support and render control=manual on initramfs network devices

when reading the initramfs configurewd devices and turning them
into network config, we change to not have 'auto' control (or allow=auto).
The reason for this is that if the device was still up:
 a.) it would try to bring it up again (due to bug 1570142)
 b.) it would be brought down.

'b' is problematic if there is an iscsi or network root filesystem.

Note, that ifupdown does now support 'no-auto-down' which means
that the nic should not be brought down on 'ifdown -a'.

LP: #1568637

1 files changed, 10 insertions, 7 deletions

diff --git a/cloudinit/net/__init__.py b/cloudinit/net/__init__.py
index 7a6ec3a4..647c595b 100644
--- a/cloudinit/net/__init__.py
+++ b/cloudinit/net/__init__.py
@@ -350,7 +350,7 @@ def _klibc_to_config_entry(content, mac_addrs=None):
         # if no IPV4ADDR or IPV6ADDR, then go on.
         if pre + "ADDR" not in data:
             continue
-        subnet = {'type': proto}
+        subnet = {'type': proto, 'control': 'manual'}
 
         # these fields go right on the subnet
         for key in ('NETMASK', 'BROADCAST', 'GATEWAY'):
@@ -444,12 +444,13 @@ def iface_add_subnet(iface, subnet):
 def iface_add_attrs(iface):
     content = ""
     ignore_map = [
-        'type',
-        'name',
+        'control',
+        'index',
         'inet',
         'mode',
-        'index',
+        'name',
         'subnets',
+        'type',
     ]
     if iface['type'] not in ['bond', 'bridge', 'vlan']:
         ignore_map.append('mac_address')
@@ -540,6 +541,7 @@ def render_interfaces(network_state):
                     content += "\n"
                 iface['index'] = index
                 iface['mode'] = subnet['type']
+                iface['control'] = subnet.get('control', 'auto')
                 if iface['mode'].endswith('6'):
                     iface['inet'] += '6'
                 elif iface['mode'] == 'static' and ":" in subnet['address']:
@@ -548,11 +550,11 @@ def render_interfaces(network_state):
                     iface['mode'] = 'dhcp'
 
                 if index == 0:
-                    if subnet['type'] != 'manual':
-                        content += "auto {name}\n".format(**iface)
+                    if iface['control'] != 'manual':
+                        content += "allow-{control} {name}\n".format(**iface)
                     content += "iface {name} {inet} {mode}\n".format(**iface)
                 else:
-                    if subnet['type'] != 'manual':
+                    if iface['control'] != 'manual':
                         content += "auto {name}:{index}\n".format(**iface)
                     content += \
                         "iface {name}:{index} {inet} {mode}\n".format(**iface)
@@ -560,6 +562,7 @@ def render_interfaces(network_state):
                 content += iface_add_subnet(iface, subnet)
                 content += iface_add_attrs(iface)
         else:
+            # ifenslave docs say to auto the slave devices
             if 'bond-master' in iface:
                 content += "auto {name}\n".format(**iface)
             content += "iface {name} {inet} {mode}\n".format(**iface)