Docker网络基础之单机原理

基本原理

单机版多容器实例网络交互原理

• 在宿主机上面打开两张网卡eth0与eth1，打通两张网卡的链路
• 在test1上面启动一个veth网卡，创建一个namespace；并桥接到eth0上面
• 在test2上面启动一个veth网卡，创建一个namespace；并桥接到eth1上面
• 对test1与test2进行地址配置
• 测试网络交互情况

模拟实验

添加两个namespace

[root@host-2 ~]# ip netns add test1
[root@host-2 ~]# ip netns add test2

查看添加状况

[root@host-2 ~]# ip netns list
test2
test1

[root@host-2 ~]# ip netns exec test1 ip addr
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
[root@host-2 ~]# ip netns exec test2 ip addr
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

    PS：这里可以看到namespace还没有mac地址

添加一对虚拟网卡

[root@host-2 ~]# ip link add veth-test1 type veth peer name veth-test2

对虚拟网卡与namespace做捆绑

[root@host-2 ~]# ip link set veth-test1 netns test1
[root@host-2 ~]# ip link set veth-test2 netns test2

对namespace中的虚拟网卡做地址设定，并激活

[root@host-2 ~]# ip netns exec test1 ip addr add 10.1.1.100/24 dev veth-test1
[root@host-2 ~]# ip netns exec test2 ip addr add 10.1.1.200/24 dev veth-test2
[root@host-2 ~]# ip netns exec test1 ip link set dev veth-test1 up
[root@host-2 ~]# ip netns exec test2 ip link set dev veth-test2 up

查看设置的状况

[root@host-2 ~]# ip netns exec test1 ip addr
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
9: veth-test1@if8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether f2:c2:eb:2b:08:d6 brd ff:ff:ff:ff:ff:ff link-netnsid 1
    inet 10.1.1.100/24 scope global veth-test1
       valid_lft forever preferred_lft forever
    inet6 fe80::f0c2:ebff:fe2b:8d6/64 scope link 
       valid_lft forever preferred_lft forever
       
[root@host-2 ~]# ip netns exec test2 ip addr
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
8: veth-test2@if9: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 5e:06:df:2b:3d:fe brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 10.1.1.200/24 scope global veth-test2
       valid_lft forever preferred_lft forever
    inet6 fe80::5c06:dfff:fe2b:3dfe/64 scope link 
       valid_lft forever preferred_lft forever

测试实验结果

[root@host-2 ~]# ip netns exec test1 ping 10.1.1.200
PING 10.1.1.200 (10.1.1.200) 56(84) bytes of data.
64 bytes from 10.1.1.200: icmp_seq=1 ttl=64 time=0.141 ms
^C
--- 10.1.1.200 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.141/0.141/0.141/0.000 ms