Adding a new zram-generator package

[george-angel]

Adding sys-apps/zram-generator package

This resolves flatcar/Flatcar#905 . Issue explains the advantages of adding this package, but it effectively minimises the amount of config / setup a user needs to do as well as allowing for "dynamic" sizing of swap.

How to use

Create an image that contains this package and follow instructions at: https://wiki.gentoo.org/wiki/Zram#Using_systemd_zram-generator to use it.

Testing done

Built an image (based off current stable Flatcar) that includes sys-apps/zram-generator. Running with QEMU created the following config:

# /etc/systemd/zram-generator.conf

[zram0]
zram-size = min(ram, 8192)

Followed by:

$ sudo systemctl daemon-reload
$ sudo systemctl start dev-zram0.swap

And verified the swap was created:

$ zramctl
NAME       ALGORITHM DISKSIZE DATA COMPR TOTAL STREAMS MOUNTPOINT
/dev/zram0 lzo-rle       962M   4K   80B   12K       6 [SWAP]

Big thanks to @jepio with a lot of hand holding that was needed.

• Changelog entries added in the respective changelog/ directory (user-facing change, bug fix, security fix, update)
• Inspected CI output for image differences: /boot and /usr size, packages, list files for any missing binaries, kernel modules, config files, kernel modules, etc.

[jepio]

We need to add a keyword for arm64 to the profile, i can provide you a path tomorrow. Also a changelog entry would be nice.

[github-actions]

Build action triggered: https://github.com/flatcar/scripts/actions/runs/8420391132

[jepio]

I pushed the extra profile keywords. There's a followup required because gentoo rust ebuilds don't handle cross-compilation, the followup is in #1780.

Will merge this if the tests run as expected (there is an expected failure from the tang/tpm tests).

[ader1990]

Hello,

a mantle CI test might be useful to make sure this new feature has proper regression validation?
Also, I see an addition of static built binaries in the /boot partition, maybe a check on the size increase of the initrd/boot partition would be nice.

Thanks.

[jepio]

Hello,

a mantle CI test might be useful to make sure this new feature has proper regression validation? Also, I see an addition of static built binaries in the /boot partition, maybe a check on the size increase of the initrd/boot partition would be nice.

Thanks.

Are you sure? I only see this:

diff --git a/tmp/3909.0.0+nightly-20240314-2100-Ztgf0S b/tmp/.-I9wx8L
index 48c3a53899..d89eab3d35 100644
--- a/tmp/3909.0.0+nightly-20240314-2100-Ztgf0S
+++ b/tmp/.-I9wx8L
@@ -20854,6 +20854,7 @@
 /usr/lib/systemd/system-generators/systemd-run-generator
 /usr/lib/systemd/system-generators/systemd-system-update-generator
 /usr/lib/systemd/system-generators/systemd-veritysetup-generator
+/usr/lib/systemd/system-generators/zram-generator
 /usr/lib/systemd/system-preset
 /usr/lib/systemd/system-preset/99-default.preset
 /usr/lib/systemd/system-shutdown
@@ -21350,6 +21351,7 @@
 /usr/lib/systemd/system/systemd-userdbd.socket
 /usr/lib/systemd/system/systemd-vconsole-setup.service
 /usr/lib/systemd/system/systemd-volatile-root.service
+/usr/lib/systemd/system/systemd-zram-setup@.service
 /usr/lib/systemd/system/tcsd.service
 /usr/lib/systemd/system/time-set.target
 /usr/lib/systemd/system/time-sync.target

Re mantle: lets take care of this separately because it would be a lot of work for a first time contributor and the arm64 package doesn't work yet.

[ader1990]

Hello,
a mantle CI test might be useful to make sure this new feature has proper regression validation? Also, I see an addition of static built binaries in the /boot partition, maybe a check on the size increase of the initrd/boot partition would be nice.
Thanks.

Are you sure? I only see this:

diff --git a/tmp/3909.0.0+nightly-20240314-2100-Ztgf0S b/tmp/.-I9wx8L
index 48c3a53899..d89eab3d35 100644
--- a/tmp/3909.0.0+nightly-20240314-2100-Ztgf0S
+++ b/tmp/.-I9wx8L
@@ -20854,6 +20854,7 @@
 /usr/lib/systemd/system-generators/systemd-run-generator
 /usr/lib/systemd/system-generators/systemd-system-update-generator
 /usr/lib/systemd/system-generators/systemd-veritysetup-generator
+/usr/lib/systemd/system-generators/zram-generator
 /usr/lib/systemd/system-preset
 /usr/lib/systemd/system-preset/99-default.preset
 /usr/lib/systemd/system-shutdown
@@ -21350,6 +21351,7 @@
 /usr/lib/systemd/system/systemd-userdbd.socket
 /usr/lib/systemd/system/systemd-vconsole-setup.service
 /usr/lib/systemd/system/systemd-volatile-root.service
+/usr/lib/systemd/system/systemd-zram-setup@.service
 /usr/lib/systemd/system/tcsd.service
 /usr/lib/systemd/system/time-set.target
 /usr/lib/systemd/system/time-sync.target

Re mantle: lets take care of this separately because it would be a lot of work for a first time contributor and the arm64 package doesn't work yet.

looks good to me:

File    Size  Used Avail Use% Type
/boot   127M   62M   65M  49% vfat
/usr   1016M  463M  443M  52% btrfs
/       2.0G   36K  1.8G   1% ext4
SUM     3.1G  524M  2.3G  19% -

I will add the Mantle test to check if any PR goes beyond the 50% usage in /boot in the following days, so that we won't need to verify manually each time.

[jepio]

Thanks for the contribution @george-angel