Update behavior of base bond interface with NetworkManager (canonical…

…#5385)

When using NetworkManager, if the base bond interface does not have
subnet information configured, ensure it is disabled with respect to
ipv4 and ipv6. Otherwise, the base bond interface defaults to 'auto'
and will try to configure itself via DHCP. This is problematic when
using a tagged VLAN interface on top of the bond as the base
interface will try to configure itself via DHCP on the untagged VLAN.

cloudinit/net/network_manager.py

@@ -145,11 +145,13 @@ def _set_ip_method(self, family, subnet_type):
             "dhcp": "auto",
         }
 
-        # Ensure we got an [ipvX] section
-        self._set_default(family, "method", "disabled")
+        # Ensure we have an [ipvX] section, default to disabled
+        method = "disabled"
+        self._set_default(family, "method", method)
 
         try:
-            method = method_map[subnet_type]
+            if subnet_type:
+                method = method_map[subnet_type]
         except KeyError:
             # What else can we do
             method = "auto"
@@ -360,6 +362,17 @@ def render_interface(self, iface, network_state, renderer):
         found_dns_search = []
 
         # Deal with Layer 3 configuration
+        if if_type == "bond" and not iface["subnets"]:
+            # If there is no L3 subnet config for a given connection,
+            # ensure it is disabled. Without this, the interface
+            # defaults to 'auto' which implies DHCP. This is problematic
+            # for certain configurations such as bonds where the root
+            # device itself may not have a subnet config and should be
+            # disabled while a separate VLAN interface on the bond holds
+            # the subnet information.
+            for family in ["ipv4", "ipv6"]:
+                self._set_ip_method(family, None)
+
         for subnet in iface["subnets"]:
             family = "ipv6" if subnet_is_ipv6(subnet) else "ipv4"
 

tests/unittests/net/test_network_manager.py

@@ -130,6 +130,14 @@ def test_bond_dns_baseline(self, tmpdir):
                 [bond]
                 mode=802.3ad
 
+                [ipv4]
+                method=disabled
+                may-fail=false
+
+                [ipv6]
+                method=disabled
+                may-fail=false
+
                 [ethernet]
                 mtu=9000
 
@@ -279,6 +287,14 @@ def test_bond_dns_redacted_with_method_disabled(self, tmpdir):
                 [bond]
                 mode=802.3ad
 
+                [ipv4]
+                method=disabled
+                may-fail=false
+
+                [ipv6]
+                method=disabled
+                may-fail=false
+
                 [ethernet]
                 mtu=9000