Re: [PATCH] debianize: handle .triggers and .service files

["MOESSBAUER, Felix" <felix.moessbauer@siemens.com>]

On Wed, 2023-11-15 at 09:36 +0100, Jan Kiszka wrote:
> On 14.11.23 21:22, 'MOESSBAUER, Felix' via isar-users wrote:
> > On Tue, 2023-11-14 at 20:54 +0100, 'Cedric Hombourger' via isar-
> > users
> > wrote:
> > > Some packages need to update/rebuild the initramfs and this is
> > > particularly
> > > slow on Debian systems (which are not using more modern
> > > technologies
> > > such
> > > as dracut or mkosi). Instead of having each package call update-
> > > initramfs,
> > > use a trigger instead to have dpkg defer that call to the very
> > > end of
> > > the
> > > transaction. Many packages also failed to rebuild the initramfs
> > > when
> > > the
> > > package gets removed. Demonstrate use with initramfs-fsck-hook-
> > > ext4.
> > 
> > Hi Cedric,
> > 
> > thanks for bringing this up. Especially on non x86 builds the
> > update-
> > initramfs can take really long due to the emulation.
> > 
> > I also played around with disabling the initrd update during image
> > building of images with a custom initramfs (where the one from the
> > rootfs is anyways not used). However the issue is, that the config
> > change needs to be made in /etc/initramfs-tools/update-
> > initramfs.conf,
> > which is shipped by initramfs-tools (no conf.d style supported). By
> > that, we would need to add this package to the default set of
> > packages
> > which I also dislike.
> > 
> > What I don't understand is how the initrd trigger should help. The
> > /usr/sbin/update-initramfs internally already detects the
> > invocation
> > via dpkg and dispatches to the trigger, so manually adding this is
> > nice
> > syntax wise, but does not make a difference in performance.
> > 
> > Ideally, we don't update the initrd at all during package install,
> > but
> > just generate it at do_rootfs_postprocess.
> > 
> 
> There is actually an issue already in Debian itself which I started
> to
> examine during Debconf but was distracted: If you install a minimal
> rootfs with kernel, that will already run the initramfs generation
> twice, although it should do it once only. That said, anything on top
> may be related to missing proper usage of triggers.

Ok... can you provide a link to the issue?

Regarding the triggers: The triggers itself work properly, but they are
called once per apt install/remove invocation, and as we have multiple
apt calls in ISAR (within a single build), also the triggers are called
multiple times. We really need to fully disable the initramfs
generation and call it manually at the end of the rootfs install.

Felix

> 
> Jan
>