Fix eni rendering of multiple IPs per interface

The iface:alias syntax for eni rendering is brittle with ipv6.
Replace it with using multiple iface stanzas with the same iface
name which is supported.  Side-effect is that one can no longer
do 'ifup $iface:$alias' but requires instead use of ip address
{add|delete} instead.

LP: #1657940

1 files changed, 19 insertions, 14 deletions

diff --git a/cloudinit/net/eni.py b/cloudinit/net/eni.py
index b06ffac9..5b249f1f 100644
--- a/cloudinit/net/eni.py
+++ b/cloudinit/net/eni.py
@@ -90,8 +90,6 @@ def _iface_add_attrs(iface, index):
 
 def _iface_start_entry(iface, index, render_hwaddress=False):
     fullname = iface['name']
-    if index != 0:
-        fullname += ":%s" % index
 
     control = iface['control']
     if control == "auto":
@@ -113,6 +111,16 @@ def _iface_start_entry(iface, index, render_hwaddress=False):
     return lines
 
 
+def _subnet_is_ipv6(subnet):
+    # 'static6' or 'dhcp6'
+    if subnet['type'].endswith('6'):
+        # This is a request for DHCPv6.
+        return True
+    elif subnet['type'] == 'static' and ":" in subnet['address']:
+        return True
+    return False
+
+
 def _parse_deb_config_data(ifaces, contents, src_dir, src_path):
     """Parses the file contents, placing result into ifaces.
 
@@ -354,21 +362,23 @@ class Renderer(renderer.Renderer):
         sections = []
         subnets = iface.get('subnets', {})
         if subnets:
-            for index, subnet in zip(range(0, len(subnets)), subnets):
+            for index, subnet in enumerate(subnets):
                 iface['index'] = index
                 iface['mode'] = subnet['type']
                 iface['control'] = subnet.get('control', 'auto')
                 subnet_inet = 'inet'
-                if iface['mode'].endswith('6'):
-                    # This is a request for DHCPv6.
-                    subnet_inet += '6'
-                elif iface['mode'] == 'static' and ":" in subnet['address']:
-                    # This is a static IPv6 address.
+                if _subnet_is_ipv6(subnet):
                     subnet_inet += '6'
                 iface['inet'] = subnet_inet
-                if iface['mode'].startswith('dhcp'):
+                if subnet['type'].startswith('dhcp'):
                     iface['mode'] = 'dhcp'
 
+                # do not emit multiple 'auto $IFACE' lines as older (precise)
+                # ifupdown complains
+                if True in ["auto %s" % (iface['name']) in line
+                            for line in sections]:
+                    iface['control'] = 'alias'
+
                 lines = list(
                     _iface_start_entry(
                         iface, index, render_hwaddress=render_hwaddress) +
@@ -378,11 +388,6 @@ class Renderer(renderer.Renderer):
                 for route in subnet.get('routes', []):
                     lines.extend(self._render_route(route, indent="    "))
 
-                if len(subnets) > 1 and index == 0:
-                    tmpl = "    post-up ifup %s:%s\n"
-                    for i in range(1, len(subnets)):
-                        lines.append(tmpl % (iface['name'], i))
-
                 sections.append(lines)
         else:
             # ifenslave docs say to auto the slave devices