azure/net: generate_fallback_nic emits network v2 config instead of v1

The function generate_fallback_config is used by Azure by default when
not consuming IMDS configuration data. This function is also used by any
datasource which does not implement it's own network config. This simple
fallback configuration sets up dhcp on the most likely NIC. It will now
emit network v2 instead of network v1.

This is a step toward moving all components talking in v2 and allows us
to avoid costly conversions between v1 and v2 for newer distributions
which rely on netplan.

1 files changed, 6 insertions, 1 deletions

diff --git a/cloudinit/sources/DataSourceAzure.py b/cloudinit/sources/DataSourceAzure.py
index d2fad9bb..e6ed2f3b 100755
--- a/cloudinit/sources/DataSourceAzure.py
+++ b/cloudinit/sources/DataSourceAzure.py
@@ -1241,7 +1241,7 @@ def parse_network_config(imds_metadata):
                     privateIpv4 = addr4['privateIpAddress']
                     if privateIpv4:
                         if dev_config.get('dhcp4', False):
-                            # Append static address config for nic > 1
+                            # Append static address config for ip > 1
                             netPrefix = intf['ipv4']['subnet'][0].get(
                                 'prefix', '24')
                             if not dev_config.get('addresses'):
@@ -1251,6 +1251,11 @@ def parse_network_config(imds_metadata):
                                     ip=privateIpv4, prefix=netPrefix))
                         else:
                             dev_config['dhcp4'] = True
+                            # non-primary interfaces should have a higher
+                            # route-metric (cost) so default routes prefer
+                            # primary nic due to lower route-metric value
+                            dev_config['dhcp4-overrides'] = {
+                                'route-metric': (idx + 1) * 100}
                 for addr6 in intf['ipv6']['ipAddress']:
                     privateIpv6 = addr6['privateIpAddress']
                     if privateIpv6: