[Qemu-devel] Multiple Qemu Instances

[Volkan YAZICI]

Hi,

While trying to run two qemu instances on a single server with a single
NIC, I'm having network related problems. When I start the second qemu
instance, ping'ing both servers concurrently works like below:

  ping 192.168.1.11                    ping 192.168.1.14
  -------------------------------      -------------------------------
  10 packets transmitted.             Waking up...
  Packets get started to lost.        10 packets transmitted. (No loss.)
  10 packets transmitted. (No loss.)  Packets get started to lost.
  Packets get started to lost.        10 packets transmitted. (No loss.)
  10 packets transmitted. (No loss.)  Packets get started to lost.
  Packets get started to lost.        10 packets transmitted. (No loss.)
  10 packets transmitted. (No loss.)  Packets get started to lost.
  ...                                 ...

Related configurations are listed below.

  $ ifconfig -a 
  br0       Link encap:Ethernet  HWaddr 00:1A:64:C1:94:3C
            inet addr:192.168.1.10  Bcast:192.168.1.255  Mask:255.255.255.0
            inet6 addr: fe80::21a:64ff:fec1:943c/64 Scope:Link
            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
            RX packets:57580386 errors:0 dropped:0 overruns:0 frame:0
            TX packets:50256481 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:0
            RX bytes:7292961440 (6.7 GiB)  TX bytes:28958593591 (26.9 GiB)
  
  eth0      Link encap:Ethernet  HWaddr 00:1A:64:C1:94:3C
            inet6 addr: fe80::21a:64ff:fec1:943c/64 Scope:Link
            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
            RX packets:545421613 errors:0 dropped:0 overruns:0 frame:0
            TX packets:508159417 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:1000
            RX bytes:518992547535 (483.3 GiB)  TX bytes:386017012654 (359.5 GiB)
            Interrupt:106 Memory:ce000000-ce011100
  
  tap0      Link encap:Ethernet  HWaddr 82:CE:FE:4D:9F:24
            inet6 addr: fe80::80ce:feff:fe4d:9f24/64 Scope:Link
            UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500 Metric:1
            RX packets:74724106 errors:0 dropped:0 overruns:0 frame:0
            TX packets:112203767 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:500
            RX bytes:8410033346 (7.8 GiB)  TX bytes:151553233037 (141.1 GiB)
  
  tap1      Link encap:Ethernet  HWaddr A6:29:D5:36:3D:2E
            inet6 addr: fe80::a429:d5ff:fe36:3d2e/64 Scope:Link
            UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500 Metric:1
            RX packets:139 errors:0 dropped:0 overruns:0 frame:0
            TX packets:388 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:500
            RX bytes:66530 (64.9 KiB)  TX bytes:123439 (120.5 KiB)
  
  $ cat /etc/qemu-ifup
  #!/bin/sh
  
  IFACE=$1
  
  /sbin/ifconfig $IFACE 0.0.0.0 promisc up
  /usr/sbin/brctl addif br0 $IFACE
  
  $ cat /etc/qemu-ifdown
  #!/bin/sh
  
  IFACE=$1
  
  /sbin/ifconfig $IFACE 0.0.0.0 promisc down
  /usr/sbin/brctl delif br0 $IFACE

I start qemu using a command similar to below

  /usr/local/bin/qemu-system-x86_64 ... -net nic -net tap

Does anybody have an idea about what might be causing the problem? How
can I deploy two qemu instances sharing physically same NICs?


Regards.