Comment 4 for bug 1514810

When is the DHCP IP address allocated? I would think that if there are no IPs left, it would produce an error at that time. If that is done synchronously, I would think it is sufficient.

Adding an IPAM call that provides a count of available addresses for a given subnet would be useful in other ways beyond this, however. But that probably wouldn't be backport-eligible since it would essentially be adding a feature.