Method usage

src/slave/containerizer/mesos/isolators/network/port_mapping.cpp:3128–3254

Future<ResourceStatistics> PortMappingIsolatorProcess::usage(
    const ContainerID& containerId)
{
  ResourceStatistics result;

  // Do nothing for unmanaged container.
  if (unmanaged.contains(containerId)) {
    return result;
  }

  if (!infos.contains(containerId)) {
    VLOG(1) << "Unknown container " << containerId;
    return result;
  }

  Info* info = CHECK_NOTNULL(infos[containerId]);

  if (info->pid.isNone()) {
    return result;
  }

  Result<hashmap<string, uint64_t>> stat =
    link::statistics(veth(info->pid.get()));

  if (stat.isError()) {
    return Failure(
        "Failed to retrieve statistics on link " +
        veth(info->pid.get()) + ": " + stat.error());
  } else if (stat.isNone()) {
    return Failure("Failed to find link: " + veth(info->pid.get()));
  }

  // Note: The RX/TX statistics on the two ends of the veth are the
  // exact opposite, because of its 'tunnel' nature. We sample on the
  // host end of the veth pair, which means we have to reverse RX and
  // TX to reflect statistics inside the container.

  // +----------+                    +----------+
  // |          |                    |          |
  // |          |RX<--------------+TX|          |
  // |          |                    |          |
  // |   veth   |                    |   eth0   |
  // |          |                    |          |
  // |          |TX+-------------->RX|          |
  // |          |                    |          |
  // +----------+                    +----------+

  Option<uint64_t> rx_packets = stat->get("tx_packets");
  if (rx_packets.isSome()) {
    result.set_net_rx_packets(rx_packets.get());
  }

  Option<uint64_t> rx_bytes = stat->get("tx_bytes");
  if (rx_bytes.isSome()) {
    result.set_net_rx_bytes(rx_bytes.get());
  }

  Option<uint64_t> rx_errors = stat->get("tx_errors");