Centos7系统配置上的变化（三）为网络接口添加多IP

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

  

  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