If you recall from previous chapters, IP addresses are not assigned directly to instances. Instead, an IP address is associated with a Neutron port, and that port is logically mapped to the virtual tap interface that connects instances to the network.

A floating IP, when used, is associated with a Neutron port. To create a floating IP from within the CLI, use the Neutron floatingip-create command as follows:

Syntax: floatingip-create [--tenant-id TENANT_ID]
[--port-id PORT_ID] [--fixed-ip-address FIXED_IP_ADDRESS] FLOATING_NETWORK

Floating IP addresses are usable only within the tenant that created them. An administrator is able to create floating IPs on behalf of tenants....