Re: [Qemu-devel] macvlan/macvtap: guest/host cannot communicate when network cable is unplugged
From: Stefan Hajnoczi <hidden>
Date: 2012-08-30 12:53:29
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qemu-devel
On Thu, Aug 30, 2012 at 1:13 PM, ching [off-list ref] wrote:
quoted hunk ↗ jump to hunk
quoted
Can you try the same test with two macvlan interfaces on the host (no macvtap)? You may need to use the ping -I <interface-address> argument to force the ping source address to a specific macvlan interface. If you see the same problem, it may just be the macvlan design - it is stacked on top of eth0 and might not work when eth0 is down. CCing macvlan/macvtap folks. Stefantested as below $ifconfig eth0 Link encap:Ethernet HWaddr f4:6d:xx:xx:xx:xx inet6 addr: fe80::xx:xx:xx:xx/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:86507 errors:0 dropped:0 overruns:0 frame:0 TX packets:55940 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:126005746 (120.1 MiB) TX bytes:4394225 (4.1 MiB) macvtap0 Link encap:Ethernet HWaddr 52:54:xx:xx:xx:xx inet6 addr: fe80::xx:xx:xx:xx/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:70 errors:0 dropped:0 overruns:0 frame:0 TX packets:84 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:500 RX bytes:9036 (8.8 KiB) TX bytes:14734 (14.3 KiB) znet0 Link encap:Ethernet HWaddr 00:60:xx:xx:xx:92 inet addr:192.168.1.2 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: 2002:xx:xx:xx:xx/64 Scope:Global inet6 addr: fe80:xx:xx:xx:xx/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:4463190 errors:0 dropped:0 overruns:0 frame:0 TX packets:12527522 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:3959213697 (3.6 GiB) TX bytes:18590336476 (17.3 GiB) znet1 Link encap:Ethernet HWaddr 00:60:xx:xx:xx:99 inet addr:192.168.1.177 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: 2002:xx:xx:xx:xx64 Scope:Global inet6 addr: fe80:xx:xx:xx:xx/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:8 errors:0 dropped:0 overruns:0 frame:0 TX packets:9 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:1399 (1.3 KiB) TX bytes:1522 (1.4 KiB) $ ip -d link show 10: znet0@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT link/ether 00:60:xx:xx:xx:92 brd ff:ff:ff:ff:ff:ff macvlan mode bridge 15: znet1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT link/ether 00:60:xx:xx:xx:99 brd ff:ff:ff:ff:ff:ff macvlan mode bridge the macvlan interface cannot ping each other no matter network cable is plugged or not $ ping -I 192.168.1.2 192.168.1.177 PING 192.168.1.177 (192.168.1.177) from 192.168.1.2 : 56(84) bytes of data.--- 192.168.1.177 ping statistics ---6 packets transmitted, 0 received, 100% packet loss, time 4999ms
In bridge mode I expected them to be able to communicate.
I also perform an additional test: the guests (macvtap bridge mode) CAN communicate each other no matter network cable is plugged or not.
Strange. I thought the original problem was that the macvtap guests cannot communicate with each other when the network cable is unplugged? Hopefully someone else can help you, I'm not familiar enough with macvlan/macvtap. Stefan