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satimis 10th December 2009 05:00

KVM Guest - Networking problem
 
Hi folks,


KVM
Host - Debian 5.0
VM (Guest) - Ubuntu 9.10
One NIC


I ran following command to create the guest (VM).

$ sudo virt-install --connect qemu:///system -n vm30ubuntu910 -r 512 --vcpus=2 -f /home/satimis/VM/vm30ubuntu910.qcow2 -s 12 -c /home/satimis/Desktop/mini_ubuntu9.10.iso --vnc --noautoconsole --os-type linux --accelerate --network=bridge:br0 --hvm


It went through without problem. Guest can contact Internet with following settings on /etc/network/interfaces
Code:


auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet dhcp


The above settings was created automatically during installation.


I tried setting following static IP without success;
Code:


# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet manual

auto br0
iface br0 inet static
        address        192.168.0.30
        netmask        255.255.255.0
        network        192.168.0.0
        broadcast      192.168.0.255
        gateway        192.168.0.1
        bridge_ports    eth0
        bridge_fd      9
        bridge_hello    2
        bridge_maxage  12
        bridge_stp      off


Internet can't be connected.


On guest;

sudo ifconfig eth0 :-
Code:

eth0    Link encap: Ethernet  HWaddr 54:52:00:07:69:c8
    Broadcase multicast  MTU:1500  Metric:1
    RX packets:0 errors:0 dropped:0 ovrruns:0 frame:0
    TX packets:0 errors:0 dropped:0 ovrruns:0 carrier:0 
    collisions:0 txqueuelen:1000
    RX bytes:0 (0.0 B)  TX bytes:0 (0.0.B)
    Interrupt:10


$ netstat -rn :-
Code:

Kernel IP routing table
Destination  Gateway  Genmask  Flags  MSS Window  irtt  Iface


complete ip route from host

$ ip route
Code:


192.168.0.0/24 dev br0  proto kernel  scope link  src 192.168.0.10
192.168.122.0/24 dev virbr0  proto kernel  scope link  src 192.168.122.1
default via 192.168.0.1 dev br0


complete ip route from guest

$ ip route
Code:

192.168.0.0/24 dev eth0  proto kernel  scope link  src 192.168.0.49
default via 192.168.0.1 dev eth0  metric 100


complete ip link from host

$ ip link
Code:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000
    link/ether 00:0e:a6:f9:a3:5b brd ff:ff:ff:ff:ff:ff
3: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN
    link/ether 00:0e:a6:f9:a3:5b brd ff:ff:ff:ff:ff:ff
4: virbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN
    link/ether fa:cc:db:5d:a5:63 brd ff:ff:ff:ff:ff:ff
5: vnet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 500
    link/ether 00:ff:95:46:91:b5 brd ff:ff:ff:ff:ff:ff
6: vnet1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 500
    link/ether 00:ff:00:13:7d:6d brd ff:ff:ff:ff:ff:ff
7: vnet2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 500
    link/ether 00:ff:e9:57:bf:64 brd ff:ff:ff:ff:ff:ff


complete ip link from guest

$ ip link
Code:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 54:52:00:07:69:c8 brd ff:ff:ff:ff:ff:ff


On host

$ sudo brctl show
Code:


bridge name    bridge id        STP enabled    interfaces
br0        8000.000ea6f9a35b    no        eth0
                            vnet0
                            vnet1
                            vnet2
virbr0        8000.000000000000    yes


Please help. TIA


Edit:

I found out the cause in running following command on VM (Guest)

$ sudo /etc/init.d/networking restart
Code:

* Reconfiguring network interfaces...                                   
 * if-up.d/mountnfs[eth0]: waiting for interface br0 before doing NFS mounts
SIOCSIFADDR: No such device
br0: ERROR while getting interface flags: No such device
SIOCSIFNETMASK: No such device
SIOCSIFBRDADDR: No such device
br0: ERROR while getting interface flags: No such device
br0: ERROR while getting interface flags: No such device
Failed to bring up br0.
                                                                  [ OK ]

IIRC I met this problem sometimes ago. I had it fixed later unfortunate I have no recollection. Any advice? Thanks


B.R.
satimis

torusturtle 8th May 2010 14:05

Check if you have either the file
/etc/iftab

or
/etc/udev/rules.d/70-persistent-net.rules (or similar)

The mac address in the file should be the same as you have configured for the kvm vm.

satimis 8th May 2010 15:13

Quote:

Originally Posted by torusturtle (Post 227627)
Check if you have either the file
/etc/iftab

or
/etc/udev/rules.d/70-persistent-net.rules (or similar)

The mac address in the file should be the same as you have configured for the kvm vm.

Hi torusturtle,

Thanks for your advice.

I fixed my problem already. IIRC it needs bridge-utils installed on the guest as well.


B.R.
satimis


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