Before launching your first instance, you must create the necessary virtual network infrastructure to which the instance will connect. This network typically provides internet access from instances. You can enable internet access to individual instances using a floating IP address and suitable security group rules. The admin tenant owns this network because it provides external network access for multiple tenants. This network shares the same subnet associated with the physical network connected to the external interface on the compute node. You should specify an exclusive slice of this subnet to prevent interference with other devices on the external network. Perform these commands on the controller node. Source the admin tenant credentials: $ source admin-openrc.sh Create the network: Replace NETWORK_CIDR with the subnet associated with the physical network. $ nova network-create demo-net --bridge br100 --multi-host T \ --fixed-range-v4 NETWORK_CIDR For example, using an exclusive slice of 203.0.113.0/24 with IP address range 203.0.113.24 to 203.0.113.32: $ nova network-create demo-net --bridge br100 --multi-host T \ --fixed-range-v4 203.0.113.24/29