[Bug 1916503] Re: Networking does not work after upgrading libnetplan0

[Lukas Märdian]

It appears there has been some ABI breakage, similar to LP: #1922898

Newer versions of netplan (starting with 0.104) use a strict version
dependency to upgrade libnetplan and netplan.io at the same time, to
avoid such issues. In addition to being much more careful wrt. ABI
breaking changes!

** Changed in: netplan.io (Ubuntu)
       Status: New => Fix Released

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to netplan.io in Ubuntu.
Matching subscriptions: foundations-bugs
https://bugs.launchpad.net/bugs/1916503

Title:
  Networking does not work after upgrading libnetplan0

Status in netplan.io package in Ubuntu:
  Fix Released

Bug description:
  I upgraded libnetplan0 on our AWS EC2 from 0.99-0ubuntu3~20.04.2 to
  0.101-0ubuntu3~20.04.2, but did not upgrade netplan.io, which remained
  at version 0.99-0ubuntu1. On system reboot, our networking was not
  configured properly and our AWS EC2 instance was unreachable via SSH.

  I believe the issue is that libnetplan 0.101-0ubuntu3~20.04.2 is
  incompatible with netplan.io 0.99-0ubuntu1. However, "apt show
  netplan.io=0.99-0ubuntu1" lists the dependency libnetplan0 (>=
  0.99-0ubuntu1). I believe this is incorrect, since from this
  experience libnetplan 0.101-0ubuntu3~20.04.2 appears to be
  incompatible with netplan.io 0.99-0ubuntu1.

  I suspected that the issue was with netplan by inspecting
  /var/log/syslog, which had these entries after upgrading libnetplan0 -
  some errors from systemd-networkd and then interface ens5 not coming
  up:

  Feb 18 17:20:44 xxxx systemd-networkd[446]: /run/systemd/network/10-netplan-ens5.network:4: Maximum transfer unit (MTU) value out of range. Permitted range is 68…4294967295, ignoring: -1
  Feb 18 17:20:44 xxxx systemd-networkd[446]: /run/systemd/network/10-netplan-ens5.network: No valid settings found in the [Match] section, ignoring file. To match all interfaces, add Name=* in the [Match] section.
  Feb 18 17:20:44 [omitted] cloud-init[460]: Cloud-init v. 20.4.1-0ubuntu1~20.04.1 running 'init' at Thu, 18 Feb 2021 17:20:44 +0000. Up 5.06 seconds.
  Feb 18 17:20:44 [omitted] cloud-init[460]: ci-info: +++++++++++++++++++++++++++Net device info++++++++++++++++++++++++++++
  Feb 18 17:20:44 [omitted] cloud-init[460]: ci-info: +--------+-------+-----------+-----------+-------+-------------------+
  Feb 18 17:20:44 [omitted] cloud-init[460]: ci-info: | Device |   Up  |  Address  |    Mask   | Scope |     Hw-Address    |
  Feb 18 17:20:44 [omitted] cloud-init[460]: ci-info: +--------+-------+-----------+-----------+-------+-------------------+
  Feb 18 17:20:44 [omitted] cloud-init[460]: ci-info: |  ens5  | False |     .     |     .     |   .   |     [omitted]     |
  Feb 18 17:20:44 [omitted] cloud-init[460]: ci-info: |   lo   |  True | 127.0.0.1 | 255.0.0.0 |  host |         .         |
  Feb 18 17:20:44 [omitted] cloud-init[460]: ci-info: |   lo   |  True |  ::1/128  |     .     |  host |         .         |
  Feb 18 17:20:44 [omitted] cloud-init[460]: ci-info: +--------+-------+-----------+-----------+-------+-------------------+
  Feb 18 17:20:44 [omitted] cloud-init[460]: ci-info: +++++++++++++++++++Route IPv6 info+++++++++++++++++++
  Feb 18 17:20:44 [omitted] cloud-init[460]: ci-info: +-------+-------------+---------+-----------+-------+
  Feb 18 17:20:44 [omitted] cloud-init[460]: ci-info: | Route | Destination | Gateway | Interface | Flags |
  Feb 18 17:20:44 [omitted] cloud-init[460]: ci-info: +-------+-------------+---------+-----------+-------+
  Feb 18 17:20:44 [omitted] cloud-init[460]: ci-info: +-------+-------------+---------+-----------+-------+

  
  I was able to recover the EC2 instance by attaching the root EBS volume to another working EC2 instance and manually installing netplan.io=0.101-0ubuntu3~20.04.2 using chroot. When I rebooted, the server was able to boot with networking.

  To reproduce, upgrade libnetplan0 from 0.99-0ubuntu3~20.04.2 to
  0.101-0ubuntu3~20.04.2, but keep netplan.io at version version
  0.99-0ubuntu1 and reboot.

  I'm using apt repositories:
  http://us-east-1.ec2.archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages
  http://us-east-1.ec2.archive.ubuntu.com/ubuntu focal/main amd64 Packages

  Description:    Ubuntu 20.04.2 LTS
  Release:        20.04

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/netplan.io/+bug/1916503/+subscriptions