OpenStack Networking has the concept of Fixed IPs and Floating IPs. Fixed IPs are assigned to an instance on creation and stay the same until the instance is explicitly terminated. Floating ips are ip addresses that can be dynamically associated with an instance. This address can be disassociated and associated with another instance at any time. Various tasks carried out by Floating IP's as of now. create IP ranges under a certain group, only available for admin role. allocate an floating IP to a certain tenant, only available for admin role. deallocate an floating IP from a certain tenant associate an floating IP to a given instance disassociate an floating IP from a certain instance Just as shown by the above figure, we will have nova-network-api to support nova client floating commands. nova-network-api will invoke neutron cli lib to interactive with neutron server via API. The data about floating IPs will be stored in to neutron DB. Neutron Agent, which is running on compute host will enforce the floating IP. Multiple Floating IP Pools The L3 API in OpenStack Networking supports multiple floating IP pools. In OpenStack Networking, a floating IP pool is represented as an external network and a floating IP is allocated from a subnet associated with the external network. Since each L3 agent can be associated with at most one external network, we need to invoke multiple L3 agent to define multiple floating IP pools. 'gateway_external_network_id'in L3 agent configuration file indicates the external network that the L3 agent handles. You can run multiple L3 agent instances on one host. In addition, when you run multiple L3 agents, make sure that handle_internal_only_routers is set to Trueonly for one L3 agent in an OpenStack Networking deployment and set to Falsefor all other L3 agents. Since the default value of this parameter is True, you need to configure it carefully. Before starting L3 agents, you need to create routers and external networks, then update the configuration files with UUID of external networks and start L3 agents. For the first agent, invoke it with the following l3_agent.ini where handle_internal_only_routers is True.