docker 默认有4种网络模式，详细可查看我曾经写的 "docker几种网络模式"

docker run 新建并启动容器时，不指定网络，默认是使用桥接模式，容器内部IP是通过DHCP获取，容器网桥名为docker0，docker容器重启后，其容器IP会变化。有没有办法来固定容器内的IP呢？答案是肯定的。可以使用脚本或工具来固定容器内部IP。

一、如何查看容器内部IP？：

方法一：

通过docker inspect查看容器的详细信息来查看，可以使用grep来匹配查询

[root@localhost ~]# docker inspect centos7 | grep -aiE ipaddress
            "SecondaryIPAddresses": null,
            "IPAddress": "172.17.0.2",
                    "IPAddress": "172.17.0.2",
[root@localhost ~]# docker inspect centos7 | grep -aiE ipaddress | tail -1
                    "IPAddress": "172.17.0.2",

[root@localhost ~]# docker inspect centos7 | grep -aiE ipaddress | tail -1 | grep -aiowE "([0-9]{1,3}\.)([0-9]{1,3}\.)([0-9]{1,3}\.)([0-9]{1,3})"  
172.17.0.2
[root@localhost ~]# 

[root@localhost ~]# docker inspect centos7 | grep -aiE ipaddress | tail -1 | grep -aiowE "([0-9]{1,3}\.){3}[0-9]{1,3}"                           
172.17.0.2
[root@localhost ~]# 

方法二：

通过docker exec  来查看

[root@localhost ~]# docker exec centos7 ifconfig 
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.17.0.2  netmask 255.255.0.0  broadcast 172.17.255.255
        ether 02:42:ac:11:00:02  txqueuelen 0  (Ethernet)
        RX packets 15026  bytes 35185160 (33.5 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 9009  bytes 503286 (491.4 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[root@localhost ~]# 

方法三

docker    exec登录容器内查看

[root@localhost ~]# docker exec -it centos7 /bin/bash
[root@b7f8b1907403 ansible]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.17.0.2  netmask 255.255.0.0  broadcast 172.17.255.255
        ether 02:42:ac:11:00:02  txqueuelen 0  (Ethernet)
        RX packets 15026  bytes 35185160 (33.5 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 9009  bytes 503286 (491.4 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[root@b7f8b1907403 ansible]# 

二、固定容器内部IP

1、使用pipework工具

[root@localhost src]# ls
debug  default.conf  harbor  jforum-2.5.0.war  kernels  nginx.conf  pipework
[root@localhost src]# mv pipework  /usr/local/bin
[root@localhost src]# pipework -h
-bash: /usr/local/bin/pipework: 权限不够
[root@localhost src]# chmod +x /usr/local/bin/pipework 
[root@localhost src]# pipework  -h
Syntax:
pipework <hostinterface> [-i containerinterface] [-l localinterfacename] [-a addressfamily] <guest> <ipaddr>/<subnet>[@default_gateway] [macaddr][@vlan]
pipework <hostinterface> [-i containerinterface] [-l localinterfacename] <guest> dhcp [macaddr][@vlan]
pipework mac:<hostinterface_macaddress> [-i containerinterface] [-l localinterfacename] [-a addressfamily] <guest> <ipaddr>/<subnet>[@default_gateway] [macaddr][@vlan]
pipework mac:<hostinterface_macaddress> [-i containerinterface] [-l localinterfacename] <guest> dhcp [macaddr][@vlan]
pipework route <guest> <route_command>
pipework rule <guest> <rule_command>
pipework tc <guest> <tc_command>
pipework --wait [-i containerinterface]
[root@localhost src]# 

把容器内部IP固定为：172.17.0.2

[root@localhost src]# pipework  docker0 centos7 172.17.0.2/[email protected]
[root@localhost src]# 

docker0为网桥名。容器内网桥名。172.17.0.1为容器的网关。

重启容器确认IP变化

[root@localhost src]# docker restart  centos7
centos7

[root@localhost src]# docker inspect centos7 | grep -aiE ipaddress | tail -1
                    "IPAddress": "172.17.0.2",
[root@localhost src]# 

[root@localhost src]# ping 172.17.0.2
PING 172.17.0.2 (172.17.0.2) 56(84) bytes of data.
64 bytes from 172.17.0.2: icmp_seq=1 ttl=64 time=0.114 ms
64 bytes from 172.17.0.2: icmp_seq=2 ttl=64 time=0.192 ms
^C
--- 172.17.0.2 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1003ms
rtt min/avg/max/mdev = 0.114/0.153/0.192/0.039 ms
[root@localhost src]#

发现，多次重启容器，IP始终为172.17.0.2不再变化。