auto eth0
iface eth0 inet static
address 192.168.0.21
gateway 192.168.0.1
netmask 255.255.255.0
dns-nameservers 192.168.0.1
auto eth1
iface eth1 inet static
address 192.168.1.21
gateway 192.168.0.1
netmask 255.255.255.0
dns-nameservers 192.168.0.1
auto eth2
iface eth2 inet manual
up ip link set dev $IFACE up
down ip link set dev $IFACE down
br-ex Link encap:Ethernet HWaddr 0a:45:d7:ce:c5:45
BROADCAST MULTICAST MTU:1500 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)
br-int Link encap:Ethernet HWaddr 8e:6c:da:0c:7c:4c
BROADCAST MULTICAST MTU:1500 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)
eth0 Link encap:Ethernet HWaddr 00:0c:29:0e:c1:66
inet addr:192.168.0.21 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fe0e:c166/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:65846 errors:0 dropped:0 overruns:0 frame:0
TX packets:25384 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:40230877 (40.2 MB) TX bytes:2617693 (2.6 MB)
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:16546 errors:0 dropped:0 overruns:0 frame:0
TX packets:16546 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:830892 (830.8 KB) TX bytes:830892 (830.8 KB)
ovs-system Link encap:Ethernet HWaddr 2e:19:95:31:93:8f
BROADCAST MULTICAST MTU:1500 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)
首先你要选择桥接模式， 其次要将eth1 和eth2 配置成和 物理机器网卡同一网段即可。 比较重要的是需要关闭防火墙。。
把你配置的网络up一下
eth2的配置我没看懂，但是你eth1的配置中网卡地址和网关以及dns都不在同一网段，肯定会出问题，除非你配置了路由表。将eth1的地址改为和网关和dns同一网段，并且可以ping通，然后重启一下网络服务看看