At present, various OS operating system versions have been upgraded frantically, and the operating system settings that have changed with it have also been greatly changed. The latest version of CENTOS has been
It is 8.x. However, compared with the previous version of centos 7.6, some of the configuration related to the operating system has changed a lot, for example: static IP and configuration parameters
NM_CONTROLLED, when the parameters are not changed in the network configuration file, even if its IP configuration uses static IP, it will not work.
--ifcfg-ens34 configuration
[root@centos76mysqlpri network-scripts]# cat ifcfg-ens34
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=static #Static IP has been declared here
DEFROUTE = yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE = yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=ens34
UUID=af87d788-f524-4095-81c9-367eba488f9a
DEVICE=ens34
ONBOOT=yes
IPADDR=192.168.192.201
PREFIX=24
GATEWAY=192.168.192.1
IPV6_PRIVACY=no
[root@centos76mysqlpri network-scripts]#
--Ifcfg-ens34 IP address missing after startup is not expected
[root@centos76mysqlpri network-scripts]# ifup ens34
[root@centos76mysqlpri network-scripts]# ifconfig -a
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.248.129 netmask 255.255.255.0 broadcast 192.168.248.255
inet6 fe80::7391:3e5e:cead:f642 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:26:76:0c txqueuelen 1000 (Ethernet)
RX packets 13523 bytes 17404331 (16.5 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 5554 bytes 343077 (335.0 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ens34: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.192.128 netmask 255.255.255.0 broadcast 192.168.192.255
inet6 fe80::2162:583:8ee:d0be prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:26:76:16 txqueuelen 1000 (Ethernet)
RX packets 63 bytes 7008 (6.8 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 138 bytes 20565 (20.0 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
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 224 bytes 18384 (17.9 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 224 bytes 18384 (17.9 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255
ether 52:54:00:2f:86:09 txqueuelen 1000 (Ethernet)
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
virbr0-nic: flags=4098<BROADCAST,MULTICAST> mtu 1500
ether 52:54:00:2f:86:09 txqueuelen 1000 (Ethernet)
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@centos76mysqlpri network-scripts]#
At this point, it feels a bit inexplicable! The query is: centos7.6 uses the NM_CONTROLLED parameter to control whether it is managed by the network manager.
--Modify the configuration of ifcfg-ens34
[root@centos76mysqlpri network-scripts]# cat ifcfg-ens34
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=static
DEFROUTE = yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE = yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=ens34
UUID=af87d788-f524-4095-81c9-367eba488f9a
DEVICE=ens34
ONBOOT=yes
NM_CONTROLLED=no
IPADDR=192.168.192.201
PREFIX=24
GATEWAY=192.168.192.1
IPV6_PRIVACY=no
[root@centos76mysqlpri network-scripts]#
--ifcfg-ens34 after the network card restarts
[root@centos76mysqlpri network-scripts]# ifup ens34
[root@centos76mysqlpri network-scripts]# ifconfig -a
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.248.129 netmask 255.255.255.0 broadcast 192.168.248.255
inet6 fe80::7391:3e5e:cead:f642 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:26:76:0c txqueuelen 1000 (Ethernet)
RX packets 13523 bytes 17404331 (16.5 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 5554 bytes 343077 (335.0 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ens34: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.192.201 netmask 255.255.255.0 broadcast 192.168.192.255
inet6 fe80::20c:29ff:fe26:7616 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:26:76:16 txqueuelen 1000 (Ethernet)
RX packets 81 bytes 8664 (8.4 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 167 bytes 24573 (23.9 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
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 224 bytes 18384 (17.9 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 224 bytes 18384 (17.9 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255
ether 52:54:00:2f:86:09 txqueuelen 1000 (Ethernet)
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
virbr0-nic: flags=4098<BROADCAST,MULTICAST> mtu 1500
ether 52:54:00:2f:86:09 txqueuelen 1000 (Ethernet)
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@centos76mysqlpri network-scripts]#