KVM(kernel-based VM)和它的伙伴（四）

上接
KVM(kernel-based VM)和它的伙伴（三）

重启后，test-network是inactive的

A>sudo virsh net-list  --all
 Name           State      Autostart   Persistent
---------------------------------------------------
 default        active     yes         yes
 test-network   inactive   no          yes

A>virsh net-edit default
获取default的配置详情，并得到可用于修改的缓存：
<network>
  <name>default</name>
  <uuid>20dd5a47-2c2d-4c18-a059-f854315527ab</uuid>
  <forward mode='nat'/>
  <bridge name='virbr0' stp='on' delay='0'/>
  <mac address='52:54:00:fa:a1:17'/>
  <ip address='192.168.122.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='192.168.122.2' end='192.168.122.254'/>
    </dhcp>
  </ip>
</network>

看看桥接网络

ip link show master virbr0
5: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel master virbr0 state DOWN mode DEFAULT group default qlen 1000
    link/ether 52:54:00:fa:a1:17 brd ff:ff:ff:ff:ff:ff

virbr0-nic是虚拟的，它存在的唯一意义是为它绑定到的bridge提供一个固定的MAC

它是NAT的。下面我们弄一个桥接的，先新建一个叫br0：
sudo ip link add br0 type bridge
sudo ip link show type bridge
4: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default qlen 1000
    link/ether 52:54:00:fa:a1:17 brd ff:ff:ff:ff:ff:ff
6: br0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether aa:fe:cb:16:09:ef brd ff:ff:ff:ff:ff:ff

然后加一个物理网络接口到bridge，加在用的网卡时注意，因为它会丢失自己的IP，导致断网。

A>sudo ip link set wlp2s0 up
A>sudo ip link set wlp2s0 master br0
Error: Device does not allow enslaving to a bridge.
试着加个无线网卡，不行。

还是得加有线网卡。
sudo ip link set enp1s0 master br0; sudo ip address add dev br0 192.168.198.?1/24

结果：连不上这台机器了。因为你没有让br0 up起来啊。还有将原网卡的gateway,dns等信息都给br0

参考
https://linuxconfig.org/how-to-use-bridged-networking-with-libvirt-and-kvm

#linux下操作网桥/网络的命令很多，下面是nmcli的

nmcli con show --active
nmcli con add ifname br0 type bridge con-name br0
nmcli con add type bridge-slave ifname enx000ec63b3186 master br0
nmcli con modify br0 ipv4.address '192.168.198.?1/24'
nmcli con modify br0 ipv4.gateway '192.168.198.1'
nmcli con modify br0 ipv4.dns '114.114.114.114'
nmcli con modify br0 ipv4.method manual
nmcli con up br0
ip a s br0