Specifically for use on Proxmox (docs)

Create /etc/systemd/network/10-persistent-net.link:

[Match]
MACAddress=:01:23:45:67:89:ab
Type=ether

[Link]
Name=enlan0

Update any references in /etc/network/interfaces :

auto lo
iface lo inet loopback

# iface enx0123456789ab inet manual
iface en1an0 inet manual

auto vmbr0
iface vmbr0 inet static
        address 192.168.1.6/24
        gateway 192.168.1.1
        # bridge-ports enx0123456789ab
        bridge-ports enlan0
        bridge-stp off
        bridge-fd 0

source /etc/network/interfaces.d/*

DOUBLE-CHECK YOUR WORK. Make sure the names you created don’t conflict with existing naming conventions, and make sure you didn’t typo any of them.

Apply changes:

sudo update-initramfs -u -k all
sudo reboot

See also: