IPv6AllocCIDR is the range of IPv6 addresses in the CIDR format that the external workload can
use to allocate IP addresses for the tunnel device and the health endpoint.
pattern: ^s*((([0-9A-Fa-f]{1,4}:){7}(:|([0-9A-Fa-f]{1,4})))|(([0-9A-Fa-f]{1,4}:){6}:([0-9A-Fa-f]{1,4})?)|(([0-9A-Fa-f]{1,4}:){5}(((:[0-9A-Fa-f]{1,4}){0,1}):([0-9A-Fa-f]{1,4})?))|(([0-9A-Fa-f]{1,4}:){4}(((:[0-9A-Fa-f]{1,4}){0,2}):([0-9A-Fa-f]{1,4})?))|(([0-9A-Fa-f]{1,4}:){3}(((:[0-9A-Fa-f]{1,4}){0,3}):([0-9A-Fa-f]{1,4})?))|(([0-9A-Fa-f]{1,4}:){2}(((:[0-9A-Fa-f]{1,4}){0,4}):([0-9A-Fa-f]{1,4})?))|(([0-9A-Fa-f]{1,4}:){1}(((:[0-9A-Fa-f]{1,4}){0,5}):([0-9A-Fa-f]{1,4})?))|(:(:|((:[0-9A-Fa-f]{1,4}){1,7}))))(%.+)?s*/([0-9]|[1-9][0-9]|1[0-1][0-9]|12[0-8])$