Azure: only generate config for NICs with addresses (#709)

Prevent network interfaces without IP addresses from being added to the
generated network configuration.

2 files changed, 47 insertions, 1 deletions

diff --git a/cloudinit/sources/DataSourceAzure.py b/cloudinit/sources/DataSourceAzure.py
index 04ff2131..bedf8ea0 100755
--- a/cloudinit/sources/DataSourceAzure.py
+++ b/cloudinit/sources/DataSourceAzure.py
@@ -1969,6 +1969,7 @@ def _generate_network_config_from_imds_metadata(imds_metadata) -> dict:
     netconfig = {'version': 2, 'ethernets': {}}
     network_metadata = imds_metadata['network']
     for idx, intf in enumerate(network_metadata['interface']):
+        has_ip_address = False
         # First IPv4 and/or IPv6 address will be obtained via DHCP.
         # Any additional IPs of each type will be set as static
         # addresses.
@@ -1978,6 +1979,11 @@ def _generate_network_config_from_imds_metadata(imds_metadata) -> dict:
                       'dhcp6': False}
         for addr_type in ('ipv4', 'ipv6'):
             addresses = intf.get(addr_type, {}).get('ipAddress', [])
+            # If there are no available IP addresses, then we don't
+            # want to add this interface to the generated config.
+            if not addresses:
+                continue
+            has_ip_address = True
             if addr_type == 'ipv4':
                 default_prefix = '24'
             else:
@@ -1998,7 +2004,7 @@ def _generate_network_config_from_imds_metadata(imds_metadata) -> dict:
                 dev_config['addresses'].append(
                     '{ip}/{prefix}'.format(
                         ip=privateIp, prefix=netPrefix))
-        if dev_config:
+        if dev_config and has_ip_address:
             mac = ':'.join(re.findall(r'..', intf['macAddress']))
             dev_config.update({
                 'match': {'macaddress': mac.lower()},
diff --git a/tests/unittests/test_datasource/test_azure.py b/tests/unittests/test_datasource/test_azure.py
index e363c1f9..d64b538e 100644
--- a/tests/unittests/test_datasource/test_azure.py
+++ b/tests/unittests/test_datasource/test_azure.py
@@ -159,6 +159,22 @@ SECONDARY_INTERFACE = {
     }
 }
 
+SECONDARY_INTERFACE_NO_IP = {
+    "macAddress": "220D3A047598",
+    "ipv6": {
+        "ipAddress": []
+    },
+    "ipv4": {
+        "subnet": [
+            {
+                "prefix": "24",
+                "address": "10.0.1.0"
+            }
+        ],
+        "ipAddress": []
+    }
+}
+
 IMDS_NETWORK_METADATA = {
     "interface": [
         {
@@ -1139,6 +1155,30 @@ scbus-1 on xpt0 bus 0
         dsrc.get_data()
         self.assertEqual(expected_network_config, dsrc.network_config)
 
+    @mock.patch('cloudinit.sources.DataSourceAzure.device_driver',
+                return_value=None)
+    def test_network_config_set_from_imds_for_secondary_nic_no_ip(
+            self, m_driver):
+        """If an IP address is empty then there should no config for it."""
+        sys_cfg = {'datasource': {'Azure': {'apply_network_config': True}}}
+        odata = {}
+        data = {'ovfcontent': construct_valid_ovf_env(data=odata),
+                'sys_cfg': sys_cfg}
+        expected_network_config = {
+            'ethernets': {
+                'eth0': {'set-name': 'eth0',
+                         'match': {'macaddress': '00:0d:3a:04:75:98'},
+                         'dhcp6': False,
+                         'dhcp4': True,
+                         'dhcp4-overrides': {'route-metric': 100}}},
+            'version': 2}
+        imds_data = copy.deepcopy(NETWORK_METADATA)
+        imds_data['network']['interface'].append(SECONDARY_INTERFACE_NO_IP)
+        self.m_get_metadata_from_imds.return_value = imds_data
+        dsrc = self._get_ds(data)
+        dsrc.get_data()
+        self.assertEqual(expected_network_config, dsrc.network_config)
+
     def test_availability_zone_set_from_imds(self):
         """Datasource.availability returns IMDS platformFaultDomain."""
         sys_cfg = {'datasource': {'Azure': {'apply_network_config': True}}}