Description of problem:

When using RDO manager virt setup , there is no document on :

1. how to create external network for floating ip using default flat installation

source overcloudrc
 neutron net-create admin-ext --provider:network_type flat --providerhysical_network datacentre --router:external
 neutron subnet-create --name admin-ext-sub --disable-dhcp admin-ext 192.0.2.0/24 --allocation_pools list=true type=dict start=192.0.2.150,end=192.0.2.200 --gateway_ip=192.0.2.1


2. when using network isolation , there is no document how to create interface on the instack host to access the external network ( which is alreday documented )



1. Add interface in vlan 10 (external net) and assign it an IP from the
external net on the undercloud node:

$ ovs-vsctl add-port br-ctlplane vlan10 tag=10 -- set interface vlan10
   type=internal \
    ip l set dev vlan10 up; ip addr add 172.16.23.251/24 dev vlan10

2. Add masquerade rule for the external net subnet on undercloude node:

   $ iptables -A BOOTSTACK_MASQ -s 172.16.23.0/24 ! -d 172.16.23.0/24 -j
   MASQUERADE -t nat



Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1.
2.
3.

Actual results:


Expected results:


Additional info: