cloudinit.net: add network config v2 parsing and rendering

Network configuration version 2 format is implemented in a package
called netplan (nplan)[1] which allows consolidated network config
for multiple network controllers.

- Add a new netplan renderer
- Update default policy, placing eni and sysconfig first
  This requires explicit policy to enable netplan over eni
  on systems which have both (Yakkety, Zesty, UC16)
- Allow any network state (parsed from any format cloud-init supports) to
  render to v2 if system supports netplan.
- Move eni's _subnet_is_ipv6 to common code for use by other renderers
- Make sysconfig renderer always emit /etc/syconfig/network configuration
- Update cloud-init.service systemd unit to also wait on
  systemd-networkd-wait-online.service

1. https://lists.ubuntu.com/archives/ubuntu-devel/2016-July/039464.html

1 files changed, 3 insertions, 1 deletions

diff --git a/cloudinit/net/renderers.py b/cloudinit/net/renderers.py
index 5ad84553..5117b4a5 100644
--- a/cloudinit/net/renderers.py
+++ b/cloudinit/net/renderers.py
@@ -1,15 +1,17 @@
 # This file is part of cloud-init. See LICENSE file for license information.
 
 from . import eni
+from . import netplan
 from . import RendererNotFoundError
 from . import sysconfig
 
 NAME_TO_RENDERER = {
     "eni": eni,
+    "netplan": netplan,
     "sysconfig": sysconfig,
 }
 
-DEFAULT_PRIORITY = ["eni", "sysconfig"]
+DEFAULT_PRIORITY = ["eni", "sysconfig", "netplan"]
 
 
 def search(priority=None, target=None, first=False):