8.2. Creating the Overcloud External Network

You previously configured the node interfaces to use the External network in Section 6.2, “Isolating Networks”. However, you still need to create this network on the Overcloud so that you can assign floating IP addresses to instances.

Using a Native VLAN

This procedure assumes a dedicated interface or native VLAN for the External network.
Source the overcloud and create an External network in Neutron. For example:
$ source ~/overcloudrc
$ neutron net-create nova --router:external --provider:network_type flat --provider:physical_network datacentre
$ neutron subnet-create --name nova --enable_dhcp=False --allocation-pool=start=10.1.1.51,end=10.1.1.250 --gateway=10.1.1.1 nova 10.1.1.0/24
In this example, you create a network with the name nova. The Overcloud requires this specific name for the default floating IP pool. This is also important for the validation tests in Section 8.5, “Validating the Overcloud”.
This command also maps the network to the datacentre physical network. As a default, datacentre maps to the br-ex bridge. Leave this option as the default unless you have used custom neutron settings during the Overcloud creation.

Using a Non-Native VLAN

If not using the native VLAN, assign the network to a VLAN using the following commands:
$ source ~/overcloudrc
$ neutron net-create nova --router:external --provider:network_type vlan --provider:physical_network datacentre --provider:segmentation_id 104
$ neutron subnet-create --name nova --enable_dhcp=False --allocation-pool=start=10.1.1.51,end=10.1.1.250 --gateway=10.1.1.1 nova 10.1.1.0/24
The provider:segmentation_id value defines the VLAN to use. In this case, you can use 104.
Confirm the created network with neutron net-list:
$ neutron net-list
+-----------------------+-------------+---------------------------------------------------+
| id                    | name        | subnets                                           |
+-----------------------+-------------+---------------------------------------------------+
| d474fe1f-222d-4e32... | nova        | 01c5f621-1e0f-4b9d-9c30-7dc59592a52f 10.1.1.0/24  |
+-----------------------+-------------+---------------------------------------------------+