Description of problem:
I am following cloud init guide to provide Networking Config Version 1 (http://cloudinit.readthedocs.io/en/latest/topics/network-config-format-v1.html) format data to customize my VM network interface. It works for ethernet port bug crashed with bond configuraton, log is similiar as the following:
...
Traceback (most recent call last):
  File "./tools/net-convert.py", line 82, in <module>
    main()
  File "./tools/net-convert.py", line 78, in main
    r.render_network_state(ns, target=args.directory)
  File "/home/smoser-public/src/cloud-init/cloud-init/cloudinit/net/sysconfig.py", line 397, in render_network_state
    network_state).items():
  File "/home/smoser-public/src/cloud-init/cloud-init/cloudinit/net/sysconfig.py", line 379, in _render_sysconfig
    cls._render_bond_interfaces(network_state, iface_contents)
  File "/home/smoser-public/src/cloud-init/cloud-init/cloudinit/net/sysconfig.py", line 315, in _render_bond_interfaces
    iface_master_name = iface['bond-master']
KeyError: 'bond-master'

Someone have reported the same problem: https://bugs.launchpad.net/cloud-init/+bug/1682014, But it has been fixed in https://bugs.launchpad.net/cloud-init/+bug/1695092 (Fixed in Cloud-init 17.1)
 

Version-Release number of selected component (if applicable):
cloud-init-0.7.9-9.el7_4.1.x86_64

How reproducible:
Follow Networking Config Version 1 to customize bond interface, like the following:
  version: 1
  config:
    - type: physical
      name: eth0
      mac_address: 94:18:82:6f:3b:1c
      subnets:
        - type: static
          address: 172.20.0.30/24
    - type: physical
      name: eth1
      mac_address: 94:18:82:6f:3b:1d
      subnets:
        - type: dhcp4
    - type: physical
      name: eth2
      mac_address: 94:18:82:6f:3b:1e
      subnets:
        - type: dhcp4
    - type: physical
      name: eth3
      mac_address: 94:18:82:6f:3b:1f
      subnets:
        - type: dhcp4
    - type: bond
      name: bond0
      bond_interfaces:
        - eth1
        - eth2
      params:
        miimon: 100
        mode: 1
      subnets:
        - type: static
          address: 192.168.5.100/24
    - type: route
      destination: 0.0.0.0/0
      gateway: 172.16.1.1


Steps to Reproduce:
1. Generate cidata iso which contains meta-data, user-data, network-config, network-config should have the upper contents
2. Use kvm to bring up a redhat7.4/centos7.4 cloud image with iso attached. 
3. Check /var/log/cloud-init.log after instance up. bond configuration failed with exception

Actual results:
network config failed/terminated with exception

Expected results:
Network configuration is done for bond

Additional info:
Please integrated latest version of cloud-init(this bug should have been fixed in Cloud-init 17.1)