Synnefo » snf-ganeti

  @staticmethod

  def _GenerateTapName(nic):

    """Generate a TAP network interface name for a NIC.

    This helper function generates a special TAP network interface

    name for NICs that are meant to be used in instance communication.

    This function checks the existing TAP interfaces in order to find

    a unique name for the new TAP network interface.  The TAP network

    interface names are of the form 'gnt.com.%d', where '%d' is a

    unique number within the node.

    @type nic: ganeti.objects.NIC

    @param nic: NIC object for the name should be generated

    @rtype: string

    @return: TAP network interface name, or the empty string if the

             NIC is not used in instance communication

    """

    if nic.name is None or not \

          nic.name.startswith(constants.INSTANCE_COMMUNICATION_NIC_PREFIX):

      return ""

    result = utils.RunCmd(["ip", "tuntap", "list"])

    if result.failed:

      raise errors.HypervisorError("Failed to list TUN/TAP interfaces")

    idxs = set()

    for line in result.output.splitlines():

      parts = line.split(": ", 1)

      if len(parts) < 2:

        raise errors.HypervisorError("Failed to parse TUN/TAP interfaces")

      r = re.match(r"gnt\.com\.([0-9]+)", parts[0])

      if r is not None:

        idxs.add(int(r.group(1)))

    if idxs:

      idx = max(idxs) + 1

    else:

      idx = 0

    return "gnt.com.%d" % idx

        tapname, tapfd = _OpenTap(vnet_hdr=vnet_hdr,

                                  name=self._GenerateTapName(nic))

-- * Instance communication

instanceCommunicationNetwork :: String

instanceCommunicationNetwork = "ganeti:network:communication"

instanceCommunicationNicPrefix :: String

instanceCommunicationNicPrefix = "ganeti:communication:"