Floating public IP
Floating IPs are public IPv4 addresses that enable access to the Internet from an instance inside a tenant. Two floating IPs are accessible from each tenant by default, which is considered sufficient for most networking situations and workloads.
IPv4 addresses is a scarce resource, so rather than allocating a separate address to each server, one IPv4 address is used for server management through a bastion host and the other for service delivery through a load balancer or reverse proxy server. For details on how to implement and configure such a network, please see Configure network
Initially, the floating IPs need to be allocated to the tenant from a common address pool. A floating IP address has the following properties:
It can be used immediately: No routing information needs to be exchanged - the mapping between the floating IP address and the VM (its private address) is done by an instance of Contrail L3 agent in the Pan-Net cloud.
It can instantly be re-assigned and re-allocated within the same site by OpenStack commands.
More information about the floating IP concept can be found under Concepts in Floating IP