redhat 7 eth 网卡命名规则

其实大家都知道传统的命名方式有问题,这个问题不仅仅是在linux上有,在VMware这种上也有,之前经常看着搞系统的人给ESXI主机加网卡,加完了就各种不同了,原有都是VINC0之类,加完网卡后就各种混乱了,导致原有的规划和实际不符合,虽然通过重组或重新排序可以解决,但是在实际生产环境是不方便操作的。

redhat也意识到这个问题,在redhat 7里面就重新设定了命令规则,命令规则和网卡插槽位置相关这种是比较科学比较贴近人类的。在过去运维中,系统的网卡还要跟实际网卡插槽或者板载网卡需要维护一个对应关系表,如果设备硬件完全一致还可以记下来,如果设备硬件有太多型号,每次都要去查表才知道系统里面的eth0对应外面那个接口。

这个功能在路由器上其实一直都是实现的很好,是几槽几卡的什么类型接口,配置就可以看出来,例如interface TenG 5/1/1就知道是五槽第一块卡的第一个接口,万兆接口。

以下来自红帽官网:

     Red Hat Enterprise Linux 7 provides methods for consistent and predictable network device naming for network interfaces. These features change the name of network interfaces on a system in order to make locating and differentiating the interfaces easier.

    Traditionally, network interfaces in Linux are enumerated as eth[0123…], but these names do not necessarily correspond to actual labels on the chassis. Modern server platforms with multiple network adapters can encounter non-deterministic and counter-intuitive naming of these interfaces. This affects both network adapters embedded on the motherboard (Lan-on-Motherboard, or LOM) and add-in (single and multiport) adapters.

    In Red Hat Enterprise Linux 7, udev supports a number of different naming schemes. The default is to assign fixed names based on firmware, topology, and location information. This has the advantage that the names are fully automatic, fully predictable, that they stay fixed even if hardware is added or removed (no re-enumeration takes place), and that broken hardware can be replaced seamlessly. The disadvantage is that they are sometimes harder to read than the eth0 or wlan0 names traditionally used. For example: enp5s0.

以下是新的命名规则

By default, systemd will name interfaces using the following policy to apply the supported naming schemes:

  • Scheme 1: Names incorporating Firmware or BIOS provided index numbers for on-board devices (example: eno1), are applied if that information from the firmware or BIOS is applicable and available, else falling back to scheme 2.

  • Scheme 2: Names incorporating Firmware or BIOS provided PCI Express hotplug slot index numbers (example: ens1) are applied if that information from the firmware or BIOS is applicable and available, else falling back to scheme 3.

  • Scheme 3: Names incorporating physical location of the connector of the hardware (example: enp2s0), are applied if applicable, else falling directly back to scheme 5 in all other cases.

  • Scheme 4: Names incorporating interface's MAC address (example: enx78e7d1ea46da), is not used by default, but is available if the user chooses.

  • Scheme 5: The traditional unpredictable kernel naming scheme, is used if all other methods fail (example: eth0).

This policy, the procedure outlined above, is the default. If the system has biosdevname enabled, it will be used. Note that enabling biosdevname requires passing biosdevname=1 as a command-line parameter except in the case of a Dell system, where biosdevname will be used by default as long as it is installed. If the user has added udev rules which change the name of the kernel devices, those rules will take precedence.

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