理解openstack中与虚拟机相关一些简单网络知识-2.veth pair

     

介绍

Virtual Ethernet Pair简称veth pair,是一个成对的端口,所有从这对端口一端进入的数据包都将从另一端出来,反之也是一样.

下面用例子说明vethpair的创建和使用:

现在有这样一个环境,两个网桥,一个是Linux内核网桥br1,另一个是ovs网桥
br-eth1,现在想把两个网桥连接起来,就可以用veth pair.

+------------------+ +------------------+
| | | |
| ovs bridge | | Linux bridge |
| br-eth1 | | br1 |
| | | |
+------------------+ +------------------+

首先创建一对vethpair:

# ip link add eth1-br1 type veth peer name phy-br1
# ip link list

...

25: phy-br1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT qlen 1000
link/ether 22:83:01:db:37:b4 brd ff:ff:ff:ff:ff:ff
26: eth1-br1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT qlen 1000
link/ether 32:b2:aa:1a:8a:13 brd ff:ff:ff:ff:ff:ff
创建成功后,可以通过ip link看到一对端口,可以通过ethtool查看他们是否成 对:
# ethtool -S phy-br1
NIC statistics:
peer_ifindex: 26

创建成功后,就可以分别将两个端口添加到不同的网桥上:

linux网桥

# brctl addif br1 phy-br1
# brctl show
bridge name bridge id STP enabled interfaces
br0 8000.e41f136dc9f0 no enp11s0f0
vnet0
vnet2
vnet3
br1 8000.deef26d9c76a no phy-br1
vnet1
vnet4

可以看到phy-br1添加到了br1网桥上.

ovs网桥

# ovs-vsctl add-port br-eth1 eth1-br1
# ovs-vsctl show
e61b93e6-a701-4b6e-86c2-05f883885ab8
Bridge br-int
fail_mode: secure
Port "qvof01b51bf-71"
tag: 1
Interface "qvof01b51bf-71"
Port "int-br-eth1"
Interface "int-br-eth1"
Port br-int
Interface br-int
type: internal
Bridge "br-eth1"
Port "eth1-br1"
Interface "eth1-br1"
Port "eth1"
Interface "eth1"
Port "phy-br-eth1"
Interface "phy-br-eth1"
Port "br-eth1"
Interface "br-eth1"
type: internal
ovs_version: "2.3.0"

可以看到eth1-br1也添加到了br-eth1网桥上了.这样整个网络就完成了网桥的连接:

+------------------+              +------------------+
|  ovs bridge      |              |   Linux bridge   |
|  br-eth1         |              |   br1            |
|       +----------+              +----------+       |
|       | eth1-br1 +--------------+ phy-br1  |       |
+-------+----------+              +----------+-------+

参考链接
http://blog.csdn.net/ztguang/article/details/56479154