Network verification: Not enough IP addresses. Public network must have at least 5 IP addresses for the current environment.

[Timur Nurlygayanov]

Stesps To Reproduce:
1. Create OpenStack cluster with 3 controllers and 2 compute nodes with HA configuration and configure Public IP range with only one address.
2. Save configuration and start network verification. Verify that network is OK.
3. Click on Save Configuration. Start OpenStack cloud deploy.

Observed Result:
Error: Not enough IP addresses. Public network must have at least 5 IP addresses for the current environment.

[Andrew Woodward (xarses)]

Actually, you need 6.

Currently it is by design that a public IP is required for each node. This was initially due to support for Nova networks which requires this. The decision has been made to leave this in place as it will likely become necessary with Neutron DVR. Additionally the advanced networking blueprint may attempt to alleviate some of this need, for example storage nodes dont need public addresses at all.

[Kevin Nguyen (huykevin)]

In my test grid (3 controllers + 1 compute + 1 storage node) I have to use 7 public IPs. Can someone explain why is it?
Thank you.