UKI: Reduce Ubuntu base image sizes

[mauromorales]

We are hitting a limit with EFI images and bumping into systemd/systemd#25911, so we want to reduce the base image size

[mauromorales]

biggest offenders:

6684    python3.11-minimal
6994    grub-efi-amd64-signed
7000    coreutils
7736    perl-base
8110    libmagic-mgc
8435    libpython3.11-stdlib
9960    grub-efi-amd64-bin
10243   udev
10460   systemd
12199   intel-microcode
12520   grub-common
13413   libc6
13955   linux-image-6.5.0-15-generic
17815   perl-modules-5.36
20066   neovim-runtime
20084   iso-codes
28850   libperl5.36
36251   libicu72
37051   linux-modules-6.5.0-15-generic
105454  linux-modules-extra-6.5.0-15-generic
107752  snapd
414784  linux-firmware

[mauromorales]

can we reduce the size of the initrd file?

root@9db85a46b070:/# ls -lahs /boot/
total 103M
4.0K drwxr-xr-x 1 root root 4.0K Feb 22 11:54 .
4.0K drwxr-xr-x 1 root root 4.0K Feb 22 13:29 ..
8.2M -rw------- 1 root root 8.2M Jan 11 12:47 System.map-6.5.0-17-generic
276K -rw-r--r-- 1 root root 275K Jan 11 12:47 config-6.5.0-17-generic
   0 lrwxrwxrwx 1 root root   27 Feb 22 11:54 initrd.img -> initrd.img-6.5.0-17-generic
 81M -rw------- 1 root root  81M Feb 22 11:54 initrd.img-6.5.0-17-generic
   0 lrwxrwxrwx 1 root root   27 Feb 22 11:54 initrd.img.old -> initrd.img-6.5.0-17-generic
   0 lrwxrwxrwx 1 root root   24 Feb 22 11:54 vmlinuz -> vmlinuz-6.5.0-17-generic
 14M -rw------- 1 root root  14M Jan 11 12:48 vmlinuz-6.5.0-17-generic
   0 lrwxrwxrwx 1 root root   24 Feb 22 11:54 vmlinuz.old -> vmlinuz-6.5.0-17-generic

[liyimeng]

will this also help #2262?

[mauromorales]

@liyimeng just on the size of Kairos related binaries, which are now compressed

[jimmykarily]

We did some work to makes it smaller already. Let's close this and revisit if we have more ideas on how to improve more.