Use of Predictable Network Interface Names with alternate kernels

You need to distinguish between 3 things:

• Predictable interfaces names
• biosdevname
• 70-persistent.rules udev rule

You either choose to use one of these solution but you don't use 2 or 3 at the same time. (In fact, you can but one will take precedence and mask the other(s))

A good introduction to the current situation is the post on the ubuntu dev mailing list

Predictable interface names

Predictable interface names is a udevd thing since v197 generated in /lib/udev/rules.d/80-net-setup-link.rules

systemd use by default the new predictable interface name. However, unless upstream systemd, in Ubuntu, you have to opt-in by using net.ifnames=1

It does not matter the kernel version you are running. But you need to use the kernel command line to configure it by changing grub configuration /etc/default/grub, like:

GRUB_CMDLINE_LINUX_DEFAULT="net.ifnames=1"

and run

sudo update-grub

In 14.04 or 14.10, without systemd, it should be enough to remove 70-persitent-net.rules, as described below in the note.

Biosdevname

biosdevname is a dell attempt to solve a similar problem than predictable interface name in systemd. It is the default on ubuntu server. You can have it by installing the package biosdevname

sudo apt-get install biosdevname

Note

You can disable it by using kernel command line in grub config:

GRUB_CMDLINE_LINUX_DEFAULT="biosdevname=0"

and run

sudo update-grub

or simply uninstall the package.

sudo apt-get purge biosdevname
sudo update-initramfs -u

udev rules

This is the default on Ubuntu desktop. The udev rule /lib/udev/rules.d/75-persistent-net-generator.rules creates during the first boot a custom rules /etc/udev/rules.d/70-persistent-net.rules with MAC address of your interface to get persistent name for your interface.

Note

If you are already using udev rules, you need to remove /etc/udev/rules.d/70-persistent-net.rules and to avoid it being regenerated at each boot you need to run

sudo ln -s /dev/null /etc/udev/rules.d/75-persistent-net-generator.rules

After that, if you use systemd, then you need to opt-in for predictable interface name, as describe above.

1. In Ubuntu Server 16.04LTS all I did was run:

   ln -s /dev/null /etc/udev/rules.d/80-net-setup-link.rules
   

2. Then create the file using

   sudo vi /etc/systemd/network/10-internet.link
   

   and add the following

   [Match]
   Path=pci-0000:(your device mac address)
   
   [Link]
   Name=eth0 (or whatever you want to name it)
   

   :wq to save the file

3. then reboot and adjust your /etc/network/interfaces file.. then reboot again

Hope this helps someone