// and host bits. For example an IPv4 address of 192.168.0.0/24, splits the
  // address into 24 bits for the network portion and 8 bits for the host portion.
  // To allocate 256 IPs, set this field to 8 (a /24 mask for IPv4 or a /120 for IPv6).
  // Minimum value is 4 (16 IPs).
  // This field is immutable.
  // +required
  optional int32 perNodeHostBits = 2;

  // ipv4 defines an IPv4 IP block in CIDR notation(e.g. "10.0.0.0/8").