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| From: | Davide Baldini |
| Subject: | Re: [Qemu-discuss] Guest fails to reconnect after host network goes down |
| Date: | Sun, 23 Aug 2015 13:31:28 +0200 |
| User-agent: | Mozilla/5.0 (X11; Linux i686; rv:31.0) Gecko/20100101 Icedove/31.6.0 |
Thanks Vlad,apparently everything is fine on `ifconfig` after the ethernet cable is unplugged and re-plugged; I don't see what is wrong:
Before unplugging the cable – guests network works:
—————————————————————————————————————————————————————————————
address@hidden:/home/davide# ifconfig
br0 Link encap:Ethernet HWaddr 00:30:48:34:ba:66
inet addr:192.168.1.10 Bcast:192.168.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1240 errors:0 dropped:0 overruns:0 frame:0
TX packets:1100 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:119495 (116.6 KiB) TX bytes:120045 (117.2 KiB)
eth1 Link encap:Ethernet HWaddr 00:30:48:34:ba:66
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2194 errors:0 dropped:0 overruns:0 frame:0
TX packets:2146 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:962419 (939.8 KiB) TX bytes:282788 (276.1 KiB)
Interrupt:18 Memory:d8000000-d8020000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
tap0 Link encap:Ethernet HWaddr fe:48:f3:d7:e7:a8
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:32 errors:0 dropped:0 overruns:0 frame:0
TX packets:111 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:3120 (3.0 KiB) TX bytes:19977 (19.5 KiB)
tap1 Link encap:Ethernet HWaddr fe:4a:01:97:86:22
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:957 errors:0 dropped:0 overruns:0 frame:0
TX packets:1094 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:142946 (139.5 KiB) TX bytes:841308 (821.5 KiB)
tap2 Link encap:Ethernet HWaddr fe:8e:6b:11:a4:2a
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:56 errors:0 dropped:0 overruns:0 frame:0
TX packets:58 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:7367 (7.1 KiB) TX bytes:12866 (12.5 KiB)
After unplug and replug — guests network stops working, host's works:
—————————————————————————————————————————————————————————————
address@hidden:/home/davide# ifconfig
br0 Link encap:Ethernet HWaddr 00:30:48:34:ba:66
inet addr:192.168.1.10 Bcast:192.168.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:207 errors:0 dropped:0 overruns:0 frame:0
TX packets:163 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:23747 (23.1 KiB) TX bytes:17026 (16.6 KiB)
eth1 Link encap:Ethernet HWaddr 00:30:48:34:ba:66
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2629 errors:0 dropped:0 overruns:0 frame:0
TX packets:2572 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1019843 (995.9 KiB) TX bytes:520666 (508.4 KiB)
Interrupt:18 Memory:d8000000-d8020000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
tap0 Link encap:Ethernet HWaddr fe:48:f3:d7:e7:a8
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:56 errors:0 dropped:0 overruns:0 frame:0
TX packets:124 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:5378 (5.2 KiB) TX bytes:21231 (20.7 KiB)
tap1 Link encap:Ethernet HWaddr fe:4a:01:97:86:22
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1102 errors:0 dropped:0 overruns:0 frame:0
TX packets:1232 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:347548 (339.4 KiB) TX bytes:862119 (841.9 KiB)
tap2 Link encap:Ethernet HWaddr fe:8e:6b:11:a4:2a
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:56 errors:0 dropped:0 overruns:0 frame:0
TX packets:63 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:7367 (7.1 KiB) TX bytes:13524 (13.2 KiB)
—————————————————————————————————————————————————————————————
As far as I notice, there are no differences shown by `ifconfig`.
The fact is, that all guests drop the network after a cable is unplugged
and then replugged, while the host's network keeps functioning.
Where else can I look? -- Davide On 08/19/2015 08:02 PM, Vlad Yasevich wrote:
On 08/16/2015 12:55 PM, Davide Baldini wrote:When I unplug the ethernet cable from the physical host, guest fails to reconnect; host does reconnect.What do you mean by 'reconnect'? Unplugging the cable for the nic on the physical host does not really disconnect the guest from the network. According to the configuration your provided, the guest is still connected to the bridge on the host and can still communicate with other guests on the same host. Once the host network is plugged back in, the bridge should start forwarding packets back to the guest.A very simple configuration here, with an almost default Debian 7 on both host and guest: -- ON HOST: /etc/network/interfaces auto lo iface lo inet loopback auto br0 iface br0 inet dhcp bridge_ports eth1 bridge_stp off bridge_maxwait 0 bridge_fd 0 -- ON GUEST: /etc/network/interfaces auto eth0 allow-hotplug eth0 iface eth0 inet static address 192.168.1.109 netmask 255.255.255.0 network 192.168.1.0 broadcast 192.168.1.255 gateway 192.168.1.1 dns-nameservers 192.168.1.1 QEMU is started as: /usr/local/bin/qemu-system-x86_64 -hda /media/raid1/qemu-109 -m 8G -smp 4 -enable-kvm -netdev bridge,id=br109 -device virtio-net-pci,netdev=br109,id=nic0,mac=00:00:00:00:01:09 -k it -daemonize QEMU emulator version 2.3.0 Nothing appears on dmesg. Any hints?Make sure that the bridge on the host is formed correctly after the cable has been plugged back in. -vlad-- Davide
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