咱们知道：kvm虚构化环境装置好后，ifconfig会发现多了一个虚构网卡virbr 这是因为装置和启用了libvirt服务后生成的，libvirt在主机（host）上生成一个 virtual network switch (virbr)，host上一切的虚构机（guests）经过这个 virbr 连起来。自动状况下 virbr 经常使用的是 NAT 形式（驳回 IP Masquerade），所以这种状况下 guest 经过 host 能力访问外部。
然而大少数状况下： 咱们虚构机经常使用的是bridge（网桥）间接连到局域网里，所以这个 virbr 不是必定的（注：不要搞混杂了， bridge 和这里的 virbr bridge 是互不相干的 ）。
那么如何关掉这个 virbr 呢？
上方对封锁这个virbr虚构网卡的操作做一记载：
总结为以下三步： ）首先net-destroy ）接着net-undefine ）最后重启libvirtd让设置失效
[root@kvmserver ~]# br Link encap:Ethernet HWaddr C:F::F:FC:F inet addr:... Bcast:... Mask:... inet addr: fe::caf:ff:fef:fcf/ Scope:Link UP BROADCAST RUNNING MULTICAST MTU: Metric: RX packets: errors: dropped: overruns: frame: TX packets: errors: dropped: overruns: carrier: collisions: txqueuelen: RX bytes: (. MiB) TX bytes: (. MiB)
em Link encap:Ethernet HWaddr C:F::F:FC:E inet addr:... Bcast:... Mask:... inet addr: fe::caf:ff:fef:fce/ Scope:Link UP BROADCAST RUNNING MULTICAST MTU: Metric: RX packets: errors: dropped: overruns: frame: TX packets: errors: dropped: overruns: carrier: collisions: txqueuelen: RX bytes: (. MiB) TX bytes: (. MiB) Interrupt:
em Link encap:Ethernet HWaddr C:F::F:FC:F inet addr: fe::caf:ff:fef:fcf/ Scope:Link UP BROADCAST RUNNING MULTICAST MTU: Metric: RX packets: errors: dropped: overruns: frame: TX packets: errors: dropped: overruns: carrier: collisions: txqueuelen: RX bytes: (. MiB) TX bytes: (. MiB) Interrupt:
lo Link encap:Local Loopback inet addr:... Mask:... inet addr: ::/ Scope:Host UP LOOPBACK RUNNING MTU: Metric: RX packets: errors: dropped: overruns: frame: TX packets: errors: dropped: overruns: carrier: collisions: txqueuelen: RX bytes: (. MiB) TX bytes: (. MiB)
Link encap:Ethernet HWaddr :::E:D: inet addr: Bcast:... Mask:... UP BROADCAST RUNNING MULTICAST MTU: Metric: RX packets: errors: dropped: overruns: frame: TX packets: errors: dropped: overruns: carrier: collisions: txqueuelen: RX bytes: (. b) TX bytes: (. b)
[root@kvmserver ~]# bridge name bridge id STP enabled interfaces .cfffcf em .ed virbr-nic
[root@kvmserver ~]# virsh net-list Name State Autostart Persistent -------------------------------------------------- br active yes yes default yes yes
[root@kvmserver ~]# virsh net-destroy default Network default destroyed
[root@kvmserver ~]# virsh net-undefine default Network default has been undefined
[root@kvmserver ~]# service libvirtd restart Stopping libvirtd daemon: [ OK ] Starting libvirtd daemon: [ OK ] [root@kvmserver ~]# virsh net-list Name State Autostart Persistent -------------------------------------------------- br active yes yes
[root@kvmserver ~]# brctl show bridge name bridge id STP enabled interfaces br .cfffcf no em
再次ifconfig检查，发现virtbr网卡曾经隐没了！ [root@kvmserver ~]# ifconfig br Link encap:Ethernet HWaddr C:F::F:FC:F inet addr:... Bcast:... Mask:... inet addr: fe::caf:ff:fef:fcf/ Scope:Link UP BROADCAST RUNNING MULTICAST MTU: Metric: RX packets: errors: dropped: overruns: frame: TX packets: errors: dropped: overruns: carrier: collisions: txqueuelen: RX bytes: (. MiB) TX bytes: (. MiB)
em Link encap:Ethernet HWaddr C:F::F:FC:E inet addr:... Bcast:... Mask:... inet addr: fe::caf:ff:fef:fce/ Scope:Link UP BROADCAST RUNNING MULTICAST MTU: Metric: RX packets: errors: dropped: overruns: frame: TX packets: errors: dropped: overruns: carrier: collisions: txqueuelen: RX bytes: (. MiB) TX bytes: (. MiB) Interrupt:
em Link encap:Ethernet HWaddr C:F::F:FC:F inet addr: fe::caf:ff:fef:fcf/ Scope:Link UP BROADCAST RUNNING MULTICAST MTU: Metric: RX packets: errors: dropped: overruns: frame: TX packets: errors: dropped: overruns: carrier: collisions: txqueuelen: RX bytes: (. MiB) TX bytes: (. MiB) Interrupt:
lo Link encap:Local Loopback inet addr:... Mask:... inet addr: ::/ Scope:Host UP LOOPBACK RUNNING MTU: Metric: RX packets: errors: dropped: overruns: frame: TX packets: errors: dropped: overruns: carrier: collisions: txqueuelen: RX bytes: (. MiB) TX bytes: (. MiB)
