rd.live.overlay.overlayfs doesn't seem to work when $DRACUT_SYSTEMD=1

[jdharms]

Describe the bug
I'm attempting to boot into a squashfs image with an overlayfs overlay. The switch root fails, here are some relevant lines from my rdsosreport.txt:

[   36.385975] localhost systemctl[782]: Got message type=error sender=org.freedesktop.systemd1 destination=n/a path=n/a interface=n/a member=n/a cookie=1 reply_cookie=1 signature=s error-name=org.freedesktop.DBus.Error.InvalidArgs error-message=Specified switch root path '/sysroot' does not seem to be an OS tree. os-release file is missing.

[   36.385975] localhost systemctl[782]: Failed to switch root: Specified switch root path '/sysroot' does not seem to be an OS tree. os-release file is missing.

[   36.385975] localhost systemctl[782]: Bus n/a: changing state RUNNING → CLOSED

[   36.386080] localhost systemd[1]: Failed to process message type=method_call sender=n/a destination=org.freedesktop.systemd1 path=/org/freedesktop/systemd1 interface=org.freedesktop.systemd1.Manager member=SwitchRoot cookie=1 reply_cookie=0 signature=ss error-name=n/a error-message=n/a: Specified switch root path '/sysroot' does not seem to be an OS tree. os-release file is missing.

If I remove or alter the line here: https://github.com/dracutdevs/dracut/blob/master/modules.d/90dmsquash-live/dmsquash-live-root.sh#L394 to add the overlayfs even with DRACUT_SYSTEMD is not zero then my system boots exactly how I would expect it to.

Is this conditional necessary? Is systemd not doing something that dracut assumes it should do?

Distribution used
Ubuntu 22.04

Dracut version
dracut --version reports only dracut. apt info dracut reports version 051-1. Was installed via apt.

Init system
systemd

To Reproduce
My dracut.conf:

hostonly=no
hostonly_cmdline="root=live:UUID=xxxxxxx-xxxx debug mitigations=auto rd.live.debug=1 rd.live.overlay.overlayfs=1 rd.shell"
compress=xz
uefi=yes
uefi_stub=/usr/lib/...........
add_dracutmodules+=" dmsquash-live "

/LiveOS/squashfs.img is a squashfs image containing a flat ubuntu root fs.

Expected behavior
Should set up an overlayfs fs over the squashfs image

[alexxy]

Also noticed same issue with dracut 053 using livenet, however starting

systemctl start sysroot.mount 

mounts /sysroot

[LaszloGombos]

@jdharms If you do not actually need systemd in your initramfs, you can disable it and just specify the dracut modules you actually need, e.g.

dracutmodules+="dmsquash-live"

There is a PR up for review for a test case that uses this technique and it is passing (against latest upstream) - https://github.com/dracutdevs/dracut/pull/1813/files#diff-6aa993c0ff374636137737561ae60ed7e576e1891e210e322680f9662ebdef13R110

[alexxy]

Also seems like its related to systemd version. Like a issue #1822. I found old version of live image with dracut 053 and systemd 249 and it works with same setup, however systemd 250+ stopped working

[FGrose]

@jdharms Please adjust dmsquash-live-root.sh lines 9-13 to

if getargbool 0 rd.live.debug -n -y rdlivedebug; then
    [ -z "$DRACUT_SYSTEMD" ] && exec > /run/initramfs/liveroot.$$.out 2>&1
    set -x
    export RD_DEBUG=yes
    [ "$BASH" ] && export \
        PS4='+ (${BASH_SOURCE}@${LINENO}): ${FUNCNAME[0]:+${FUNCNAME[0]}(): }'
fi

and then report the relevant journal section or /run/initramfs/liveroot.$$.out.

(Notice that if your flat rootfs does not contain the empty directory /proc, the test at line 304
elif [ -d /run/initramfs/squashfs/proc ]; then will fail.)

[LaszloGombos]

I think this (or similar) issue can be reproduced by running test-16 with the following change in the source tree

--- a/test/TEST-16-DMSQUASH/test.sh
+++ b/test/TEST-16-DMSQUASH/test.sh
@@ -136,8 +136,8 @@ SUBSYSTEM=="block", ENV{ID_FS_TYPE}=="ntfs", ENV{ID_FS_TYPE}="ntfs3"
 EOF
 
     "$basedir"/dracut.sh -l -i "$TESTDIR"/overlay / \
-        --modules "test dash dmsquash-live qemu" \
+        --modules "test dash dmsquash-live qemu dracut-systemd" \