Centos7系统配置上的变化（三）为网络接口添加多IP

2023-01-25 14:20:02

原文 Centos7系统配置上的变化（三）为网络接口添加多IP

    • 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

      Centos7系统配置上的变化（三）为网络接口添加多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 enp0s3
      02.IP4.ADDRESS[1]:ip = 192.168.150.110/24, gw = 192.168.150.254
      03.[root@centos7 ~]#
      04.[root@centos7 ~]# ip addr show enp0s3 scope global
      05.2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
      06.link/ether 08:00:27:15:35:d2 brd ff:ff:ff:ff:ff:ff
      07.inet 192.168.150.110/24 brd 192.168.150.255 scope global enp0s3
      08.valid_lft forever preferred_lft forever
      09.[root@centos7 ~]#
      10.[root@centos7 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
      11.......
      12.IPADDR0=192.168.150.110
      13.PREFIX0=24
      14.GATEWAY0=192.168.150.254
      15.DNS1=192.168.150.254
      16.HWADDR=08:00:27:15:35:D2
      17.IPADDR1=192.168.150.111
      18.PREFIX1=24
      19.[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-eth0
      2.[root@centos7 ~]#
      3.[root@centos7 ~]# nmcli -t -f IP4.ADDRESS dev show enp0s3
      4.IP4.ADDRESS[1]:ip = 192.168.150.110/24, gw = 192.168.150.254
      5.[root@centos7 ~]#<br>[root@centos7 ~]# ip addr show enp0s3 scope global<br>2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000<br>    link/ether 08:00:27:15:35:d2 brd ff:ff:ff:ff:ff:ff<br>    inet 192.168.150.110/24 brd192.168.150.255 scope 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 network
      02.[root@centos7 ~]#
      03.[root@centos7 ~]# nmcli -t -f IP4.ADDRESS dev show enp0s3
      04.IP4.ADDRESS[1]:ip = 192.168.150.110/24, gw = 192.168.150.254
      05.IP4.ADDRESS[2]:ip = 192.168.150.111/24, gw = 192.168.150.254
      06.[root@centos7 ~]#
      07.[root@centos7 ~]# ip addr show enp0s3 scope global
      08.2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
      09.link/ether 08:00:27:15:35:d2 brd ff:ff:ff:ff:ff:ff
      10.inet 192.168.150.110/24 brd 192.168.150.255 scope global enp0s3
      11.valid_lft forever preferred_lft forever
      12.[root@centos7 ~]#
      13.[root@centos7 ~]#
      14.[root@centos7 ~]# ping 192.168.150.111
      15.PING 192.168.150.111 (192.168.150.111) 56(84) bytes of data.
      16.From 192.168.150.110 icmp_seq=1 Destination Host Unreachable
      17.From 192.168.150.110 icmp_seq=2 Destination Host Unreachable
      18.......
      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 enp0s3
      02.[root@centos7 ~]#
      03.[root@centos7 ~]#
      04.[root@centos7 ~]# nmcli -t -f IP4.ADDRESS dev show enp0s3
      05.IP4.ADDRESS[1]:ip = 192.168.150.110/24, gw = 192.168.150.254
      06.IP4.ADDRESS[2]:ip = 192.168.150.111/24, gw = 192.168.150.254
      07.[root@centos7 ~]#
      08.[root@centos7 ~]#
      09.[root@centos7 ~]# ip addr show enp0s3 scope global
      10.2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
      11.link/ether 08:00:27:15:35:d2 brd ff:ff:ff:ff:ff:ff
      12.inet 192.168.150.110/24 brd 192.168.150.255 scope global enp0s3
      13.valid_lft forever preferred_lft forever
      14.inet 192.168.150.111/24 brd 192.168.150.255 scope global secondary enp0s3
      15.valid_lft forever preferred_lft forever
      16.[root@centos7 ~]#
      17.[root@centos7 ~]#
      18.[root@centos7 ~]# ping 192.168.150.111
      19.PING 192.168.150.111 (192.168.150.111) 56(84) bytes of data.
      20.64 bytes from 192.168.150.111: icmp_seq=1 ttl=64 time=0.039 ms
      21.64 bytes from 192.168.150.111: icmp_seq=2 ttl=64 time=0.079 ms
      22.......
      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 add 192.168.150.113/24 dev enp0s3
      02.[root@centos7 ~]#
      03.[root@centos7 ~]#
      04.[root@centos7 ~]# nmcli -t -f IP4.ADDRESS dev show enp0s3
      05.IP4.ADDRESS[1]:ip = 192.168.150.110/24, gw = 192.168.150.254
      06.IP4.ADDRESS[2]:ip = 192.168.150.111/24, gw = 192.168.150.254
      07.IP4.ADDRESS[3]:ip = 192.168.150.112/24, gw = 192.168.150.254
      08.IP4.ADDRESS[4]:ip = 192.168.150.113/24, gw = 192.168.150.254
      09.[root@centos7 ~]#
      10.[root@centos7 ~]#
      11.[root@centos7 ~]# ip addr show enp0s3 scope global
      12.2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
      13.link/ether 08:00:27:15:35:d2 brd ff:ff:ff:ff:ff:ff
      14.inet 192.168.150.110/24 brd 192.168.150.255 scope global enp0s3
      15.valid_lft forever preferred_lft forever
      16.inet 192.168.150.111/24 brd 192.168.150.255 scope global secondary enp0s3
      17.valid_lft forever preferred_lft forever
      18.inet 192.168.150.112/24 brd 192.168.150.255 scope global secondary enp0s3
      19.valid_lft forever preferred_lft forever
      20.inet 192.168.150.113/24 scope global secondary enp0s3
      21.valid_lft forever preferred_lft forever
      22.[root@centos7 ~]#
      23.[root@centos7 ~]#
      24.[root@centos7 ~]# ping 192.168.150.113
      25.PING 192.168.150.113 (192.168.150.113) 56(84) bytes of data.
      26.64 bytes from 192.168.150.113: icmp_seq=1 ttl=64 time=0.098 ms
      27.64 bytes from 192.168.150.113: icmp_seq=2 ttl=64 time=0.255 ms
      28.......

      /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 del 192.168.150.113/24 dev enp0s3
      02.[root@centos7 ~]#
      03.[root@centos7 ~]#
      04.[root@centos7 ~]# nmcli -t -f IP4.ADDRESS dev show enp0s3
      05.IP4.ADDRESS[1]:ip = 192.168.150.110/24, gw = 192.168.150.254
      06.IP4.ADDRESS[2]:ip = 192.168.150.111/24, gw = 192.168.150.254
      07.IP4.ADDRESS[3]:ip = 192.168.150.112/24, gw = 192.168.150.254
      08.[root@centos7 ~]#
      09.[root@centos7 ~]#
      10.[root@centos7 ~]# ip addr show enp0s3 scope global
      11.2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
      12.link/ether 08:00:27:15:35:d2 brd ff:ff:ff:ff:ff:ff
      13.inet 192.168.150.110/24 brd 192.168.150.255 scope global enp0s3
      14.valid_lft forever preferred_lft forever
      15.inet 192.168.150.111/24 brd 192.168.150.255 scope global secondary enp0s3
      16.valid_lft forever preferred_lft forever
      17.inet 192.168.150.112/24 brd 192.168.150.255 scope global secondary enp0s3
      18.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-eth0
      02.TYPE=Ethernet
      03.BOOTPROTO=none
      04.DEFROUTE=yes
      05.IPV4_FAILURE_FATAL=no
      06.IPV6INIT=no
      07.IPV6_AUTOCONF=yes
      08.IPV6_DEFROUTE=yes
      09.IPV6_PEERDNS=yes
      10.IPV6_PEERROUTES=yes
      11.IPV6_FAILURE_FATAL=no
      12.NAME=eth0
      13.UUID=295e1841-0ff3-4db9-8800-4e25fc2944da
      14.ONBOOT=yes
      15.IPADDR0=192.168.150.110
      16.PREFIX0=24
      17.GATEWAY0=192.168.150.254
      18.DNS1=192.168.150.254
      19.HWADDR=08:00:27:15:35:D2
      20.#IPADDR1=192.168.150.111
      21.#PREFIX1=24
      22.#IPADDR2=192.168.150.112
      23.#PREFIX2=24
      24. 
      25.[root@centos7 ~]#
      26.[root@centos7 ~]#
      27.[root@centos7 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0:1
      28.TYPE=Ethernet
      29.BOOTPROTO=none
      30.DEFROUTE=yes
      31.IPV4_FAILURE_FATAL=no
      32.IPV6INIT=no
      33.IPV6_AUTOCONF=yes
      34.IPV6_DEFROUTE=yes
      35.IPV6_PEERDNS=yes
      36.IPV6_PEERROUTES=yes
      37.IPV6_FAILURE_FATAL=no
      38.NAME=eth0:1
      39.DEVICE=eth0:1
      40.UUID=295e1841-0ff3-4db9-8800-4e25fc2944da
      41.ONBOOT=yes
      42.IPADDR0=192.168.150.119
      43.PREFIX0=24
      44.GATEWAY0=192.168.150.254
      45.DNS1=192.168.150.254
      46.HWADDR=08:00:27:15:35:D2
      47.[root@centos7 ~]#
      48.[root@centos7 ~]# nmcli con reload
      49.[root@centos7 ~]# nmcli dev connect enp0s3
      50.[root@centos7 ~]#
      51.[root@centos7 ~]# nmcli -t -f IP4.ADDRESS dev show enp0s3
      52.IP4.ADDRESS[1]:ip = 192.168.150.110/24, gw = 192.168.150.254
      53.[root@centos7 ~]#
      54.[root@centos7 ~]#
      55.[root@centos7 ~]# ip addr show enp0s3 scope global
      56.2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
      57.link/ether 08:00:27:15:35:d2 brd ff:ff:ff:ff:ff:ff
      58.inet 192.168.150.110/24 brd 192.168.150.255 scope global eth0:1
      59.valid_lft forever preferred_lft forever
      60.[root@centos7 ~]#

      可以看到ifcfg-eth0:1里的新IP确实没有生效。
      五、总结

      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

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