yahoo-eng-team team mailing list archive

Thread
Date

[Bug 1863773] [NEW] cloud-init network fails if ipv6 is disabled

To: yahoo-eng-team@xxxxxxxxxxxxxxxxxxx
From: Bas Zoetekouw <bas@xxxxxxxxxx>
Date: Tue, 18 Feb 2020 15:37:14 -0000
Reply-to: Bug 1863773 <1863773@xxxxxxxxxxxxxxxxxx>
Sender: bounces@xxxxxxxxxxxxx

Public bug reported:

I'm using cloud-init on a Debian machien in AWS.

On these machiesn, ipv6 is disabled by setting
/proc/sys/net/ipv6/conf/all/disable_ipv6 to 1. This causes the network
to fail:

bas@machine:/etc/network$ sudo ifup ens5
Internet Systems Consortium DHCP Client 4.4.1
Copyright 2004-2018 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/ens5/02:45:ca:0d:93:76
Sending on LPF/ens5/02:45:ca:0d:93:76
Sending on Socket/fallback
DHCPREQUEST for 10.0.16.20 on ens5 to 255.255.255.255 port 67
DHCPACK of 10.0.16.20 from 10.0.16.1
RTNETLINK answers: File exists
bound to 10.0.16.20 -- renewal in 1796 seconds.

Could not get a link-local address
run-parts: /etc/network/if-pre-up.d/cloud_inet6 exited with return code 1
ifup: failed to bring up ens5

Even worse, on boot the machines do get a proper ipv4 address, but (apparently because setting up the network fails), the dhcp (v4) daemon is stopped, and the machines "mysteriously" drop off the net after the lease ends.

1. AWS with official Debian buster images (https://wiki.debian.org/Cloud/AmazonEC2Image/Buster)
2.

bas@machine:~$ cat /etc/network/interfaces
# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d

# Cloud images dynamically generate config fragments for newly
# attached interfaces. See /etc/udev/rules.d/75-cloud-ifupdown.rules
# and /etc/network/cloud-ifupdown-helper. Dynamically generated
# configuration fragments are stored in /run:
source-directory /run/network/interfaces.d

bas@machine:~$ cat /run/network/interfaces.d/ens5
auto ens5
allow-hotplug ens5

iface ens5 inet dhcp

iface ens5 inet6 manual
try_dhcp 1

** Affects: cloud-init
Importance: Undecided
Status: New

** Attachment added: "cloud-init.tar.gz"
https://bugs.launchpad.net/bugs/1863773/+attachment/5329329/+files/cloud-init.tar.gz

--
You received this bug notification because you are a member of Yahoo!
Engineering Team, which is subscribed to cloud-init.
https://bugs.launchpad.net/bugs/1863773

Title:
cloud-init network fails if ipv6 is disabled

Status in cloud-init:
New

Bug description:
I'm using cloud-init on a Debian machien in AWS.

On these machiesn, ipv6 is disabled by setting
/proc/sys/net/ipv6/conf/all/disable_ipv6 to 1. This causes the
network to fail: