code: func (plugin *kubenetNetworkPlugin) disableContainerDAD(id kubecontainer.ContainerID) error {
  	key := "net/ipv6/conf/default/dad_transmits"
  
  	sysctlBin, err := plugin.execer.LookPath("sysctl")
  	if err != nil {
  		return fmt.Errorf("Could not find sysctl binary: %s", err)
  	}
  
  	netnsPath, err := plugin.host.GetNetNS(id.ID)
  	if err != nil {
  		return fmt.Errorf("Failed to get netns: %v", err)
  	}
  	if netnsPath == "" {
  		return fmt.Errorf("Pod has no network namespace")
  	}
  
  	// If the sysctl doesn't exist, it means ipv6 is disabled; log and move on
  	if _, err := plugin.sysctl.GetSysctl(key); err != nil {
  		return fmt.Errorf("Ipv6 not enabled: %v", err)
  	}
  
  	output, err := plugin.execer.Command(plugin.nsenterPath,
  		fmt.Sprintf("--net=%s", netnsPath), "-F", "--",
  		sysctlBin, "-w", fmt.Sprintf("%s=%s", key, "0"),
  	).CombinedOutput()
  	if err != nil {
  		return fmt.Errorf("Failed to write sysctl: output: %s error: %s",
  			output, err)
  	}
  	return nil
  }
docs: // disableContainerDAD disables duplicate address detection in the container.
  // DAD has a negative affect on pod creation latency, since we have to wait
  // a second or more for the addresses to leave the "tentative" state. Since
  // we're sure there won't be an address conflict (since we manage them manually),
  // this is safe. See issue 54651.
  //
  // This sets net.ipv6.conf.default.dad_transmits to 0. It must be run *before*
  // the CNI plugins are run.