CentOS 7 网卡子接口的创建

OS:CentOS 7

在linux上创建vlan需要加载802.1q模块：

1.检测OS是否已经加载802.1q模块

[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
##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

================================================

CONFIGURE 802.1Q VLAN TAGGING USING THE COMMAND LINE

In Red Hat Enterprise Linux 7, the 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.

7.4.1. Setting Up 802.1Q VLAN Tagging Using ifcfg Files

Configure the parent interface in /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
```
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.
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>

Note that the ip utility interprets the VLAN ID as a hexadecimal value if it is preceded by 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

================

总结：修改父接口的BOOTPROTO=manual

复制父接口，

清空内容

注入下面的内容：

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