转自：https://www.cnblogs.com/horizonli/p/6093540.html
[root@controller ~]# modinfo 8021q filename: /lib/modules/3.10.0-229.14.1.el7.x86_64/kernel/net/8021q/8021q.ko version: 1.8 license: GPL alias: rtnl-link-vlan rhelversion: 7.1 srcversion: 2C3C3989B54002FAEC13FFD depends: mrp,garp intree: Y vermagic: 3.10.0-229.14.1.el7.x86_64 SMP mod_unload modversions signer: CentOS Linux kernel signing key sig_key: E9:9F:C4:37:BD:9C:BF:B4:F1:B1:DA:87:C1:57:FF:66:56:9B:EE:66 sig_hashalgo: sha256或者：[root@controller ~]# modinfo -F filename 8021q
/lib/modules/3.10.0-229.14.1.el7.x86_64/kernel/net/8021q/8021q.ko
或者：
[root@controller ~]# modprobe --first-time 8021q modprobe: ERROR: could not insert ‘8021q‘: Module already in kernel
2.如果没有加载802.1q模块怎么加载？
##加载8021q模块 [root@controller ~]# modprobe 8021q<br>##查看是否正常加载
[root@controller ~]# lsmod |grep 8021q
8021q 28808 0
garp 14384 1 8021q
mrp 18542 1 8021q
3.在父接口创建vlan子接口
3.1在父接口/etc/sysconfig/network-scripts/ifcfg-ethX 中设置
DEVICE=ethX TYPE=Ethernet BOOTPROTO=none ONBOOT=yes
3.2复制父接口并修改接口名称
cp /etc/sysconfig/network-scripts/ifcfg-ethX /etc/sysconfig/network-scripts/ifcfg-ethX.125 ## X后面的125为vlan号
3.3配置/etc/sysconfig/network-scripts/ifcfg-ethX.125
DEVICE=ethX.192 BOOTPROTO=none ONBOOT=yes IPADDR=192.168.1.1 PREFIX=24 NETWORK=192.168.1.0 VLAN=yes ##开启vlan，表明此子接口为vlan接口
4.重启网络
systemctl restart network
8021q module is loaded by default. If necessary, you can make sure that the module is loaded by issuing the following command as root:~]# modprobe --first-time 8021q modprobe: ERROR: could not insert ‘8021q‘: Module already in kernel To display information about the module, issue the following command: ~]$ modinfo 8021q See the modprobe(8) man page for more command options.
/etc/sysconfig/network-scripts/ifcfg-ethX, whereX is a unique number corresponding to a specific interface,as follows:DEVICE=ethX TYPE=Ethernet BOOTPROTO=none ONBOOT=yes
2.Configure the VLAN interface configuration in the /etc/sysconfig/network-scripts/directory. The configuration file name should be the parent interface plus a . character plus the VLAN ID number. For example, if the VLAN ID is 192, and the parent interface is eth0, then the configuration file name should be ifcfg-eth0.192:
DEVICE=ethX.192 BOOTPROTO=none ONBOOT=yes IPADDR=192.168.1.1 PREFIX=24 NETWORK=192.168.1.0 VLAN=yes
If there is a need to configure a second VLAN, with for example, VLAN ID 193, on the same interface, eth0, add a new file with the name eth0.193 with the VLAN configuration details.
3.Restart the networking service in order for the changes to take effect. As root issue the following command:
~]# systemctl restart network
7.4.2. Configure 802.1Q VLAN Tagging Using ip Commands
To create an 802.1Q VLAN interface on Ethernet interface eth0, with name VLAN8 and ID 8, issue a command as root as follows:
~]# ip link add link eth0 name eth0.8 type vlan id 8
To view the VLAN, issue the following command:
~]$ ip -d link show eth0.8 4: eth0.8@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT link/ether 52:54:00:ce:5f:6c brd ff:ff:ff:ff:ff:ff promiscuity 0 vlan protocol 802.1Q id 8 <REORDER_HDR>
0x and as an octal value if it has a leading 0. This means that in order to assign a VLAN ID with a decimal value of 22, you must not add any leading zeros.To remove the VLAN, issue a command as root as follows:
~]# ip link delete eth0.8
DEVICE=${SECONF_ETH}.${EXTERNAL_TENANT_NETWORK_VLAN_ID} BOOTPROTO=none ONBOOT=yes IPADDR=${SECOND_SUB_INTERFACE_IP} PREFIX=24 NETWORK=${SECOND_SUB_INTERFACE_NET} VLAN=yes
