bootloop after zfsbootmenue starts ubuntu / kubuntu

[online7878]

I used this script to install kubuntu 26.04 on my laptop but endet always in a boot loop. My config in principle was:

• zfs native encryption
• single nvme installation
• no secureboot
• autosign yes
• ZFSBOOTMENUE_BINARY_TYPE: EFI and LOCAL already used, did both not work

I found out that bootloops while using dracut instead of podman to create zfsbootmenue. Within the script it has also code with podman...

so how can I force the script to use podman instead of dracut? And I also know that podman does not work in chroot environment. But maybe it would work when while installing we would create a script to run on the host to build the image safely with podman.

or there is any other solution to that?

[Halfwalker]

Yeah, I pushed some changes (and have more to push soon) to use podman to use zbm-builder recently. There were changes in zbm that made local building really wonky, so going the "approved" method was best.

So far all my tests have worked though ... and I do have podman working within the chroot to build zbm via zbm-builder

[online7878]

Ok, thank you - so my problem does not have this origin, and it seems to be clear. I can enter the zfs boot menu, I also can enter the password for zfs native encription. But the system gets stuck when zfsbootmenue starts ubuntu or it gets stuck, when ubuntu is starting. See my screen pictue:

and here nano /etc/zfsbootmenu/config.yaml when I go into the power menu within zfsbootmenu:

So I do not see any mistake, and it shows, that the problem is not the zfsbootmenue but something else. Anyone any hint? What should I do to best contribute to a solution?

[Halfwalker]

That all looks OK to me, although that config.yaml is not what ZFS-root.sh creates - where did that come from ? This is on real hardware right ?

One thing I might suggest, when you're in zfsbootmenu, press ctrl-e to edit the kernel command line. Remove the "quiet" from it, then try booting. This will let it spit out all the boot messages as it goes - you might find something there. Also, can you do ctrl-j to jump into a chroot environment ?

I just pushed a bunch of changes/updates, specifically including the ZBM-builder section. I've used it in virtualbox and in qemu, and so far so good. NOENC, ZFSENC and LUKS all seem to be working cleanly. Perhaps try a clean new install.

[davestgermain]

I have a similar install. Also hanging on boot. Removing "quiet" from the kernel arguments doesn't make a difference. Nothing appears.

[Halfwalker]

That's weird _ haven't been able to replicate it. Can you provide the exact ZFS-root.conf you're using ? Obviously replace passwords etc.

Have you tried a packer build to see if that works ? For example, I do this

./run-packer.sh --docker --iso-src file:///qemu/ISOs --ubuntu-version 24.04.2 --discenc ZFSENC --set AUTHKEYS=halfwalker

to build a ZFS-native encrypted install via docker. If you have packer locally you can omit the --docker. This presumes you have a /qemu dir with ISOs and builds subdirs and the appropriate ISO available.

/qemu/ISOs/noble/ubuntu-24.04.2-live-server-amd64.iso

Then run it with ./run-kvm.sh (you might need to chown -R ${USER}:${USER} /qemu first) and log in as packer:packer with ssh -p 2222 packer@localhost

[davestgermain]

I figured it out, thanks to a hint from this thread

The kernel was failing to boot (locking up) unless maxcpus=1. After much trial and error, I found that changing the kernel option in /boot/efi/EFI/refind/refind.conf to this:

menuentry "ZFSBootMenu" {
  loader EFI/zfsbootmenu/zfsbootmenu.efi
  icon EFI/refind/icons/os_ubuntu.png
  options "maxcpus=1"
}

does the trick. ZFSBootMenu boots using 1 cpu, but the boot environment kernel can boot normally afterwards.

Might want to update the script to add this option, unless there's some other way to fix the problem.

[Halfwalker]

Huh, interesting. Something must have changed, since I've used virtualbox with multiple cpus before to boot tests builds. I'll push a change soon to add that, and perhaps a caveat in the README.

[Halfwalker]

Pushed - give it a go

[online7878]

I will try as soon as possible and give a feeback...

well, in my case it did not work. So I am not sure, what the problem is. I did a new download of ZFS-root and used my old config. Do you need my config to check? I do not know, what else i could do....

[davestgermain]

well, in my case it did not work. So I am not sure, what the problem is. I did a new download of ZFS-root and used my old config. Do you need my config to check? I do not know, what else i could do....

Since you are able to boot ZFSBootMenu, the only suggestion I have is to edit the kernel options on the ubuntu installation like this:
ro nomodeset earlycon=efifb keep_bootcon
That's how I was able to see that the kernel was locking up on SMP initialization. It may be locking up somewhere else for you.

[online7878]

thank you for the hint. where do I have to this? in the config? I did an install with that:
ZFSBOOTMENU_BINARY_TYPE=EFI

do I have after the installation to chroot into the system and change it? Sorry, I'm not native Linux user, but not to bad either....

[davestgermain]

thank you for the hint. where do I have to this? in the config? I did an install with that: ZFSBOOTMENU_BINARY_TYPE=EFI

do I have after the installation to chroot into the system and change it? Sorry, I'm not native Linux user, but not to bad either....

When you boot, press esc to get into the ZFSBootMenu, then ctrl-e to edit the kernel options for the selected boot environment. You can replace the whole line with ro nomodeset earlycon=efifb keep_bootcon, hit return, and return again to boot the kernel. The options won't persist between reboots, so you can go through this process of changing options to see what might be causing the hangup.

loglevel=7 is another option for printing a lot of debug info.

[Halfwalker]

I can try to replicate - would need your exact process and ZFS-root.conf if you're using one.

I just ran a regression build test, using packer to build all 3 variants (LUKS, ZFSENC and NOENC) of both noble/24.04.2 and resolute/26.04. All built cleanly, and the goss validation testing worked cleanly on all of them.

I'll be pushing updates to

• packer-validation/test-goss-manual.sh
• packer-validation/run-validation.sh
• .gitea/workflows/packer-build.yml (used to build matrix of variants)
• .gitea/workflows/packer-validate.yml (used to validate variants with goss)

An example of the goss results for packer-resolute-LUKS-2026-07-30-0028/goss-validation-2026-07-30-230531.txt You can see the tests that are run in packer-validation/tests/goss-smoke.yaml

Date:     Thu Jul 30 23:05:31 UTC 2026
Build:    /qemu/builds/packer-resolute-LUKS-2026-07-30-0028
Variant:  LUKS
Suite:    resolute
Pool:     resolute
Exit:     0

[INFO] ZFS-root Validation Runner
[INFO] ==========================

[INFO] VALIDATION_DIR = /home/packer/packer-validation
[INFO] Installing goss...
Downloading https://github.com/goss-org/goss/releases/download/v0.4.10/goss_0.4.10_linux_x86_64.tar.gz
Goss v0.4.10 has been installed to /root/.local/bin/goss
goss --version
goss version 0.4.10
Downloading https://raw.githubusercontent.com/goss-org/goss/master/extras/dgoss/dgoss
dgoss master has been installed to /root/.local/bin/dgoss
[INFO] Goss installed successfully: goss version 0.4.10
[INFO] Detecting system configuration...
[INFO] Detected pool: resolute
[INFO] Detected suite: resolute
[INFO] Detected encryption: LUKS
[INFO] Zrepl detected: yes
[INFO] Detected user: packer
[INFO] SecureBoot detected: no (sbctl not installed)
[INFO] Rescue dataset detected: yes
[INFO] Swap zvol detected: yes
[INFO] Dropbear in ZFSBootMenu detected: yes
[INFO] ZFSBootMenu binary type detected: LOCAL
[INFO] Using auto-generated vars: /tmp/goss-runtime-vars.yaml
[INFO] Running goss validation...
[INFO] Format: documentation

==========================================
VALIDATION RESULTS
==========================================

Command: zpool-status: exit-status: matches expectation: 0
Command: zpool-status: stdout: matches expectation: ["state: ONLINE"]
Command: zfs-datasets: exit-status: matches expectation: 0
Command: zfs-datasets: stdout: matches expectation: ["resolute/ROOT","resolute/ROOT/resolute","resolute/home","resolute/home/packer","resolute/home/root"]
Command: zfs-bootfs: exit-status: matches expectation: 0
Command: zfs-bootfs: stdout: matches expectation: ["resolute/ROOT/resolute"]
Command: zfs-user-home: exit-status: matches expectation: 0
Command: zfs-user-home: stdout: matches expectation: ["/home/packer"]
Command: zfs-rescue-dataset: exit-status: matches expectation: 0
Command: luks-header: exit-status: matches expectation: 0
Command: zfs-user-root: exit-status: matches expectation: 0
Command: zfs-user-root: stdout: matches expectation: ["/root"]
Command: zfs-compression-root: exit-status: matches expectation: 0
Command: zfs-compression-root: stdout: matches expectation: ["lz4"]
Command: zfs-compression-home: exit-status: matches expectation: 0
Command: zfs-compression-home: stdout: matches expectation: ["lz4"]
Command: zfsbootmenu-config: exit-status: matches expectation: 0
Command: luks-crypttab: exit-status: matches expectation: 0
Command: luks-crypttab: stdout: matches expectation: ["root_crypt"]
Package: refind: installed: matches expectation: true
Command: dropbear-in-zfsbootmenu: exit-status: matches expectation: 0
Command: dropbear-in-zfsbootmenu: stdout: matches expectation: ["dropbear"]
Command: refind-config: exit-status: matches expectation: 0
Command: zfs-atime-root: exit-status: matches expectation: 0
Command: zfs-atime-root: stdout: matches expectation: ["off"]
Package: zrepl: installed: matches expectation: true
Package: zfsutils-linux: installed: matches expectation: true
File: /etc/dracut.conf.d/luks_support.conf: exists: matches expectation: true
File: /etc/dracut.conf.d/luks_support.conf: owner: matches expectation: "root"
File: /etc/dracut.conf.d/luks_support.conf: group: matches expectation: "root"
File: /etc/dracut.conf.d/luks_support.conf: contents: matches expectation: ["crypt"]
File: /etc/zrepl/zrepl.yml: exists: matches expectation: true
File: /etc/zrepl/zrepl.yml: owner: matches expectation: "root"
File: /etc/zrepl/zrepl.yml: group: matches expectation: "root"
File: /etc/fstab: exists: matches expectation: true
File: /etc/fstab: owner: matches expectation: "root"
File: /etc/fstab: group: matches expectation: "root"
File: /etc/fstab: contents: matches expectation: ["/boot/efi","vfat"]
File: /root: exists: matches expectation: true
File: /root: owner: matches expectation: "root"
File: /root: group: matches expectation: "root"
File: /root: filetype: matches expectation: "directory"
Service: zrepl: enabled: matches expectation: true
File: /etc/zfs/zroot.lukskey: exists: matches expectation: true
File: /etc/zfs/zroot.lukskey: mode: matches expectation: "0400"
File: /etc/zfs/zroot.lukskey: owner: matches expectation: "root"
File: /etc/zfs/zroot.lukskey: group: matches expectation: "root"
Service: zfs-import-cache: enabled: matches expectation: true
File: /etc/dracut.conf.d/100-zol.conf: exists: matches expectation: true
File: /etc/dracut.conf.d/100-zol.conf: owner: matches expectation: "root"
File: /etc/dracut.conf.d/100-zol.conf: group: matches expectation: "root"
File: /boot/efi/EFI/refind: exists: matches expectation: true
File: /boot/efi/EFI/refind: filetype: matches expectation: "directory"
File: /home/packer: exists: matches expectation: true
File: /home/packer: owner: matches expectation: "packer"
File: /home/packer: group: matches expectation: "packer"
File: /home/packer: filetype: matches expectation: "directory"
File: /etc/zfsbootmenu/dracut.conf.d/zfsbootmenu.conf: exists: matches expectation: true
File: /etc/zfsbootmenu/dracut.conf.d/zfsbootmenu.conf: owner: matches expectation: "root"
File: /etc/zfsbootmenu/dracut.conf.d/zfsbootmenu.conf: group: matches expectation: "root"
File: /etc/zfsbootmenu/dracut.conf.d/zfsbootmenu.conf: contents: matches expectation: ["zfsbootmenu","bash"]
File: /etc/dracut.conf.d/lukskey.conf: exists: matches expectation: true
File: /etc/dracut.conf.d/lukskey.conf: mode: matches expectation: "0644"
File: /etc/dracut.conf.d/lukskey.conf: owner: matches expectation: "root"
File: /etc/dracut.conf.d/lukskey.conf: group: matches expectation: "root"
File: /etc/dracut.conf.d/lukskey.conf: contents: matches expectation: ["zroot.lukskey"]
User: packer: exists: matches expectation: true
User: packer: home: matches expectation: "/home/packer"
User: packer: groups: matches expectation: ["sudo"]
User: root: exists: matches expectation: true
User: root: home: matches expectation: "/root"
File: /etc/zfsbootmenu/dracut.conf.d/dropbear.conf: exists: matches expectation: true
File: /etc/zfsbootmenu/dracut.conf.d/dropbear.conf: owner: matches expectation: "root"
File: /etc/zfsbootmenu/dracut.conf.d/dropbear.conf: group: matches expectation: "root"
File: /etc/zfsbootmenu/dracut.conf.d/dropbear.conf: contents: matches expectation: ["crypt-ssh","dracut-network.conf","dropbear_acl=/home/packer/.ssh/authorized_keys"]
File: /boot/efi/EFI/zfsbootmenu: exists: matches expectation: true
File: /boot/efi/EFI/zfsbootmenu: filetype: matches expectation: "directory"
Package: zfs-dracut: installed: matches expectation: true
Service: zfs-mount: enabled: matches expectation: true


Total Duration: 0.202s
Count: 79, Failed: 0, Skipped: 0

==========================================
[INFO] ✓ All validation tests passed!
==========================================