+# network: {config: disabled}
+network:
+    version: 2
+    ethernets:
+        eth7:
+            addresses:
+            - 192.168.1.5/255.255.255.0
+            gateway4: 192.168.1.254
+        eth9:
+            dhcp4: true
+"""
+
 
 class WriteBuffer(object):
     def __init__(self):
@@ -83,12 +178,14 @@ class WriteBuffer(object):
 
 class TestNetCfgDistro(TestCase):
 
-    def _get_distro(self, dname):
+    def _get_distro(self, dname, renderers=None):
         cls = distros.fetch(dname)
         cfg = settings.CFG_BUILTIN
         cfg['system_info']['distro'] = dname
+        if renderers:
+            cfg['system_info']['network'] = {'renderers': renderers}
         paths = helpers.Paths({})
-        return cls(dname, cfg, paths)
+        return cls(dname, cfg.get('system_info'), paths)
 
     def test_simple_write_ub(self):
         ub_distro = self._get_distro('ubuntu')
@@ -116,6 +213,107 @@ class TestNetCfgDistro(TestCase):
             self.assertEqual(str(write_buf).strip(), BASE_NET_CFG.strip())
             self.assertEqual(write_buf.mode, 0o644)
 
+    def test_apply_network_config_eni_ub(self):
+        ub_distro = self._get_distro('ubuntu')
+        with ExitStack() as mocks:
+            write_bufs = {}
+
+            def replace_write(filename, content, mode=0o644, omode="wb"):
+                buf = WriteBuffer()
+                buf.mode = mode
+                buf.omode = omode
+                buf.write(content)
+                write_bufs[filename] = buf
+
+            # eni availability checks
+            mocks.enter_context(
+                mock.patch.object(util, 'which', return_value=True))
+            mocks.enter_context(
+                mock.patch.object(eni, 'available', return_value=True))
+            mocks.enter_context(
+                mock.patch.object(util, 'ensure_dir'))
+            mocks.enter_context(
+                mock.patch.object(util, 'write_file', replace_write))
+            mocks.enter_context(
+                mock.patch.object(os.path, 'isfile', return_value=False))
+
+            ub_distro.apply_network_config(V1_NET_CFG, False)
+
+            self.assertEqual(len(write_bufs), 2)
+            eni_name = '/etc/network/interfaces.d/50-cloud-init.cfg'
+            self.assertIn(eni_name, write_bufs)
+            write_buf = write_bufs[eni_name]
+            self.assertEqual(str(write_buf).strip(), V1_NET_CFG_OUTPUT.strip())
+            self.assertEqual(write_buf.mode, 0o644)
+
+    def test_apply_network_config_v1_to_netplan_ub(self):
+        renderers = ['netplan']
+        ub_distro = self._get_distro('ubuntu', renderers=renderers)
+        with ExitStack() as mocks:
+            write_bufs = {}
+
+            def replace_write(filename, content, mode=0o644, omode="wb"):
+                buf = WriteBuffer()
+                buf.mode = mode
+                buf.omode = omode
+                buf.write(content)
+                write_bufs[filename] = buf
+
+            mocks.enter_context(
+                mock.patch.object(util, 'which', return_value=True))
+            mocks.enter_context(
+                mock.patch.object(util, 'write_file', replace_write))
+            mocks.enter_context(
+                mock.patch.object(util, 'ensure_dir'))
+            mocks.enter_context(
+                mock.patch.object(util, 'subp', return_value=(0, 0)))
+            mocks.enter_context(
+                mock.patch.object(os.path, 'isfile', return_value=False))
+
+            ub_distro.apply_network_config(V1_NET_CFG, False)
+
+            self.assertEqual(len(write_bufs), 1)
+            netplan_name = '/etc/netplan/50-cloud-init.yaml'
+            self.assertIn(netplan_name, write_bufs)
+            write_buf = write_bufs[netplan_name]
+            self.assertEqual(str(write_buf).strip(),
+                             V1_TO_V2_NET_CFG_OUTPUT.strip())
+            self.assertEqual(write_buf.mode, 0o644)
+
+    def test_apply_network_config_v2_passthrough_ub(self):
+        renderers = ['netplan']
+        ub_distro = self._get_distro('ubuntu', renderers=renderers)
+        with ExitStack() as mocks:
+            write_bufs = {}
+
+            def replace_write(filename, content, mode=0o644, omode="wb"):
+                buf = WriteBuffer()
+                buf.mode = mode
+                buf.omode = omode
+                buf.write(content)
+                write_bufs[filename] = buf
+
+            mocks.enter_context(
+                mock.patch.object(util, 'which', return_value=True))
+            mocks.enter_context(
+                mock.patch.object(util, 'write_file', replace_write))
+            mocks.enter_context(
+                mock.patch.object(util, 'ensure_dir'))
+            mocks.enter_context(
+                mock.patch.object(util, 'subp', return_value=(0, 0)))
+            mocks.enter_context(
+                mock.patch.object(os.path, 'isfile', return_value=False))
+
+            ub_distro.apply_network_config(V2_NET_CFG, False)
+
+            self.assertEqual(len(write_bufs), 1)
+            netplan_name = '/etc/netplan/50-cloud-init.yaml'
+            self.assertIn(netplan_name, write_bufs)
+            write_buf = write_bufs[netplan_name]
+            self.assertEqual(str(write_buf).strip(),
+                             V2_TO_V2_NET_CFG_OUTPUT.strip())
+            self.assertEqual(write_buf.mode, 0o644)
+
     def assertCfgEquals(self, blob1, blob2):
         b1 = dict(SysConf(blob1.strip().splitlines()))
         b2 = dict(SysConf(blob2.strip().splitlines()))
@@ -195,6 +393,79 @@ NETWORKING=yes
             self.assertCfgEquals(expected_buf, str(write_buf))
             self.assertEqual(write_buf.mode, 0o644)
 
+    def test_apply_network_config_rh(self):
+        renderers = ['sysconfig']
+        rh_distro = self._get_distro('rhel', renderers=renderers)
+
+        write_bufs = {}
+
+        def replace_write(filename, content, mode=0o644, omode="wb"):
+            buf = WriteBuffer()
+            buf.mode = mode
+            buf.omode = omode
+            buf.write(content)
+            write_bufs[filename] = buf
+
+        with ExitStack() as mocks:
+            # sysconfig availability checks
+            mocks.enter_context(
+                mock.patch.object(util, 'which', return_value=True))
+            mocks.enter_context(
+                mock.patch.object(util, 'write_file', replace_write))
+            mocks.enter_context(
+                mock.patch.object(util, 'load_file', return_value=''))
+            mocks.enter_context(
+                mock.patch.object(os.path, 'isfile', return_value=True))
+
+            rh_distro.apply_network_config(V1_NET_CFG, False)
+
+            self.assertEqual(len(write_bufs), 5)
+
+            # eth0
+            self.assertIn('/etc/sysconfig/network-scripts/ifcfg-eth0',
+                          write_bufs)
+            write_buf = write_bufs['/etc/sysconfig/network-scripts/ifcfg-eth0']
+            expected_buf = '''
+# Created by cloud-init on instance boot automatically, do not edit.
+#
+BOOTPROTO=static
+DEVICE=eth0
+IPADDR=192.168.1.5
+NETMASK=255.255.255.0
+NM_CONTROLLED=no
+ONBOOT=yes
+TYPE=Ethernet
+USERCTL=no
+'''
+            self.assertCfgEquals(expected_buf, str(write_buf))
+            self.assertEqual(write_buf.mode, 0o644)
+
+            # eth1
+            self.assertIn('/etc/sysconfig/network-scripts/ifcfg-eth1',
+                          write_bufs)
+            write_buf = write_bufs['/etc/sysconfig/network-scripts/ifcfg-eth1']
+            expected_buf = '''
+# Created by cloud-init on instance boot automatically, do not edit.
+#
+BOOTPROTO=dhcp
+DEVICE=eth1
+NM_CONTROLLED=no
+ONBOOT=yes
+TYPE=Ethernet
+USERCTL=no
+'''
+            self.assertCfgEquals(expected_buf, str(write_buf))
+            self.assertEqual(write_buf.mode, 0o644)
+
+            self.assertIn('/etc/sysconfig/network', write_bufs)
+            write_buf = write_bufs['/etc/sysconfig/network']
+            expected_buf = '''
+# Created by cloud-init v. 0.7
+NETWORKING=yes
+'''
+            self.assertCfgEquals(expected_buf, str(write_buf))
+            self.assertEqual(write_buf.mode, 0o644)
+
     def test_write_ipv6_rhel(self):
         rh_distro = self._get_distro('rhel')
 
@@ -274,6 +545,78 @@ IPV6_AUTOCONF=no
             self.assertCfgEquals(expected_buf, str(write_buf))
             self.assertEqual(write_buf.mode, 0o644)
 
+    def test_apply_network_config_ipv6_rh(self):
+        renderers = ['sysconfig']
+        rh_distro = self._get_distro('rhel', renderers=renderers)
+
+        write_bufs = {}
+
+        def replace_write(filename, content, mode=0o644, omode="wb"):
+            buf = WriteBuffer()
+            buf.mode = mode
+            buf.omode = omode
+            buf.write(content)
+            write_bufs[filename] = buf
+
+        with ExitStack() as mocks:
+            mocks.enter_context(
+                mock.patch.object(util, 'which', return_value=True))
+            mocks.enter_context(
+                mock.patch.object(util, 'write_file', replace_write))
+            mocks.enter_context(
+                mock.patch.object(util, 'load_file', return_value=''))
+            mocks.enter_context(
+                mock.patch.object(os.path, 'isfile', return_value=True))
+
+            rh_distro.apply_network_config(V1_NET_CFG_IPV6, False)
+
+            self.assertEqual(len(write_bufs), 5)
+
+            self.assertIn('/etc/sysconfig/network-scripts/ifcfg-eth0',
+                          write_bufs)
+            write_buf = write_bufs['/etc/sysconfig/network-scripts/ifcfg-eth0']
+            expected_buf = '''
+# Created by cloud-init on instance boot automatically, do not edit.
+#
+BOOTPROTO=static
+DEVICE=eth0
+IPV6ADDR=2607:f0d0:1002:0011::2
+IPV6INIT=yes
+NETMASK=64
+NM_CONTROLLED=no
+ONBOOT=yes
+TYPE=Ethernet
+USERCTL=no
+'''
+            self.assertCfgEquals(expected_buf, str(write_buf))
+            self.assertEqual(write_buf.mode, 0o644)
+            self.assertIn('/etc/sysconfig/network-scripts/ifcfg-eth1',
+                          write_bufs)
+            write_buf = write_bufs['/etc/sysconfig/network-scripts/ifcfg-eth1']
+            expected_buf = '''
+# Created by cloud-init on instance boot automatically, do not edit.
+#
+BOOTPROTO=dhcp
+DEVICE=eth1
+NM_CONTROLLED=no
+ONBOOT=yes
+TYPE=Ethernet
+USERCTL=no
+'''
+            self.assertCfgEquals(expected_buf, str(write_buf))
+            self.assertEqual(write_buf.mode, 0o644)
+
+            self.assertIn('/etc/sysconfig/network', write_bufs)
+            write_buf = write_bufs['/etc/sysconfig/network']
+            expected_buf = '''
+# Created by cloud-init v. 0.7
+NETWORKING=yes
+NETWORKING_IPV6=yes
+IPV6_AUTOCONF=no
+'''
+            self.assertCfgEquals(expected_buf, str(write_buf))
+            self.assertEqual(write_buf.mode, 0o644)
+
     def test_simple_write_freebsd(self):
         fbsd_distro = self._get_distro('freebsd')
 
diff --git a/tests/unittests/test_net.py b/tests/unittests/test_net.py
index 902204a0..4f07d804 100644
--- a/tests/unittests/test_net.py
+++ b/tests/unittests/test_net.py
@@ -3,6 +3,7 @@
 from cloudinit import net
 from cloudinit.net import cmdline
 from cloudinit.net import eni
+from cloudinit.net import netplan
 from cloudinit.net import network_state
 from cloudinit.net import renderers
 from cloudinit.net import sysconfig
@@ -408,6 +409,41 @@ NETWORK_CONFIGS = {
                 post-up route add default gw 65.61.151.37 || true
                 pre-down route del default gw 65.61.151.37 || true
         """).rstrip(' '),
+        'expected_netplan': textwrap.dedent("""
+            network:
+                version: 2
+                ethernets:
+                    eth1:
+                        match:
+                            macaddress: cf:d6:af:48:e8:80
+                        nameservers:
+                            addresses:
+                            - 1.2.3.4
+                            - 5.6.7.8
+                            search:
+                            - wark.maas
+                        set-name: eth1
+                    eth99:
+                        addresses:
+                        - 192.168.21.3/24
+                        dhcp4: true
+                        match:
+                            macaddress: c0:d6:9f:2c:e8:80
+                        nameservers:
+                            addresses:
+                            - 8.8.8.8
+                            - 8.8.4.4
+                            - 1.2.3.4
+                            - 5.6.7.8
+                            search:
+                            - barley.maas
+                            - sach.maas
+                            - wark.maas
+                        routes:
+                        -   to: 0.0.0.0/0.0.0.0
+                            via: 65.61.151.37
+                        set-name: eth99
+        """).rstrip(' '),
         'yaml': textwrap.dedent("""
             version: 1
             config:
@@ -450,6 +486,14 @@ NETWORK_CONFIGS = {
             # control-alias iface0
             iface iface0 inet6 dhcp
         """).rstrip(' '),
+        'expected_netplan': textwrap.dedent("""
+            network:
+                version: 2
+                ethernets:
+                    iface0:
+                        dhcp4: true
+                        dhcp6: true
+        """).rstrip(' '),
         'yaml': textwrap.dedent("""\
             version: 1
             config:
@@ -524,6 +568,126 @@ iface eth0.101 inet static
 post-up route add -net 10.0.0.0 netmask 255.0.0.0 gw 11.0.0.1 metric 3 || true
 pre-down route del -net 10.0.0.0 netmask 255.0.0.0 gw 11.0.0.1 metric 3 || true
 """),
+        'expected_netplan': textwrap.dedent("""
+            network:
+                version: 2
+                ethernets:
+                    eth0:
+                        match:
+                            macaddress: c0:d6:9f:2c:e8:80
+                        nameservers:
+                            addresses:
+                            - 8.8.8.8
+                            - 4.4.4.4
+                            - 8.8.4.4
+                            search:
+                            - barley.maas
+                            - wark.maas
+                            - foobar.maas
+                        set-name: eth0
+                    eth1:
+                        match:
+                            macaddress: aa:d6:9f:2c:e8:80
+                        nameservers:
+                            addresses:
+                            - 8.8.8.8
+                            - 4.4.4.4
+                            - 8.8.4.4
+                            search:
+                            - barley.maas
+                            - wark.maas
+                            - foobar.maas
+                        set-name: eth1
+                    eth2:
+                        match:
+                            macaddress: c0:bb:9f:2c:e8:80
+                        nameservers:
+                            addresses:
+                            - 8.8.8.8
+                            - 4.4.4.4
+                            - 8.8.4.4
+                            search:
+                            - barley.maas
+                            - wark.maas
+                            - foobar.maas
+                        set-name: eth2
+                    eth3:
+                        match:
+                            macaddress: 66:bb:9f:2c:e8:80
+                        nameservers:
+                            addresses:
+                            - 8.8.8.8
+                            - 4.4.4.4
+                            - 8.8.4.4
+                            search:
+                            - barley.maas
+                            - wark.maas
+                            - foobar.maas
+                        set-name: eth3
+                    eth4:
+                        match:
+                            macaddress: 98:bb:9f:2c:e8:80
+                        nameservers:
+                            addresses:
+                            - 8.8.8.8
+                            - 4.4.4.4
+                            - 8.8.4.4
+                            search:
+                            - barley.maas
+                            - wark.maas
+                            - foobar.maas
+                        set-name: eth4
+                    eth5:
+                        dhcp4: true
+                        match:
+                            macaddress: 98:bb:9f:2c:e8:8a
+                        nameservers:
+                            addresses:
+                            - 8.8.8.8
+                            - 4.4.4.4
+                            - 8.8.4.4
+                            search:
+                            - barley.maas
+                            - wark.maas
+                            - foobar.maas
+                        set-name: eth5
+                bonds:
+                    bond0:
+                        dhcp6: true
+                        interfaces:
+                        - eth1
+                        - eth2
+                        parameters:
+                            mode: active-backup
+                bridges:
+                    br0:
+                        addresses:
+                        - 192.168.14.2/24
+                        - 2001:1::1/64
+                        interfaces:
+                        - eth3
+                        - eth4
+                vlans:
+                    bond0.200:
+                        dhcp4: true
+                        id: 200
+                        link: bond0
+                    eth0.101:
+                        addresses:
+                        - 192.168.0.2/24
+                        - 192.168.2.10/24
+                        gateway4: 192.168.0.1
+                        id: 101
+                        link: eth0
+                        nameservers:
+                            addresses:
+                            - 192.168.0.10
+                            - 10.23.23.134
+                            search:
+                            - barley.maas
+                            - sacchromyces.maas
+                            - brettanomyces.maas
+        """).rstrip(' '),
         'yaml': textwrap.dedent("""
             version: 1
             config:
@@ -808,6 +972,99 @@ iface eth0 inet dhcp
             expected, dir2dict(tmp_dir)['/etc/network/interfaces'])
 
 
+class TestNetplanNetRendering(CiTestCase):
+
+    @mock.patch("cloudinit.net.sys_dev_path")
+    @mock.patch("cloudinit.net.read_sys_net")
+    @mock.patch("cloudinit.net.get_devicelist")
+    def test_default_generation(self, mock_get_devicelist,
+                                mock_read_sys_net,
+                                mock_sys_dev_path):
+        tmp_dir = self.tmp_dir()
+        _setup_test(tmp_dir, mock_get_devicelist,
+                    mock_read_sys_net, mock_sys_dev_path)
+
+        network_cfg = net.generate_fallback_config()
+        ns = network_state.parse_net_config_data(network_cfg,
+                                                 skip_broken=False)
+
+        render_dir = os.path.join(tmp_dir, "render")
+        os.makedirs(render_dir)
+
+        render_target = 'netplan.yaml'
+        renderer = netplan.Renderer(
+            {'netplan_path': render_target, 'postcmds': False})
+        renderer.render_network_state(render_dir, ns)
+
+        self.assertTrue(os.path.exists(os.path.join(render_dir,
+                                                    render_target)))
+        with open(os.path.join(render_dir, render_target)) as fh:
+            contents = fh.read()
+            print(contents)
+
+        expected = """
+network:
+    version: 2
+    ethernets:
+        eth1000:
+            dhcp4: true
+            match:
+                macaddress: 07-1c-c6-75-a4-be
+            set-name: eth1000
+"""
+        self.assertEqual(expected.lstrip(), contents.lstrip())
+
+
+class TestNetplanPostcommands(CiTestCase):
+    mycfg = {
+        'config': [{"type": "physical", "name": "eth0",
+                    "mac_address": "c0:d6:9f:2c:e8:80",
+                    "subnets": [{"type": "dhcp"}]}],
+        'version': 1}
+
+    @mock.patch.object(netplan.Renderer, '_netplan_generate')
+    @mock.patch.object(netplan.Renderer, '_net_setup_link')
+    def test_netplan_render_calls_postcmds(self, mock_netplan_generate,
+                                           mock_net_setup_link):
+        tmp_dir = self.tmp_dir()
+        ns = network_state.parse_net_config_data(self.mycfg,
+                                                 skip_broken=False)
+
+        render_dir = os.path.join(tmp_dir, "render")
+        os.makedirs(render_dir)
+
+        render_target = 'netplan.yaml'
+        renderer = netplan.Renderer(
+            {'netplan_path': render_target, 'postcmds': True})
+        renderer.render_network_state(render_dir, ns)
+
+        mock_netplan_generate.assert_called_with(run=True)
+        mock_net_setup_link.assert_called_with(run=True)
+
+    @mock.patch.object(netplan, "get_devicelist")
+    @mock.patch('cloudinit.util.subp')
+    def test_netplan_postcmds(self, mock_subp, mock_devlist):
+        mock_devlist.side_effect = [['lo']]
+        tmp_dir = self.tmp_dir()
+        ns = network_state.parse_net_config_data(self.mycfg,
+                                                 skip_broken=False)
+
+        render_dir = os.path.join(tmp_dir, "render")
+        os.makedirs(render_dir)
+
+        render_target = 'netplan.yaml'
+        renderer = netplan.Renderer(
+            {'netplan_path': render_target, 'postcmds': True})
+        renderer.render_network_state(render_dir, ns)
+
+        expected = [
+            mock.call(['netplan', 'generate'], capture=True),
+            mock.call(['udevadm', 'test-builtin', 'net_setup_link',
+                       '/sys/class/net/lo'], capture=True),
+        ]
+        mock_subp.assert_has_calls(expected)
+
+
 class TestEniNetworkStateToEni(CiTestCase):
     mycfg = {
         'config': [{"type": "physical", "name": "eth0",
@@ -953,6 +1210,50 @@ class TestCmdlineReadKernelConfig(CiTestCase):
         self.assertEqual(found['config'], expected)
 
 
+class TestNetplanRoundTrip(CiTestCase):
+    def _render_and_read(self, network_config=None, state=None,
+                         netplan_path=None, dir=None):
+        if dir is None:
+            dir = self.tmp_dir()
+
+        if network_config:
+            ns = network_state.parse_net_config_data(network_config)
+        elif state:
+            ns = state
+        else:
+            raise ValueError("Expected data or state, got neither")
+
+        if netplan_path is None:
+            netplan_path = 'etc/netplan/50-cloud-init.yaml'
+
+        renderer = netplan.Renderer(
+            config={'netplan_path': netplan_path})
+
+        renderer.render_network_state(dir, ns)
+        return dir2dict(dir)
+
+    def testsimple_render_small_netplan(self):
+        entry = NETWORK_CONFIGS['small']
+        files = self._render_and_read(network_config=yaml.load(entry['yaml']))
+        self.assertEqual(
+            entry['expected_netplan'].splitlines(),
+            files['/etc/netplan/50-cloud-init.yaml'].splitlines())
+
+    def testsimple_render_v4_and_v6(self):
+        entry = NETWORK_CONFIGS['v4_and_v6']
+        files = self._render_and_read(network_config=yaml.load(entry['yaml']))
+        self.assertEqual(
+            entry['expected_netplan'].splitlines(),
+            files['/etc/netplan/50-cloud-init.yaml'].splitlines())
+
+    def testsimple_render_all(self):
+        entry = NETWORK_CONFIGS['all']
+        files = self._render_and_read(network_config=yaml.load(entry['yaml']))
+        self.assertEqual(
+            entry['expected_netplan'].splitlines(),
+            files['/etc/netplan/50-cloud-init.yaml'].splitlines())
+
+
 class TestEniRoundTrip(CiTestCase):
     def _render_and_read(self, network_config=None, state=None, eni_path=None,
                          links_prefix=None, netrules_path=None, dir=None):