http://pad.lv/1639030
https://bugs.launchpad.net/ubuntu/+source/cloud-init/+bug/1639030

=== Begin SRU Template ===
[Impact]
Ec2 support to of network configuration for ipv6-configured interfaces was not supported.


[Test Case]

1. launch an instance in ec2 on an ipv6 network with an allocated ipv6 address on the interface
2. allocate an ipv6 address to the network interface (as well as ipv4)
3. cat /run/cloud-init/results.json  # expect Ec2Datasource
4. sudo rm -rf /var/log/cloud-init* /var/lib/cloud; sudo reboot
5. grep 'Applying network config' /var/log/cloud-init.log # look for dhcp6
6. cat /run/cloud-init/results.json   # expect for Ec2LocalDatasource


[Regression Potential]
dhcp6 support is added above and beyond dhcp4 support. Confirm the dhcp-only instances also receive just dhcp4 config.

[Other Info]
Upstream commit at
  https://git.launchpad.net/cloud-init/commit/?id=3c45330a

=== End SRU Template ===


=== Abridged verification output  ===
ubuntu@ip-172-31-31-93:~$ dpkg-query --show cloud-init
cloud-init	0.7.9-153-g16a7302f-0ubuntu1~16.04.2
ubuntu@ip-172-31-31-93:~$ grep CODE /etc/os-release 
VERSION_CODENAME=xenial
UBUNTU_CODENAME=xenial
ubuntu@ip-172-31-31-93:~$ dpkg-query --show cloud-init
cloud-init	0.7.9-153-g16a7302f-0ubuntu1~16.04.2
ubuntu@ip-172-31-31-93:~$ cat /run/cloud-init/result.json 
{
 "v1": {
  "datasource": "DataSourceEc2",
  "errors": []
 }
}
ubuntu@ip-172-31-31-93:~$ grep Traceback /var/log/cloud-init.log 
ubuntu@ip-172-31-31-93:~$ 
ubuntu@ip-172-31-31-93:~$ sudo apt install cloud-init
....
ubuntu@ip-172-31-31-93:~$ dpkg-query --show cloud-init
cloud-init	17.1-18-gd4f70470-0ubuntu1~16.04.1
ubuntu@ip-172-31-31-93:~$ sudo rm -rf /var/log/cloud-init* /var/lib/cloud/; sudo reboot
...  # after clean run
ubuntu@ip-172-31-31-93:~$ dpkg-query --show cloud-init; cat /run/cloud-init/result.json ; grep Traceback /var/log/cloud-init.log 
cloud-init	17.1-18-gd4f70470-0ubuntu1~16.04.1
{
 "v1": {
  "datasource": "DataSourceEc2Local",
  "errors": []
 }
}

ubuntu@ip-172-31-31-93:~$ cat /etc/network/interfaces.d/50-cloud-init.cfg 
# This file is generated from information provided by
# the datasource.  Changes to it will not persist across an instance.
# To disable cloud-init's network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp

# control-alias eth0
iface eth0 inet6 dhcp



=== End Abridged verification output  ===