原文 Centos7系统配置上的变化（三）为网络接口添加多IP
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实验的方法有 nmtui, 编辑ifcfg-*文件，ip addr 指令，子连接配置文件。
一、nmtui手工添加IP
看一下当前网络设备的IP，为了精简指令输出，指令就要复杂一些了：
01.[root@centos7~]# nmcli -t -f IP4.ADDRESS dev show enp0s302.IP4.ADDRESS[1]:ip =192.168.150.110/24, gw =192.168.150.25403.[root@centos7~]#04.[root@centos7~]# ip addr show enp0s3 scope global05.2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu1500qdisc pfifo_fast state UP qlen100006.link/ether08:00:27:15:35:d2 brd ff:ff:ff:ff:ff:ff07.inet192.168.150.110/24brd192.168.150.255scope global enp0s308.valid_lft forever preferred_lft forever09.[root@centos7~]#10.[root@centos7~]# cat /etc/sysconfig/network-scripts/ifcfg-eth011.......12.IPADDR0=192.168.150.11013.PREFIX0=2414.GATEWAY0=192.168.150.25415.DNS1=192.168.150.25416.HWADDR=08:00:27:15:35:D217.IPADDR1=192.168.150.11118.PREFIX1=2419.[root@centos7~]#新IP已经被加入到ifcfg-eth0中，原始地址的关键字是 IPADDR0、PREFIX0，新地址的关键字是 IPADDR1、PREFIX1 。
1.[root@centos7~]# nmcli con load /etc/sysconfig/network-scripts/ifcfg-eth02.[root@centos7~]#3.[root@centos7~]# nmcli -t -f IP4.ADDRESS dev show enp0s34.IP4.ADDRESS[1]:ip =192.168.150.110/24, gw =192.168.150.2545.[root@centos7~]#<br>[root@centos7~]# ip addr show enp0s3 scope global<br>2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu1500qdisc pfifo_fast state UP qlen1000<br> link/ether08:00:27:15:35:d2 brd ff:ff:ff:ff:ff:ff<br> inet192.168.150.110/24brd192.168.150.255scope global enp0s3<br> valid_lft forever preferred_lft forever<br>[root@centos7~]#load connection 后，NetworkManager 也没有知晓新增IP，新增IP也没有出现在 ip addr show 中。
01.[root@centos7~]# systemctl restart network02.[root@centos7~]#03.[root@centos7~]# nmcli -t -f IP4.ADDRESS dev show enp0s304.IP4.ADDRESS[1]:ip =192.168.150.110/24, gw =192.168.150.25405.IP4.ADDRESS[2]:ip =192.168.150.111/24, gw =192.168.150.25406.[root@centos7~]#07.[root@centos7~]# ip addr show enp0s3 scope global08.2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu1500qdisc pfifo_fast state UP qlen100009.link/ether08:00:27:15:35:d2 brd ff:ff:ff:ff:ff:ff10.inet192.168.150.110/24brd192.168.150.255scope global enp0s311.valid_lft forever preferred_lft forever12.[root@centos7~]#13.[root@centos7~]#14.[root@centos7~]# ping192.168.150.11115.PING192.168.150.111(192.168.150.111)56(84) bytes of data.16.From192.168.150.110icmp_seq=1Destination Host Unreachable17.From192.168.150.110icmp_seq=2Destination Host Unreachable18.......19.[root@centos7~]#重启network服务后，NetworkManager 知晓新增IP了，但新增IP还是没有生效。
01.[root@centos7~]# nmcli dev connect enp0s302.[root@centos7~]#03.[root@centos7~]#04.[root@centos7~]# nmcli -t -f IP4.ADDRESS dev show enp0s305.IP4.ADDRESS[1]:ip =192.168.150.110/24, gw =192.168.150.25406.IP4.ADDRESS[2]:ip =192.168.150.111/24, gw =192.168.150.25407.[root@centos7~]#08.[root@centos7~]#09.[root@centos7~]# ip addr show enp0s3 scope global10.2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu1500qdisc pfifo_fast state UP qlen100011.link/ether08:00:27:15:35:d2 brd ff:ff:ff:ff:ff:ff12.inet192.168.150.110/24brd192.168.150.255scope global enp0s313.valid_lft forever preferred_lft forever14.inet192.168.150.111/24brd192.168.150.255scope global secondary enp0s315.valid_lft forever preferred_lft forever16.[root@centos7~]#17.[root@centos7~]#18.[root@centos7~]# ping192.168.150.11119.PING192.168.150.111(192.168.150.111)56(84) bytes of data.20.64bytes from192.168.150.111: icmp_seq=1ttl=64time=0.039ms21.64bytes from192.168.150.111: icmp_seq=2ttl=64time=0.079ms22.......23.[root@centos7~]#重新连接设备 enp0s3，新IP生效了。注意：不需要先断开设备（nmcli dev disconnect enp0s3），断开设备的话ssh立刻断线。重新连接设备的过程中，ssh是不会断线的。
nmtui添加IP后，需要： nmcli con load /etc/sysconfig/network-scripts/ifcfg-eth0 nmcli dev connect enp0s3
二、手工添加IP到ifcfg-eth0
在ifcfg-eth0配置文件中手工添加如下两行： IPADDR2=192.168.150.112 PREFIX2=24
先执行 nmcli con load /etc/sysconfig/network-scripts/ifcfg-eth0 后，在nmtui中可以看到新增IP。（也可以简单的用 nmcli con reload ，reload 和 load的区别自己脑补一下吧。） 再执行 nmcli dev connect enp0s3 后，IP 192.168.150.112 才生效的。手工添加IP到ifcfg-eth0后，需要： nmcli con load /etc/sysconfig/network-scripts/ifcfg-eth0 或 nmcli con reload nmcli dev connect enp0s3
三、用ip addr add指令添加/删除IP，即刻生效，重启不保留。
在线添加IP：01.[root@centos7~]# ip addr add192.168.150.113/24dev enp0s302.[root@centos7~]#03.[root@centos7~]#04.[root@centos7~]# nmcli -t -f IP4.ADDRESS dev show enp0s305.IP4.ADDRESS[1]:ip =192.168.150.110/24, gw =192.168.150.25406.IP4.ADDRESS[2]:ip =192.168.150.111/24, gw =192.168.150.25407.IP4.ADDRESS[3]:ip =192.168.150.112/24, gw =192.168.150.25408.IP4.ADDRESS[4]:ip =192.168.150.113/24, gw =192.168.150.25409.[root@centos7~]#10.[root@centos7~]#11.[root@centos7~]# ip addr show enp0s3 scope global12.2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu1500qdisc pfifo_fast state UP qlen100013.link/ether08:00:27:15:35:d2 brd ff:ff:ff:ff:ff:ff14.inet192.168.150.110/24brd192.168.150.255scope global enp0s315.valid_lft forever preferred_lft forever16.inet192.168.150.111/24brd192.168.150.255scope global secondary enp0s317.valid_lft forever preferred_lft forever18.inet192.168.150.112/24brd192.168.150.255scope global secondary enp0s319.valid_lft forever preferred_lft forever20.inet192.168.150.113/24scope global secondary enp0s321.valid_lft forever preferred_lft forever22.[root@centos7~]#23.[root@centos7~]#24.[root@centos7~]# ping192.168.150.11325.PING192.168.150.113(192.168.150.113)56(84) bytes of data.26.64bytes from192.168.150.113: icmp_seq=1ttl=64time=0.098ms27.64bytes from192.168.150.113: icmp_seq=2ttl=64time=0.255ms28......./etc/sysconfig/network-scripts/ifcfg-eth0 配置文件里并没有192.168.150.113，所以重启后该IP不会保留。
在线删除IP：01.[root@centos7~]# ip addr del192.168.150.113/24dev enp0s302.[root@centos7~]#03.[root@centos7~]#04.[root@centos7~]# nmcli -t -f IP4.ADDRESS dev show enp0s305.IP4.ADDRESS[1]:ip =192.168.150.110/24, gw =192.168.150.25406.IP4.ADDRESS[2]:ip =192.168.150.111/24, gw =192.168.150.25407.IP4.ADDRESS[3]:ip =192.168.150.112/24, gw =192.168.150.25408.[root@centos7~]#09.[root@centos7~]#10.[root@centos7~]# ip addr show enp0s3 scope global11.2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu1500qdisc pfifo_fast state UP qlen100012.link/ether08:00:27:15:35:d2 brd ff:ff:ff:ff:ff:ff13.inet192.168.150.110/24brd192.168.150.255scope global enp0s314.valid_lft forever preferred_lft forever15.inet192.168.150.111/24brd192.168.150.255scope global secondary enp0s316.valid_lft forever preferred_lft forever17.inet192.168.150.112/24brd192.168.150.255scope global secondary enp0s318.valid_lft forever preferred_lft forever四、使用子连接配置文件 ifcfg-*:n
子连接配置文件是 Centos6 常用的方法，即：如果当前网卡配置文件为 ifcfg-eth0，则子连接配置文件可以为 ifcfg-eth0:1，并且文件中需要写明 DEVICE=eth0:1 ， IPADDR=<新IP地址> 。 我们试试在Centos7 中是否也支持。理论上应该是不支持的，因为在Centos7的网络连接配置文件（即 ifcfg-*）中，DEVICE关键字已经具有了新的定义，即我们上篇说的“设备”。参考上篇 http://www.cnblogs.com/panblack/p/Centos7-WhatsNew-02-networking.html首先注释掉ifcfg-eth0中的其他地址，复制 ifcfg-eth0 为 ifcfg-eth0:1，编辑ifcfg-eth0:1， DEVICE 设为eth0:1 ，IP设为 192.168.150.119 ，然后 nmcli con reload ， nmcli dev con enp0s3
01.[root@centos7~]# cat /etc/sysconfig/network-scripts/ifcfg-eth002.TYPE=Ethernet03.BOOTPROTO=none04.DEFROUTE=yes05.IPV4_FAILURE_FATAL=no06.IPV6INIT=no07.IPV6_AUTOCONF=yes08.IPV6_DEFROUTE=yes09.IPV6_PEERDNS=yes10.IPV6_PEERROUTES=yes11.IPV6_FAILURE_FATAL=no12.NAME=eth013.UUID=295e1841-0ff3-4db9-8800-4e25fc2944da14.ONBOOT=yes15.IPADDR0=192.168.150.11016.PREFIX0=2417.GATEWAY0=192.168.150.25418.DNS1=192.168.150.25419.HWADDR=08:00:27:15:35:D220.#IPADDR1=192.168.150.11121.#PREFIX1=2422.#IPADDR2=192.168.150.11223.#PREFIX2=2424.25.[root@centos7~]#26.[root@centos7~]#27.[root@centos7~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0:128.TYPE=Ethernet29.BOOTPROTO=none30.DEFROUTE=yes31.IPV4_FAILURE_FATAL=no32.IPV6INIT=no33.IPV6_AUTOCONF=yes34.IPV6_DEFROUTE=yes35.IPV6_PEERDNS=yes36.IPV6_PEERROUTES=yes37.IPV6_FAILURE_FATAL=no38.NAME=eth0:139.DEVICE=eth0:140.UUID=295e1841-0ff3-4db9-8800-4e25fc2944da41.ONBOOT=yes42.IPADDR0=192.168.150.11943.PREFIX0=2444.GATEWAY0=192.168.150.25445.DNS1=192.168.150.25446.HWADDR=08:00:27:15:35:D247.[root@centos7~]#48.[root@centos7~]# nmcli con reload49.[root@centos7~]# nmcli dev connect enp0s350.[root@centos7~]#51.[root@centos7~]# nmcli -t -f IP4.ADDRESS dev show enp0s352.IP4.ADDRESS[1]:ip =192.168.150.110/24, gw =192.168.150.25453.[root@centos7~]#54.[root@centos7~]#55.[root@centos7~]# ip addr show enp0s3 scope global56.2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu1500qdisc pfifo_fast state UP qlen100057.link/ether08:00:27:15:35:d2 brd ff:ff:ff:ff:ff:ff58.inet192.168.150.110/24brd192.168.150.255scope global eth0:159.valid_lft forever preferred_lft forever60.[root@centos7~]#可以看到ifcfg-eth0:1里的新IP确实没有生效。
ip addr show 中显示的IP才是有效的。 ip addr add 能在线添加IP，立即生效，但重启即丢。 ip addr del 能在线删除IP，立即生效，但重启即丢。 子连接(ifcfg-*:n)已经无效了。 nmtui和编辑ifcfg-eth0 文件效果基本相同，都不能立即生效，必须 load 连接再重新connect网络设备，即： nmcli con load /etc/sysconfig/network-scripts/ifcfg-eth0 或 nmcli reload nmcli dev connect enp0s3
五、总结
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