cloud-init mishandles dhcp6 subnets in network_data.json

[Ryan McCabe]

It looks like there's a typo in the helpers/openstack.py network_data.json parser.

With a config like:

{
  "links" : [ {
    "name" : "test",
    "id" : "test",
    "type" : "vif"
  } ],
  "networks" : [ {
    "netmask" : "255.255.255.0",
    "link" : "test",
    "id" : "test",
    "ip_address" : "192.168.122.201",
    "type" : "ipv4",
    "gateway" : "192.168.122.1"
  }, {
    "link" : "test",
    "id" : "test",
    "type" : "dhcp6"
  } ]
}

the resulting network state object is

Internal State
!!python/object:cloudinit.net.network_state.NetworkState
_network_state:
    dns:
        nameservers: []
        search: []
    interfaces:
        !!python/unicode 'test':
            address: null
            gateway: null
            inet: inet
            mac_address: null
            mode: manual
            mtu: null
            name: !!python/unicode 'test'
            subnets:
            - address: !!python/unicode '192.168.122.201'
                !!python/unicode 'gateway': !!python/unicode '192.168.122.1'
                ipv4: true
                !!python/unicode 'netmask': !!python/unicode '255.255.255.0'
                !!python/unicode 'type': static
            - !!python/unicode 'type': dhcp4
            type: physical
    routes: []
_version: 1

When it should be

Internal State
!!python/object:cloudinit.net.network_state.NetworkState
_network_state:
    dns:
        nameservers: []
        search: []
    interfaces:
        !!python/unicode 'test':
            address: null
            gateway: null
            inet: inet
            mac_address: null
            mode: manual
            mtu: null
            name: !!python/unicode 'test'
            subnets:
            - address: !!python/unicode '192.168.122.201'
                !!python/unicode 'gateway': !!python/unicode '192.168.122.1'
                ipv4: true
                !!python/unicode 'netmask': !!python/unicode '255.255.255.0'
                !!python/unicode 'type': static
            - !!python/unicode 'type': dhcp6
            type: physical
    routes: []
_version: 1

It looks like this is caused by an error on line 570 of helpers/openstack.py where the test used is:

t = 'dhcp6' if network['type'].startswith('ipv6') else 'dhcp4'

which will always result in 'dhcp4' since the network type is 'dhcp6'

it looks like changing the test to

t = 'dhcp6' if network['type'].endswith('6') else 'dhcp4'

fixes things.

[Ryan McCabe (rmccabe)]

ovirt will change to match openstack, so that no changes are needed.

[Scott Moser (smoser)]

Just for historic purposes,
Ryan's response here was due to my comment on his merge proposal that sayd:

I'm somewhat disappointed that this passed unit tests.

There are real-ish world examples at bug 1514082
of things like:
        {
            "id": "network0",
            "link": "tap54d10236-5d",
            "network_id": "a5d1181f-bedd-40a5-8b4a-5574b74dba61",
            "type": "ipv4_dhcp"
        },

Did openstack *change* the 'type' value for dhcp from
  ipv4_dhcp or ipv6_dhcp
to
  dhcp4 or dhcp6 ?

like you show in your bug?

[James Falcon (falcojr)]

Tracked in Github Issues as https://github.com/canonical/cloud-init/issues/3066