By placing the kernel in minimal, we can achieve the following
improvements:
1. Space savings - there are redundant packages present in the ship-live
pool and in the live layer. Adding the kernel to minimal means that
the kernel is already in the live layer, and we don't then also need
it in the pool.
2. Time savings - informal vm testing suggests more than a minute
improvement to have the kernel preinstalled over installing it at
runtime.
As always, there is a cost tradeoff:
1. If a different kernel is desired, we need to be able to remove this
preinstalled kernel. Relevant curtin and subiquity changes are
already landed.
2. When installing that other kernel, it'll take longer than today due
to still needing to install a kernel at runtime + the time cost of
removing the preinstalled kernel.
Support some systems which don't handle partition numbers
higher than 15. (LP: #2072929)
Partition 16 was added for /boot to enable cloud FDE (commit a8b2a9b01)
Ubuntu Studio wants to add a minimal installation. The individual tasks
are metapackages that can be installed by the ubuntustudio-desktop task.
With that in mind, we would like to reintroduce
ubuntustudio-desktop-core as a minimal installation. This is made much
easier with the layered images compared to the package removal format
used by ubiquity. This also means ubuntustudio-desktop-core becomes the
base seed.
If I'm missing anything, please advise.
System override drop-ins cannot redact dependencies (Before or After) and
thus require a full unit override. Avoid writing the unit file delivered
by cloud-init deb package in /lib/systemd/system/cloud-init.service because
it will generate warnings fron debsums -c about modified files.
The correct place to provide a full unit override is in
/etc/systemd/system/cloud-init.service in order to drop
Before=sysinit.target from the packaged cloud-init.service file.
Note vigilance will be needed across cloud-init SRU boundaries to ensure
we sync any cloud-init.service unit changes that are introduced to
stable releases because livecd-rootfs is overriding the whole file.
LP: #2069391
The lowlatency kernel will eventually undergo deprecation. Rather than
wait for such a time to happen and be reactive, Ubuntu Studio would
rather be proactive about this now that the generic kernel can act as a
lowlatency kernel with certain command line parameters as outlined by
https://discourse.ubuntu.com/t/fine-tuning-the-ubuntu-24-04-kernel-for-low-latency-throughput-and-power-efficiency/44834.
As such, we have modified our `ubuntustudio-lowlatency-settings`
package, which installs `/etc/default/grub.d/ubuntustudio.cfg` with the
following line:
-GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT threadirqs"
+GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT preempt=full
nohz_full=all threadirqs"
Additionally, that same file used to set "GRUB_FLAVOUR_ORDER" which is
no longer needed.
unminimize is currently present at /usr/local/sbin/unminimize,
which is spit out by livecd-rootfs currently. We'd like to switch
that to use the packaged unminimize, which will be at
/usr/bin/unminimize instead.
There was a change made by me in https://code.launchpad.net/~philroche/livecd-rootfs/+git/livecd-rootfs/+merge/466388
as part of LP: #2066905 to remove references to LXD in the unminimize scripts
but I also removed the calls to `unminimize` in error.
This still needs to run but without any references to LXD which no longer
needs to be `unminimized` via snap installation.
The ubuntu-core-installer image is an installer that installs ubuntu
core. The environment the installer runs in is similar to the server
installer but it has a source catalog entry that points to the model
created in ubuntu-core-installer/hooks/05-prepare-image.binary, which
subiquity knows how to install.
With current kernel we need to specify the SBI driver
for the early console to work.
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
fix: No longer install LXD snap in unminimize script (LP: #2066905)
The LXD snap is no longer seeded in any images since Noble+ so the LXD related unminimize logic in
./live-build/auto/build?h=ubuntu/noble and ./live-build/ubuntu-server/hooks/01-unminimize.chroot_early
is no longer required.
lxd-installer can remain installed.
MP: https://code.launchpad.net/~philroche/livecd-rootfs/+git/livecd-rootfs/+merge/466316
The LXD snap is no longer seeded in any images since Noble+ so the LXD related unminimize logic in
./live-build/auto/build?h=ubuntu/noble and ./live-build/ubuntu-server/hooks/01-unminimize.chroot_early
is no longer required.
lxd-installer can remain installed.
Dan Bungert
Michael Hudson-Doyle
Sergio Costas Rodriguez
Chris Peterson
Utkarsh Gupta
Simon Poirier
Cody Shepherd
Steve Langasek
Łukasz 'sil2100' Zemczak
Heinrich Schuchardt
Erich Eickmeyer
Chad Smith
Zhai Zhaoxuan
Philip Roche
Brian Murray