Docker Instance in multi_host network mode receives the wrong gateway ip address

[Daniel Kuffner]

A openstack docker setup in multi_host (FlatDHCPManager) network mode assigns the wrong gateway address to docker container instances.

Currently does the docker driver use the gateway information delivered by nova.
The gateway is always 10.0.0.1 (my private network). The IP address 10.0.0.1 is ot availbale.
I looked up the dnsmasq instances on all compute nodes which is in my case

node1: 10.0.0.3
node2: 10.0.0.5

I figured out if I set the default gateway of a docker container instance to the IP address of the dnsmasq everything works as expected. Therefor I assume that this has to be the gateway.

The correct dnsmasq IP address is delivered in the the network_info as shown in the example below (meta': {u'dhcp_server': u'10.0.0.5'}):

network_info:
{
    'bridge': u'br100',
    'subnets': [Subnet({
        'ips': [FixedIP({
            'meta': {},
            'version': 4,
            'type': u'fixed',
            'floating_ips': [],
            'address': u'10.0.0.10',
            })],
        'version': 4,
        'meta': {u'dhcp_server': u'10.0.0.5'},
        'dns': [IP({
            'meta': {},
            'version': 4,
            'type': u'dns',
            'address': u'10.129.184.2',
            })],
        'routes': [],
        'cidr': u'10.0.0.0/24',
        'gateway': IP({
            'meta': {},
            'version': 4,
            'type': u'gateway',
            'address': u'10.0.0.1',
            }),
        }),

[Joe Gordon (jogo)]

trunk nova doesn't have the docker driver.