Default initrd is LZMA compressed, yet rebuilt initramfs are gzip?

[Dimitri John Ledkov]

$ file ~/Downloads/xenial-server-cloudimg-amd64-initrd-generic
/home/xnox/Downloads/xenial-server-cloudimg-amd64-initrd-generic: LZMA compressed data, streamed

Yet, in the base image I don't see that initramfs config options set COMPRESS=lzma. Thus first boot is lzma, yet on package upgrades i guess initrd would be regenerated as gzip...

Isn't the fact that all of our images use lzma and/or xz compression means we should switch Ubuntu default to lzma and/or xz as well?

[Dan Watkins (oddbloke)]

This is strange. I just booted an older image and then installed a
kernel:

$ file /boot/initrd.img-4.4.0-62-generic
/boot/initrd.img-4.4.0-62-generic: LZMA compressed data, streamed
$ sudo apt update
...
$ sudo apt upgrade
...
$ file /boot/initrd.img-4.4.0-6*
/boot/initrd.img-4.4.0-62-generic: gzip compressed data, last modified: Thu Mar 9 15:48:51 2017, from Unix
/boot/initrd.img-4.4.0-66-generic: gzip compressed data, last modified: Thu Mar 9 15:49:52 2017, from Unix

I'm guessing that it comes from "--initramfs-compression lzma" on line
613 of live-build/auto/config in livecd-rootfs; I'd expect this to
translate in to some configuration in the built image, but I guess not.

[Dimitri John Ledkov (xnox)]

I believe livecd-rootfs and live-build have been fixed for this.