Why I'm giving message `A start job is running for raise network interfaces` at boot after disabling predictable network interfaces names?

Question

I disabled predictable network interfaces names by changing GRUB_CMDLINE_LINUX line in /etc/default/grub from:

GRUB_CMDLINE_LINUX="pci=nomsi"

to:

GRUB_CMDLINE_LINUX="pci=nomsi net.ifnames=0"

on a fresh installation of Debian GNU/Linux testing system with installed proprietary NVIDIA drivers. I did it because my external USB Wi-Fi card didn't work with systemd interfaces names.

After disabling predictable network interfaces names I'm giving following message at boot:

A start job is running for raise network interfaces (2 minutes of 5 mins 1 sec)

and system boots long.

My /etc/network/intefaces file:

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

Why am I giving this message at boot? How can I avoid long booting of my system?

Answer 1

Solved by changing file /etc/network/interfaces.d/setup from:

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp

to:

auto lo
iface lo inet loopback

allow-hotplug eth0
iface eth0 inet dhcp

Answer 2

Disable the service that waits to start the network interfaces.

systemctl disable NetworkManager-wait-online.service

And to enable:

systemctl enable NetworkManager-wait-online.service

Alternatively you can reduce the amount of time that it waits to start the job.

vim /etc/systemd/system/network-online.target.wants/networking.service 

TimeoutStartSec=5min ##Change parameter, should be at the end of the page.