Configuring Flat Networking

FlatNetworking uses ethernet adapters configured as bridges to allow network traffic to transit between all the various nodes. This setup can be done with a single adapter on the physical host, or multiple. This option does not require a switch that does VLAN tagging as VLAN networking does, and is a common development installation or proof of concept setup. When you choose Flat networking, Nova does not manage networking at all. Instead, IP addresses are injected into the instance via the file system (or passed in via a guest agent). Metadata forwarding must be configured manually on the gateway if it is required within your network.

To configure flat networking, ensure that your nova.conf file contains the following line:

network_manager=nova.network.manager.FlatManager
                

	Note
	When configuring Flat Networking, failing to enable flat_injected can prevent guest VMs from receiving their IP information at boot time.