On Ubuntu 18.04 host, install virtualbox 5.2.x

Open Virtualbox. Click File --> Host Network Manager --> Create . You should see vboxnet0. Check Enable DHCP Server

Enable NAT and forwarding for the newly created network and interface

echo 1 > /proc/sys/net/ipv4/ip_forward
iptables --table nat --append POSTROUTING --out-interface enp2s0 -j MASQUERADE
iptables --append FORWARD --in-interface vboxnet0 -j ACCEPT

Create a virtualbox vm with 6 cpu cores, 8 GB memory and 100GB disk

Under Network Settings of the vm, change from NAT to Host-only Adapter. It should select vboxne0 by default. Click Advanced and Select Allow All in Promiscuous Mode

Power on the vm, run 'yum update -y" and reboot

Edit /etc/sysconfig/network-scripts/ifcfg-enp0s3 and change DHCP to manual IP . The entry should look like

BOOTPROTO='none'
IPADDR='192.168.56.12'
NETMASK='255.255.255.0'
GATEWAY='192.168.56.1'
DNS1='10.58.8.50'

systemctl restart network

yum install wget net-tools telnet vim -y

yum install -y centos-release-openstack-queens

yum update -y

yum install -y openstack-packstack

systemctl stop firewalld

systemctl disable firewalld

systemctl stop NetworkManager

systemctl disable NetworkManager

setenforce 0 / Edit /etc/selinux/config and disable it permanently

packstack --gen-answer-file=/root/answer.txt

Edit the following sections in answer.txt

CONFIG_PROVISION_DEMO=n
CONFIG_KEYSTONE_ADMIN_PW=openstack

Run the installer: packstack --answer-file /root/answer.txt

After successful install under /etc/sysconfig/network-scripts create the following two files

ifcfg-br-ex:

DEVICE=br-ex
DEVICETYPE=ovs
TYPE=OVSBridge
BOOTPROTO=static
DNS1=10.58.8.50
ONBOOT=yes
IPADDR=192.168.56.12
PREFIX=24
GATEWAY=192.168.56.1

ifcfg-enp0s3:

DEVICE=enp0s3
TYPE=OVSPort
DEVICETYPE=ovs
OVS_BRIDGE=br-ex
ONBOOT=yes

systemctl restart network

Enable Promiscuous mode on host interface : ip link set enp0s3 promisc on

source keystone_admin

Cluster status: nova service-list

Create networks and a router

# Create a public/external network
neutron net-create public --provider:network_type flat --provider:physical_network extnet --router:external

neutron subnet-create public --name public_subnet --allocation-pool start=192.168.56.100,end=192.168.56.200 --disable-dhcp --gateway 192.168.56.1 192.168.56.0/24

# Create router
neutron router-create router1 --ha False

# Set interfaces
neutron router-gateway-set router1 public

neutron router-interface-add router1 private_subnet

Check router port status

neutron router-list --fields name --fields id

neutron router-port-list id

neutron port-show id

If you need to restart the router

neutron port-update routerid --admin-state-up False
neutron port-update routerid --admin-state-up True

Login to dashboard at http://192.168.56.12/dashboard using admin/openstack nd create virtual machines

If you see No valid host found error, run: systemctl restart openstack-nova-compute.service and create the instance again

Troubleshooting neutron

grep -E -i "error|trace" /var/log/neutron/server.log
cat /etc/neutron/plugins/ml2/openvswitch_agent.ini and make sure bridge mapping     looks exactly like 'bridge_mappings=extnet:br-ex

If your virtualbox runs on MacOS add the following in /etc/pf.conf and run pfctl -e -f /etc/pf.conf. In this example en3 and en0 are my ethernet and wifi interfaces

scrub-anchor "com.apple/*"
nat-anchor "com.apple/*"
rdr-anchor "com.apple/*"
nat on {en3, en0} proto {tcp, udp, icmp} from 192.168.56.0/24 to any -> {en3, en0}
pass from {lo0, 192.168.56.0/24} to any keep state
dummynet-anchor "com.apple/*"
anchor "com.apple/*"
load anchor "com.apple" from "/etc/pf.anchors/com.apple"