cloud-init mishandles dhcp6 subnets in network_data.json

[ubuntu-server-builder]

This bug was originally filed in Launchpad as LP: #1734739

Launchpad details

affected_projects = []
assignee = None
assignee_name = None
date_closed = 2017-11-28T14:20:56.503205+00:00
date_created = 2017-11-27T18:16:52.960486+00:00
date_fix_committed = None
date_fix_released = None
id = 1734739
importance = undecided
is_complete = True
lp_url = https://bugs.launchpad.net/cloud-init/+bug/1734739
milestone = None
owner = rmccabe
owner_name = Ryan McCabe
private = False
status = invalid
submitter = rmccabe
submitter_name = Ryan McCabe
tags = []
duplicates = []

Launchpad user Ryan McCabe(rmccabe) wrote on 2017-11-27T18:16:52.960486+00:00

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.

[ubuntu-server-builder]

Launchpad user Ryan McCabe(rmccabe) wrote on 2017-11-28T14:20:35.857245+00:00

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

[ubuntu-server-builder]

Launchpad user Scott Moser(smoser) wrote on 2017-11-28T14:52:43.150796+00:00

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?