I have Ubuntu 16 running on a Raspberry Pi 3 mobile platform, and if it's not connected to ethernet, and the wifi's out of range during boot, it takes about 15 minutes to boot, since it appears Ubuntu has a very long timeout while it waits to bring up eth0 or wlan0. I've tested this repeatedly, and when the boot takes forever, I find plugging in an ethernet cable magically makes boot completely instantly.

How do I disable this, so Ubuntu boots up quickly, regardless of network connectivity? I'm using Network Manager, which is excellent at re-establishing a wlan0 connection onces an recognized SSID is detected.

  • I am deleting my answer as I don't have an answer for you. I cannot duplicate your issue, and I don't want to keep guessing what your issue is. – Terrance Oct 11 '16 at 6:32
  • @Terrance, Actually, it looks like your solution works as well. Changing the conf in /etc/network/interfaces for eth0 from auto to manual also stopped the hanging during boot. – Cerin Oct 11 '16 at 13:59
  • I actually like your answer that you wrote. I didn't stop to think about having network ports listed in the interfaces file. That would also explain why I couldn't duplicate your issue, as I don't have those listed in my interfaces file. Nice find! =) – Terrance Oct 11 '16 at 14:01

Fire up your favorite text editor: /etc/systemd/system/network-online.targets.wants/networking.service

Find and edit this line with your meat fidgets: TimeoutStartSec=5min


| improve this answer | |

The sleep commands waiting for the network can be changed in the file

| improve this answer | |
  • That file doesn't exist on my system. – Cerin Oct 11 '16 at 14:00
  • Good to know, the ARM version of Ubuntu must be doing that elsewhere. – Katu Oct 12 '16 at 7:24

The problem is that eth0 was hardcoded in /etc/network/interfaces, so networking always tried to bring it up at boot.

Since I'm using Network Manager, I found the easiest solution was to remove all the eth0 entries from /etc/network/interfaces. This makes Network Manager auto-detect it and bring it up if present.

Edit: Even with the eth0 entry removed the /etc/network/interfaces, booting was still slow (even though it was faster than before). I found adding the entry back, but changing it from "auto" to "manual" made boot happen almost instantly.

| improve this answer | |
  • I have witnessed the slowness that you have mentioned in the servers I work on when they have an interface unplugged but enabled. And you are correct that they hang for a short time. So, good research that you have done. =) – Terrance Oct 11 '16 at 14:10

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.