When plugin constructs a ComputerLauncher object is uses Openstack.getPublicAddressIpv4(...) method which returns only available IPv4 address or null if nothing (including floating) found.

If Openstack instance provides only IPv6 address (-es), this can't work because none IPv4 address is available although the instance is reachable via IPv6.

The fix is to use Openstack.getPublicAddress(...) instead, but is should be refactored to prefer (hard-coded now) IPv4 over IPv6 and use IPv6 only if nothing else (floating, IPv4 etc.) isn't available.

Currently hard-coded preference order can be tweaked and made configurable later.