configuring DHCPv6 wipes out any nameservers set while configuring IPv4

Bug #1768632 reported by Arne Lovius
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
subiquity
Triaged
Medium
Unassigned
debian-installer (Ubuntu)
Invalid
Undecided
Unassigned

Bug Description

installing from 18.04 Server ISO
Selected static IPv4 address, Gateway and DNS

retyped from installer output

writing to file /tmp/tmp9711pfi_state/network_config with network config: network:
  ethernets:
    eth0:
      addresses:
      - 192.168.53.34/24
      dhcp6: tru
      gateway4: 192.168.53.251
      nameservers: {}
      iotional: true
  version: 2

This then causes the install to fail.

Using DHCP does not have this problem

Arne Lovius (automaton)
description: updated
Revision history for this message
Ubuntu Foundations Team Bug Bot (crichton) wrote :

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1768632/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

tags: added: bot-comment
Revision history for this message
Arne Lovius (automaton) wrote :

This relates to the Ubuntu 18.04 installer, I do not know what "package" this would relate to

affects: ubuntu → debian-installer (Ubuntu)
Changed in debian-installer (Ubuntu):
assignee: nobody → Dimitri John Ledkov (xnox)
Revision history for this message
Dimitri John Ledkov (xnox) wrote :

Based on your output, I believe you are using the new Ubuntu Server installer.

I have attempted to reproduce the issue at hand, and I have managed to complete the installation with dhcpv6 + static ipv4 connectivity with DNS server propagating correctly to the installed system. The end networking info generated was:

# This file is generated from information provided by
# the datasource. Changes to it will not persist across an instance.
# To disable cloud-init's network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
network:
    ethernets:
        ens3:
            addresses:
            - 192.168.122.7/24
            dhcp6: true
            gateway4: 192.168.122.1
            nameservers:
                addresses:
                - 192.168.122.1
                search: []
            optional: true
    version: 2

Which is what I would expect, after filling out static network configuration (subnet, ip, gateway, nameserver).

Please provide more detailed instruction on how to reproduce the issue? Or maybe inspect the system using additional tty's? And provide more detailed steps and screenshots / photos?

Changed in debian-installer (Ubuntu):
status: New → Incomplete
Changed in subiquity:
status: New → Incomplete
Changed in debian-installer (Ubuntu):
assignee: Dimitri John Ledkov (xnox) → nobody
Revision history for this message
Arne Lovius (automaton) wrote :

The environment is Hyper-V 2012r2, screenshots as attached

Revision history for this message
Arne Lovius (automaton) wrote :
Revision history for this message
Arne Lovius (automaton) wrote :
Revision history for this message
Arne Lovius (automaton) wrote :
Revision history for this message
Michael Hudson-Doyle (mwhudson) wrote :

"This then causes the install to fail." what do you mean by this? The screenshots you've posted look fine to me.

Revision history for this message
Arne Lovius (automaton) wrote :

As the IP stack is up, just not DNS, I was able to use another TTY and FTP the contents of the attached .zip to a local FTP server

If there are other files that would be more useful, please let me know.

From the type of issue, I don't see why the "hardware" would have any effect, but this is a Hyper-V 2012r2 G2 VM

Revision history for this message
Michael Hudson-Doyle (mwhudson) wrote :

Ah so I think what's happening here is that when you select "use DHCPv6", the nameservers configured when you configured IPv4 are forgotten. If you configure DHCPv6 first and then configure IPv4 does that work?

This clearly isn't sensible behaviour.

Revision history for this message
Arne Lovius (automaton) wrote :

after changing to use DHCPv6 and going back, the DNS servers and search domain are empty

Revision history for this message
Arne Lovius (automaton) wrote :

after adding DNS servers and search domain and then continuing, the full log now shows the nameservers and search domain, the install completes, and I have IPv4 and IPv6 connectivity with working DNS

Going back and re-entering DNS servers and search domain during the install is a _workable_ method.

I would have thought that static V4 with DHCPv6 was not _that_ uncommon.

Revision history for this message
Michael Hudson-Doyle (mwhudson) wrote :

Thanks for checking. I wasn't meaning to propose what you did as a solution, although it just about qualifies as a workaround I guess, but by doing that you confirmed my suspicions as to what the problem was!

Changed in subiquity:
status: Incomplete → Triaged
summary: - installer static IPv4 DNS is not used
+ configuring DHCPv6 wipes out any nameservers set while configuring IPv4
Changed in debian-installer (Ubuntu):
status: Incomplete → Invalid
tags: added: id-5af9fc09f44d168618294a3a
Changed in subiquity:
importance: Undecided → Medium
To post a comment you must log in.
This report contains Public information  
Everyone can see this information.

Other bug subscribers

Remote bug watches

Bug watches keep track of this bug in other bug trackers.