RTNETLINK 答案：使用帶有 tc 的 netem 時文件存在

因此，當我在主 VM 中輸入此命令時，我只會收到此錯誤：

sudo tc qdisc add dev eth0 root netem delay 97ms
RTNETLINK answers: File exists

知道如何解決嗎？

我在 Ubuntu 中執行這個命令：

uname -a
Linux anmol-vm1-new 3.13.0-46-generic #79-Ubuntu SMP Tue Mar 10 20:06:50 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
ubuntu@anmol-vm1-new:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 14.04.2 LTS
Release:    14.04
Codename:   trusty

這是/etc/network/interfaces文件的內容：

auto lo
iface lo inet loopback
source /etc/network/interfaces.d/*.cfg


ls /etc/network/interfaces.d/
eth0.cfg

這就是我所擁有的/etc/network/interfaces.d/eth0.cfg

# The primary network interface
auto eth0
iface eth0 inet dhcp

另外我得到這些錯誤：

ubuntu@anmol-vm1-new:/home/hadoop/yarnpp/workloads/RESULTS$ tc qdisc change dev eth0 root netem delay 100ms
RTNETLINK answers: Operation not permitted
ubuntu@anmol-vm1-new:/home/hadoop/yarnpp/workloads/RESULTS$ sudo tc qdisc change dev eth0 root netem delay 100ms
RTNETLINK answers: Invalid argument

作為參考，您可能還想查看我要求限制頻寬的這個StackOverflow 問題。

ifconfig -a
eth0      Link encap:Ethernet  HWaddr fa:16:3e:b4:22:7c  
         inet addr:10.0.1.190  Bcast:10.0.1.255  Mask:255.255.255.0
         inet6 addr: fe80::f816:3eff:feb4:227c/64 Scope:Link
         UP BROADCAST RUNNING MULTICAST  MTU:1454  Metric:1
         RX packets:603022138 errors:0 dropped:0 overruns:0 frame:0
         TX packets:132788011 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:1000 
         RX bytes:633486216278 (633.4 GB)  TX bytes:798520828666 (798.5 GB)

lo        Link encap:Local Loopback  
         inet addr:127.0.0.1  Mask:255.0.0.0
         inet6 addr: ::1/128 Scope:Host
         UP LOOPBACK RUNNING  MTU:65536  Metric:1
         RX packets:367293839 errors:0 dropped:0 overruns:0 frame:0
         TX packets:367293839 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:0 
         RX bytes:547056723183 (547.0 GB)  TX bytes:547056723183 (547.0 GB)

解決方案如下：

sudo tc qdisc del dev eth0 root
sudo tc qdisc add dev eth0 root netem delay 100ms

更短的解決方案：

sudo tc qdisc replace dev eth0 root netem delay 100ms

引用自：https://serverfault.com/questions/743885