I am facing a problem how to set up network correctly while using ubuntu 17.10 in virtualbox. I have problem with pinging my instances from host PC and even from guest VM. Same problem in instances, they can't ping VMs or host pc. In virtualbox I am using 3 network adapters (NAT for internet access, 2x host only network paravirtualized [one for communication between nodes another one was meant to be public interface for instances]).
/etc/network/interfaces
# The loopback network interface
auto lo
iface lo inet loopback
# VirtualBox NAT -- for Internet access to VM
auto enp0s3
iface enp0s3 inet dhcp
auto enp0s8
iface enp0s8 inet static
address 172.18.161.6
netmask 255.255.255.0
auto enp0s9
iface enp0s9 inet manual
up ip link set dev $iface up
down ip link set dev $iface down
And devstack local.conf was from this page (tried all of them): https://docs.openstack.org/devstack/latest/guides/neutron.html