Docker0基本原理

Docker 服务默认会创建一个 docker0 网桥（evth-pair），它在内核层连通了其他的物理或虚拟网卡，这就将所有容器和本地主机都放到同一个物理网络。

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000

    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

    inet 127.0.0.1/8 scope host lo

       valid_lft forever preferred_lft forever

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000

    link/ether fa:16:3e:59:fd:3b brd ff:ff:ff:ff:ff:ff

    inet 172.29.67.55/24 brd 172.29.67.255 scope global dynamic eth0

       valid_lft 3152665450sec preferred_lft 3152665450sec

3: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default

    link/ether 02:42:29:85:de:4f brd ff:ff:ff:ff:ff:ff

    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0

       valid_lft forever preferred_lft forever

启动Docker容器的时候，Docker会给Docker容器分配一个IP

启动一个容器，会出现一对网卡

宿主机：

 497: vethf5da2d@if496: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP group default

    link/ether ba:6f:34:6e:3f:0f brd ff:ff:ff:ff:ff:ff link-netnsid 1

Docker容器内部：

 496: eth@if497: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default

    link/ether 02:42:ac:11:00:03 brd ff:ff:ff:ff:ff:ff link-netnsid 0

    inet 172.17.0.3/16 brd 172.17.255.255 scope global eth0

       valid_lft forever preferred_lft forever

使用evth-pair设备连接宿主机网络与容器网络