This reverts commit c4e69348aed2e89bdef0187afe79da18d855eb8c as
the more debugging is needed for autopkgtest failures and is
therefore blocking apparmor fixes for cloud images.
In cloud-init version 24.3, single process mode where a shared python
systemd service cloud-init-main. In that release, cloud-init.service was
renamed cloud-init-network.service to better clarify cloud-init's
systemd unit names relative to the cloud-init boot stages.
This rename only applies to Oracular and newer releases.
See: https://discourse.ubuntu.com/t/announcement-cloud-init-perfomance-optimization-single-process/47505
functions drops in a complete override for cloud-init.service. That
override in /etc/systemd/system needs to be renamed and refreshed to
latest single process configuration.
LP: #2081325
kdump-tools uses ucf for config file management and naively
modifying the config file meant for the target system directly
will cause the file hash to not get updated in the ucf database.
This will then cause later modifications to fail because
"there's nothing to do". Although actually doing the modification
to the ucf database is messy. Let's just modify the file in the live
layer to get the behavior we want there.
We install the kdump-tools package to minimal layer via inclusion in the
desktop-minimal seed, but it is enabled by default. Include a new chroot
hook to set USE_KDUMP=0 to make sure it's disabled by default and let
the installer decide to enable it or not.
We install the kdump-tools package to minimal layer via inclusion in the
server-minimal seed, but it is enabled by default. Include a new chroot
hook to set USE_KDUMP=0 to make sure it's disabled by default and let
the installer decide to enable it or not.
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.
