Table of Contents

Contents

  1. Introduction
      1. Support lifespan
      2. Official flavor release notes
  2. Get Ubuntu 20.04.6 LTS
    1. Download Ubuntu 20.04.6 LTS
    2. Upgrading from Ubuntu 18.04 LTS or 19.10
      1. Upgrades on i386
  3. New Features in 20.04 LTS
    1. RISC-V image
    2. Updated Packages
      1. Linux Kernel
      2. Toolchain Upgrades 🛠️
      3. Ubuntu Desktop
    3. Network configuration
    4. Storage/File Systems
      1. ZFS 0.8.3
    5. Other base system changes since 18.04 LTS
      1. Python3 by default
      2. Snap Store
    6. Ubuntu Server
      1. Installer
      2. QEMU
      3. libvirt
      4. dpdk
      5. Open vSwitch
      6. Chrony
      7. cloud-init
      8. PHP 7.4
      9. Ruby 2.7
      10. Ruby on Rails 5.2.3
      11. Ubuntu HA/Clustering
      12. isc-kea 1.6 stable track
      13. Bind 9.16
      14. OpenSSH updates with U2F Support
      15. HAProxy 2.0
      16. Apache, TLSv1.3, client cert auth
      17. Samba 4.11
      18. PostgreSQL 12
      19. nginx
      20. Squid 4.x
      21. s390x
      22. OpenStack Ussuri
      23. Ceph
    7. Cloud Images ☁
      1. Amazon Web Services (AWS)
      2. Google Compute Engine
      3. Microsoft Azure
      4. Vagrant
    8. Raspberry Pi
  4. Known issues
    1. Installer and live session
    2. Distribution Upgrades
    3. Desktop
    4. Raspberry Pi
    5. RISC-V
    6. Server
    7. General
  5. Official flavours
  6. More information
      1. Reporting bugs
      2. Participate in Ubuntu
      3. More about Ubuntu

Introduction

These release notes for Ubuntu 20.04 LTS (Focal Fossa) provide an overview of the release and document the known issues with Ubuntu 20.04 LTS and its flavors. For details of the changes applied since 20.04, please see the 20.04.6 change summary. The release notes for 20.04, 20.04.1, 20.04.2, 20.04.3, 20.04.4 and 20.04.5 change summary are available as well.

Support lifespan

Maintenance updates will be provided for 5 years until April 2025 for Ubuntu Desktop, Ubuntu Server, Ubuntu Cloud, and Ubuntu Core. All the remaining flavours will be supported for 3 years. Additional security support is available with ESM (Extended Security Maintenance).

Official flavor release notes

Find the links to release notes for official flavors here.


Get Ubuntu 20.04.6 LTS

Download Ubuntu 20.04.6 LTS

Images can be downloaded from a location near you.

You can download ISOs and flashable images from:

https://releases.ubuntu.com/20.04/ (Ubuntu Desktop and Server for AMD64)
http://cdimage.ubuntu.com/ubuntu/releases/20.04/release/ (Less Frequently Downloaded Ubuntu Images)
http://cloud-images.ubuntu.com/daily/server/focal/current/ (Ubuntu Cloud Images)
http://cdimage.ubuntu.com/kubuntu/releases/20.04/release/ (Kubuntu)
http://cdimage.ubuntu.com/lubuntu/releases/20.04/release/ (Lubuntu)
http://cdimage.ubuntu.com/ubuntu-budgie/releases/20.04/release/ (Ubuntu Budgie)
http://cdimage.ubuntu.com/ubuntukylin/releases/20.04/release/ (Ubuntu Kylin)
https://ubuntu-mate.org/download/ (Ubuntu MATE)
http://cdimage.ubuntu.com/ubuntustudio/releases/20.04/release/ (Ubuntu Studio)
http://cdimage.ubuntu.com/xubuntu/releases/20.04/release/ (Xubuntu)

Upgrading from Ubuntu 18.04 LTS or 19.10

To upgrade on a desktop system:

To upgrade on a server system:

Note that the server upgrade will use GNU screen and automatically re-attach in case of dropped connection problems.

The -d switch is necessary to upgrade from Ubuntu 18.04 LTS as upgrades have not yet been enabled and will only be enabled after the first point release of 20.04 LTS.

Upgrades on i386

Users of the i386 architecture will not be presented with an upgrade to Ubuntu 20.04 LTS. Support for i386 as a host architecture was dropped in 19.10.

New Features in 20.04 LTS

RISC-V image

RISC-V images for SiFive HiFive Unleashed and Unmatched boards are now available, which can also be used as a VM with QEMU on any Ubuntu 20.04 machine. For more details see RISC-V page.

Updated Packages

As with every Ubuntu release, Ubuntu 20.04 LTS comes with a selection of the latest and greatest software developed by the free software community.

Linux Kernel

Ubuntu 20.04 LTS is based on the long-term supported Linux release series 5.4. HWE stack updated to Linux release series 5.8.

NOTE: Users who installed from Ubuntu Desktop media should see the note about desktop tracking the rolling hardware enablement kernel series by default here.

Notable features and enhancements in 5.4 since 5.3 include:

Other notable kernel updates to 5.4 since version 4.15 released in 18.04 LTS include:

Toolchain Upgrades 🛠️

Ubuntu 20.04 LTS comes with refreshed state-of-the-art toolchain including new upstream releases of glibc 2.31, ☕ OpenJDK 11, rustc 1.41, GCC 9.3, 🐍 Python 3.8.2, 💎 ruby 2.7.0, php 7.4, 🐪 perl 5.30, golang 1.13.

Ubuntu Desktop

Network configuration

With this Ubuntu release, netplan.io has grown multiple new features, some of which are:

Storage/File Systems

ZFS 0.8.3

Continuing with what started in the Eoan release, Ubuntu Focal ships zfs 0.8.3. Compared to what was available in the previous LTS release, zfs 0.8 brings many new features. Highlights include:

Upstream 0.8.0 release notes: https://github.com/openzfs/zfs/releases/tag/zfs-0.8.0

Also checkout 0.8.1, 0.8.2 and 0.8.3 for more details.

Other base system changes since 18.04 LTS

Python3 by default

In 20.04 LTS, the python included in the base system is Python 3.8. Python 2.7 has been moved to universe and is not included by default in any new installs.

Remaining packages in Ubuntu which require Python 2.7 have been updated to use /usr/bin/python2 as their interpreter, and /usr/bin/python is not present by default on any new installs. On systems upgraded from previous releases, /usr/bin/python will continue to point to python2 for compatibility. Users who require /usr/bin/python for compatibility on newly-installed systems are encouraged to install the python-is-python3 package, for a /usr/bin/python pointing to python3 instead.

Due to this transition the legacy python and python-minimal packages might be removed during an upgrade, being replaced by the python2 and python2-minimal packages as dependencies of the python-is-python2 package.

Snap Store

The Snap Store (snap-store) replaces ubuntu-software as the default tool for finding and installing packages and snaps.

Ubuntu Server

Installer

The live server installer is now the preferred media to install Ubuntu Server on all architectures.

Besides architecture support, the main user visible new features are support for automated installs and being able to install the bootloader to multiple disks (for a more resilient system).

There have been many other fixes under the hood to make using encryption easier, better support installing to multipath disks, more reliable installation onto disks that have been used in various ways and allowing failures to be reported more usefully.

Starting from Ubuntu Server 20.04.2 the ISO images can optionally boot the installer using the HWE kernel. In this case the installed system will automatically make use of the HWE stack.

QEMU

QEMU was updated to 4.2 release. There is so much that it is hard to select individual improvements to highlight, here just a few:

Therefore please see the full change logs 4.2 and 4.1 for major changes since Ubuntu 19.10.

For Upgraders from Ubuntu 18.04 please also check out 4.0, 3.1, 3.0 and 2.12.

When upgrading it is always recommended to upgrade the machine types allowing guests to fully benefit from all the improvements and fixes of the most recent version.

upgrading from 19.10

For trimmed down container like isolation use-cases the new qemu has the microvm machine type which can be combined with the qboot ROM (available as bios-microvm.bin) to provide a reduced feature set at a much faster startup time. To further emphasize that you can use the package qemu-system-x86-microvm which provides an alternative QEMU binary stripped of all features not needed these use cases as sugegsted by the qboot ROM.

The VMX related features can now be controlled individually instead of just vmx on/off. Due to that the VMX-subfeatures of certain CPU types might have slightly changed (matching those of the selected CPU type now instead of almost randomly depending on the underlying hardware). In general it is - and always was - recommended to use a well defined cpu type when defining a guest, this is also what almost all higher level management tools from virt-manager to openstack will do. But if you want the most generic and compatible cpu but also enable VMX please use the type kvm64 instead of qemu64 now.

People that like to work or experiment with nvdimms and persistent memory QEMU now has pmem and nvdimm support enabled in Ubuntu Focal Fossa.

upgrading from 18.04

QEMU now has virglrenderer enabled which allows to create a virtual 3D GPU inside QEMU virtual machines. That is inferior to GPU passthrough, but can be handy if the platform used lacks the capability for classic PCI passthrough as well as more modern mediated devices.

The graphical QEMU back-end is now based on GTK instead of SDL. That provides much better Desktop integration and is often faster.

libvirt

libvirt was updated to version 6.0. See the upstream change log for details since version 5.6 that was in Ubuntu 19.04 or further back since verison 4.0 that was in Ubuntu 18.04.

upgrading from 19.10

Among many improvements worth to mention might be the features:

upgrading from 18.04

Worth mentioning is that libvirt can now enable QEMUs ability to use parallel connections for migration which can help to speed up migrations if one doesn't saturate your network yet.

Administrators might like the ease of a new local include apparmor to the libvirt-qemu profile that allows local overrides for special devices or paths matching your setup without conffile delta that has to be managed on later upgrades.

Added the ability to have GL enabled graphics as well as mediated devices to be configured while still being guarded by custom apparmor profiles generated per guest. This is required for the use of gpu based mediated devices as well as VirGL mentioned above in the qemu section.

Transition libvirt-bin -> libvirt-clients / libvirt-daemon / libvirt-daemon-system

Already in Ubuntu 18.04 the package was split from an almost single monolithic package libvirt-bin into three main components:

In a similar fashion rarely used and less supported sub-features like virtualbox and xen control, as well as uncommon storage options are broken out into various libvirt-daemon-driver-* packages. That allows to reduce the install footprint and active code in the majority of installations.

Packages and project had plenty of time to transition, so now the empty compatibility package libvirt-bin that was pulling in libvirt-daemon-system + libvirt-clients was finally dropped. If you happen to have scripts or third party components referring to the old name use the list above to select which new package makes most sense to you.

dpdk

Ubuntu 20.04 LTS includes the latest stable release 19.11.1 of the latest LTS series 19.11.x. The very latest (non-stable) version being 20.02 was not chosen for downstream projects of DPDK (like Open vSwitch) not being compatible yet.

See the 19.11 and 19.11.1 release notes for details.

upgrading from 18.04

DPDK dependencies were reorganized into more or less common/tested components. Due to that most DPDK installations will now have a smaller installation footprint and less potentially active code to care about.

Open vSwitch

Open vSwitch has been updated to 2.13.

Please read the 2.13 release notes for more detail.

Upgraders from 18.04 might also want to take a look at release notes of:

Chrony

Chrony been updated to version 3.5 which provides plenty of improvements in accuracy and controls. Furthermore it also adds additional isolation for non-x86 by enabling syscall filters on those architectures as well.

To further allow feeding Hardware time into Chrony the package GPSD is now also fully supported.

But still for simple time-sync needs the base system already comes with systemd-timesyncd. Chrony is only needed to act as a time server or if you want the advertised more accurate and efficient syncing.

cloud-init

Cloud-init was updated to version 20.1-10. Notable features include:

Cloud platform features

Networking features

Config module features

PHP 7.4

PHP 7.4 is a new feature update, bringing typed properties, arrow functions, weak references, and unpacking inside arrays among other things. For more information on the new features and improvements, see the PHP 7.4 Release Announcement.

For more details about deprecated functionality, and suggested replacements, see the PHP 7.4 Deprecated Features page. Migration guides to 7.4 from 7.3 or earlier versions of PHP are also available in the PHP Manual. Users coming from Ubuntu 18.04 will be moving from 7.2 to 7.4, so should also refer to the Migration guides to 7.3 from 7.2.

Ruby 2.7

The default Ruby interpreter was updated to version 2.7. It comes with some nice features and improvements like: Pattern Matching, REPL improvement, Compaction GC, Separation of positional and keyword arguments and much more. To have a broad overview about the cool features and improvements check the Ruby 2.7 Release Announcement.

Users coming from previous Ubuntu releases (from 18.04 on) will be moving from Ruby 2.5 to 2.7, in this case the Ruby 2.6 Release Announcement might be useful as well. An important thing to keep in mind is that some libraries are not bundled anymore in Ruby. If you need them please install them separately:

For more information check out this blog post.

Ruby on Rails 5.2.3

Ruby on Rails was updated to version 5.2.3. From users coming from Ubuntu 18.04 is a major change, moving from version 4.2.10 to 5.2.3. Some highlights are: addition of Action Cable framework, option to create slimmed down API only appli cations, Active Record attributes API and so on. Check the Ruby on Rails 5 and 5.2 Release Notes for an overview.

If you need to upgrade your Ruby on Rails application please take a look at the upstream upgrading guide.

Ubuntu HA/Clustering

Kronosnet

kronosnet (or knet for short) is the new underlying network protocol for Linux HA components (corosync), that features the ability to use multiple links between nodes, active/active and active/passive link failover policies, automatic link recovery, FIPS compliant encryption (NSS and/or OpenSSL), automatic PMTUd and in general better performance compared to the old network protocol.

Main NEW features:

Corosync

From Corosync 3 release notes:

Corosync 3.0 contains many interesting features mostly related to usage of Kronosnet (https://kronosnet.org/) as a default (and preferred) network transport.

Pacemaker

From Pacemaker 2.0 release notes:

The main goal of the 2.0 release was to remove support for deprecated syntax, along with some small changes in default configuration behavior and tool behavior. Highlights: Only Corosync version 2 and greater is now supported as the underlying cluster layer. Support for Heartbeat and Corosync 1 (including CMAN) is removed.

Rolling upgrades from Pacemaker versions earlier than 1.1.11 are not possible, even if the underlying cluster stack is corosync 2 or greater. Other rolling upgrades, from newer versions on top of corosync 2 or greater, should be possible with little to no change.

Resource Agents

Cluster Resource Agents (RAs), compliant with the Open Cluster Framework (OCF) specification, used to interface with various services in a High Availability environment managed by the Pacemaker resource manager.

Complete Changelog:

Fence Agents

Fence Agents is a collection of scripts to handle remote power management for several devices. They allow failed or unreachable nodes to be forcibly restarted and removed from the cluster.

keepalived

Failover and monitoring daemon for LVS clusters, used for monitoring real servers within a Linux Virtual Server (LVS) cluster. It can be configured to remove real servers from the cluster pool if they stop responding, as well as send a notification email to make the admin aware of the service failure.

isc-kea 1.6 stable track

Even though it's a Universe package, isc-kea is a promising new dhcp server from the same upstream that created Bind and isc-dhcp. For Focal, we updated it to the 1.6.x stable series.

Upstream 1.6.0 release notes: https://downloads.isc.org/isc/kea/1.6.0/Kea160ReleaseNotes.txt

Upstream 1.6.2 release notes (version currently in Focal): https://downloads.isc.org/isc/kea/1.6.2/Kea162ReleaseNotes.txt

Bind 9.16

Bind has been updated to the new stable release series from upstream: 9.16.x.

Important packaging changes are:

Upstream blog post about major changes in bind9 9.16.0: https://www.isc.org/blogs/bind9.16.0_released/

More detailed release notes: https://downloads.isc.org/isc/bind9/9.16.0/RELEASE-NOTES-bind-9.16.0.html

Presentation about the development of bind9 culminating in this new release: https://youtu.be/5math9Oy97s?t=46

OpenSSH updates with U2F Support

OpenSSH 8.2 added support for U2F/FIDO hardware devices to allow easy hardware-based two factor authentication. It is as simple as: 

# plug device in and:
$ ssh-keygen -t ecdsa-sk
Generating public/private ecdsa-sk key pair.
You may need to touch your authenticator to authorize key generation. <-- touch device
Enter file in which to save the key (/home/ubuntu/.ssh/id_ecdsa_sk): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/ubuntu/.ssh/id_ecdsa_sk
Your public key has been saved in /home/ubuntu/.ssh/id_ecdsa_sk.pub
The key fingerprint is:
SHA256:V9PQ1MqaU8FODXdHqDiH9Mxb8XK3o5aVYDQLVl9IFRo ubuntu@focal

Now just transfer the public part to the server to ~/.ssh/authorized_keys and you are ready to go: 

$ ssh -i .ssh/id_ecdsa_sk ubuntu@focal.server
Confirm user presence for key ECDSA-SK SHA256:V9PQ1MqaU8FODXdHqDiH9Mxb8XK3o5aVYDQLVl9IFRo <-- touch device
Welcome to Ubuntu Focal Fossa (development branch) (GNU/Linux 5.4.0-21-generic x86_64)
(...)
ubuntu@focal.server:~$

Upstream development of OpenSSH 8.2 in Debian has added support for an 'Includes' keyword in configuration files. This allows including additional configuration files via glob(3) patterns. By default the system sshd config (/etc/ssh/sshd_config) now includes files under /etc/ssh/sshd_config.d/*.conf. For each keyword encountered in configuration files, the first obtained value will be used. This is used in various Cloud Images to apply cloud-specific tuning while avoiding debconf prompts on package upgrade.

The effective configuration of sshd can be validated by running 'sudo sshd -T'. This reads and validates the config file(s) and prints the effective configuration before exiting.

See the upstream release notes for more details: https://www.openssh.com/txt/release-8.2

HAProxy 2.0

First introduced in Ubuntu Eoan 19.10, HAProxy in Focal is tracking the upstream LTS 2.0 branch. This series has many new features when compared to the previous 1.8 stable branch, and all are detailed in this blog post: https://www.haproxy.com/blog/haproxy-2-0-and-beyond/

Apache, TLSv1.3, client cert auth

Apache has been built with TLSv1.3 support, and depending on the server configuration, this might require clients performing certificate authentication to support Post Handshake Authentication (PHA). Not all TLSv1.3 capable clients can perform PHA, and will fail. Telltale signs of this being the error include these messages in the Apache server logs: 

AH: verify client post handshake
AH10158: cannot perform post-handshake authentication
SSL Library Error: error:14268117:SSL routines:SSL_verify_client_post_handshake:extension not received

In this case, if there is no updated client version, you should preferably disable TLSv1.3 on the affected client.

Chromium bug: https://bugs.chromium.org/p/chromium/issues/detail?id=911653

Firefox bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1511989 (fixed, can be enabled by toggling security.tls.enable_post_handshake_auth)

python httplib should enable post-handshake authentication for TLS 1.3: https://bugs.python.org/issue37440

Samba 4.11

Focal ships with Samba 4.11.x which introduces a number of changes. Of note we have:

Detailed upstream release notes for 4.11.0 can be seen here: https://www.samba.org/samba/history/samba-4.11.0.html

PostgreSQL 12

Focal is shipping postgresql-12, which has many improvements:

Upstream announcement: https://www.postgresql.org/about/news/1976/

Upstream release notes: https://www.postgresql.org/docs/12/release-12.html

nginx

Starting in Focal Fossa, nginx-core no longer ships with the legacy geoip module enabled by default. If you are using the legacy geoip module in nginx, you may run into upgrade issues if you do not deactivate the geoip module in your configuration. This was done as part of the deprecation of GeoIP legacy support.

Here are some scenarios you might encounter:

Squid 4.x

When upgrading from the previous LTS Ubuntu Bionic 18.04, the squid proxy cache will be at version 4. Among other changes, if you used custom logging format, be aware the redefining the build-in formats no longer works (upstream bug: https://bugs.squid-cache.org/show_bug.cgi?id=4905).

For example, if you were redefining the squid log format to change the timestamp, like this: 

logformat squid  %tg{%F %H:%M:%S %z} %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt

You now have to use another name, and specify that it should be used, like this: 

logformat custom-squid  %tg{%F %H:%M:%S %z} %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
access_log daemon:/var/log/squid/access.log custom-squid

s390x

IBM Z and LinuxONE / s390x-specific enhancements since 19.10 (partly not limited to s390x):

OpenStack Ussuri

Ubuntu 20.04 LTS includes the latest OpenStack release, Ussuri, as a preview with final release coming in the 20.04.1 LTS, including the following components:

Please refer to the OpenStack Ussuri release notes for full details of this release of OpenStack.

OpenStack Ussuri is also provided via the Ubuntu Cloud Archive for OpenStack Ussuri for Ubuntu 18.04 LTS users.

WARNING: Upgrading an OpenStack deployment is a non-trivial process and care should be taken to plan and test upgrade procedures which will be specific to each OpenStack deployment.

Make sure you read the OpenStack Charm Release Notes for more information about how to deploy Ubuntu OpenStack using Juju.

Ceph

Ceph was updated to the 15.2.1 release, Ceph Octopus. Please refer to the Ceph Octopus release notes for full details of this release.

This release of Ceph is also provided via the Ubuntu Cloud Archive for use with OpenStack Ussuri for Ubuntu 18.04 LTS users.

Cloud Images ☁

Amazon Web Services (AWS)

Google Compute Engine

Microsoft Azure

Vagrant

Raspberry Pi

Since the release of Ubuntu 19.10 Raspberry Pi 32-bit and 64-bit preinstalled images (renamed to raspi) support the Raspberry Pi 4 platform out-of-the-box. With this, our images now support almost all modern flavors of the Raspberry Pi family of devices (Pi 2B, Pi 3B, Pi 3A+, Pi 3B+, CM3, CM3+, Pi 4B). Starting from Ubuntu Server 20.04.2, support for the CM4 (all variants) and the Pi 400 has been added too.

Known issues

As is to be expected, with any release, there are some significant known bugs that users may run into with this release of Ubuntu 20.04 LTS. The ones we know about at this point (and some of the workarounds), are documented here so you don't need to spend time reporting these bugs again:

Installer and live session

Distribution Upgrades

Desktop

Raspberry Pi

RISC-V

Server

General

Official flavours

The release notes for the official flavors can be found at the following links:


More information

Reporting bugs

Your comments, bug reports, patches and suggestions will help fix bugs and improve the quality of future releases. Please report bugs using the tools provided.

If you want to help out with bugs, the Bug Squad is always looking for help.

Participate in Ubuntu

If you would like to help shape Ubuntu, take a look at the list of ways you can participate at

More about Ubuntu

You can find out more about Ubuntu on the Ubuntu website and Ubuntu wiki.

To sign up for future Ubuntu development announcements, please subscribe to Ubuntu's development announcement list at:

FocalFossa/ReleaseNotes (last edited 2023-03-21 10:40:56 by sil2100)