From: Emanuele Giuseppe Esposito eesposit@redhat.com
redhat: create 'systemd-volatile-overlay' addon for UKI
Create 'systemd.volatile=overlay' UKI addon. This is option allows to overlay the whole root with an overlayfs which is backed up in tmpfs. Which means that any write will be lost on reboot.
This option is especially useful when the root is dm-verity protected, which means it is mounted as RO, and the workload type running on the system doesn't rely on storing data, such as running containers.
Note that systemd.volatile=state doesn't really work on Fedora/RHEL, as it just mounts tmpfs on /var but root stays RW (should be RO according with docs), and systemd.volatile=etc puts a tmpfs on top of root, resetting the system (and most importantly /etc) completely which then makes the system unusable.
Signed-off-by: Emanuele Giuseppe Esposito eesposit@redhat.com
diff --git a/redhat/uki_addons/common/systemd-volatile-overlay.addon b/redhat/uki_addons/common/systemd-volatile-overlay.addon new file mode 100644 index blahblah..blahblah 100644 --- /dev/null +++ b/redhat/uki_addons/common/systemd-volatile-overlay.addon @@ -0,0 +1 @@ +systemd.volatile=overlay \ No newline at end of file
-- https://gitlab.com/cki-project/kernel-ark/-/merge_requests/3809
From: Jan Stancek on gitlab.com https://gitlab.com/cki-project/kernel-ark/-/merge_requests/3809#note_2438129...
Do we know when (what version) does support for systemd.volatile=overlay start?
From: Emanuele Giuseppe Esposito on gitlab.com https://gitlab.com/cki-project/kernel-ark/-/merge_requests/3809#note_2438199...
I quickly checked with Vitaly and it should be supported since v242, since RHEL 9 supports v252 it should be all good I wouldn't even remotely consider of backporting this in previous version :smile:
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