Docker网络（二）

CentOS 7: 对比docker启动前后，系统都有哪些变化

Docker启动之前

网络接口

[root@localhost ~]# ip addr show
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
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:b7:70:75 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.15/24 brd 192.168.0.255 scope global dynamic ens33
       valid_lft 28768sec preferred_lft 28768sec

路由表

[root@localhost ~]# ip route
default via 192.168.0.1 dev ens33 
192.168.0.0/24 dev ens33 proto kernel scope link src 192.168.0.15 

防火墙规则

iptables -L --line-numbers > 1.txt

Docker启动之后

网络接口

[root@localhost ~]#  ip addr show
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
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:b7:70:75 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.15/24 brd 192.168.0.255 scope global dynamic ens33
       valid_lft 27888sec preferred_lft 27888sec
3: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:c2:58:4e:a0 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

新增加了一个网桥docker0，子网172.17.0.1/16

路由表

[root@localhost ~]# ip route 
default via 192.168.0.1 dev ens33 
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 
192.168.0.0/24 dev ens33 proto kernel scope link src 192.168.0.15 

新增加了一条路由

防火墙规则

iptables -L --line-numbers > 2.txt

使用vimdiff 1.txt 2.txt,就可看出前后的规则变化了。详细说明请参考iptables相关的资料。

总之，Docker网络的初始化动作包括：创建docker0网桥、为docker0网桥新建子网以及路由、创建相应的iptbales规则等。