Comment 4 for bug 1779163

Hi Rick. This is a Juju openstack environment and the controller has a floating IP. Other than that, the underlay and overlay networks match per the info below:

$ juju model-config -m controller | egrep 'fan|use-'
container-networking-method model fan
fan-config model 10.200.0.0/24=252.0.0.0/8
use-default-secgroup controller true
use-floating-ip controller true
use-openstack-gbp default false

$ juju model-config -m default | egrep 'fan|use-'
container-networking-method model fan
fan-config model 10.200.0.0/24=252.0.0.0/8
use-default-secgroup controller true
use-floating-ip default false
use-openstack-gbp default false

$ juju models --debug
[...]
connecting to API addresses: [10.200.0.152:17070 10.10.0.178:17070 252.152.0.1:17070]
[...]

$ juju ssh -m controller 0 'ip -o -4 a s;fanctl show'
1: lo inet 127.0.0.1/8 scope host lo\ valid_lft forever preferred_lft forever
2: ens2 inet 10.200.0.152/24 brd 10.200.0.255 scope global dynamic ens2\ valid_lft 49097sec preferred_lft 49097sec
3: fan-252 inet 252.152.0.1/8 scope global fan-252\ valid_lft forever preferred_lft forever
Bridge Underlay Overlay Flags
fan-252 10.200.0.152/24 252.0.0.0/8 enable dhcp

$ juju ssh -m default 0 'ip -o -4 a s;fanctl show'
1: lo inet 127.0.0.1/8 scope host lo\ valid_lft forever preferred_lft forever
2: ens2 inet 10.200.0.129/24 brd 10.200.0.255 scope global dynamic ens2\ valid_lft 56736sec preferred_lft 56736sec
3: fan-252 inet 252.129.0.1/8 scope global fan-252\ valid_lft forever preferred_lft forever
5: lxdbr0 inet 10.250.154.1/24 scope global lxdbr0\ valid_lft forever preferred_lft forever
Bridge Underlay Overlay Flags
fan-252 10.200.0.129/24 252.0.0.0/8 enable dhcp

If I ssh into the controller and I ping the overlay IPs on the units in the default model (even the LXD inside a nova instance, which only has the overlay IP as main IP).