Boot Verification for Bootcrew Nightly CI#

Date: 2026-03-30
Status: Approved

Context#

The bootcrew-nightly.yml workflow installs each matrix image onto a loop device and verifies the resulting partition structure and file layout. It does not verify that the installed system actually boots. A broken GRUB config, corrupt initrd, or bad EFI entry would pass the current checks.

This spec adds a QEMU+OVMF boot step after the existing install verification. It boots the loop device as a full VM and waits for a login prompt on the serial console. Failure to reach a login prompt within the timeout fails the matrix job.

Scope#

One deliverable: modify .github/workflows/bootcrew-nightly.yml to add boot verification after the existing install verification step.

No new files. No changes to fisherman Go code. No changes to bootcrew-fast.yml (that workflow uses fake podman and produces no bootable system).

Design#

Tools#

Add qemu-system-x86 ovmf to the existing sudo apt-get install -y line in the "Install tools" step:

sudo apt-get install -y podman xfsprogs btrfs-progs cryptsetup-bin ostree qemu-system-x86 ovmf

qemu-system-x86 provides qemu-system-x86_64. ovmf provides /usr/share/OVMF/OVMF_CODE.fd.

Boot command#

timeout 180 qemu-system-x86_64 \
  -enable-kvm \
  -m 2G \
  -drive file=$LOOPDEV,format=raw,if=virtio \
  -drive if=pflash,format=raw,readonly=on,file=/usr/share/OVMF/OVMF_CODE.fd \
  -serial stdio \
  -nographic \
  -no-reboot 2>&1 | tee /tmp/boot-$IMAGE_NAME.log

• -enable-kvm: uses hardware virtualisation available on ubuntu-latest runners (/dev/kvm). Without this, boot would be prohibitively slow.
• -m 2G: sufficient RAM for all matrix images to reach login.
• -drive file=$LOOPDEV,format=raw,if=virtio: attaches the installed loop device as a virtio block device. virtio is faster than IDE and is supported by all matrix images.
• -drive if=pflash,...,file=OVMF_CODE.fd: UEFI firmware. Required because the installed system's bootloader is an EFI application.
• -serial stdio -nographic: all serial output goes to stdout, captured by tee.
• -no-reboot: VM halts instead of rebooting on shutdown (prevents infinite boot loops on panic).
• timeout 180: kills QEMU after 3 minutes if login prompt has not appeared.

Success detection#

grep -q "login:" /tmp/boot-$IMAGE_NAME.log

login: appears in the getty prompt on all major Linux distributions (ubuntu-bootc, gnomeos-bootc, opensuse-bootc, yellowfin). If the grep succeeds, the step passes. If timeout fires or the grep finds no match, the step exits non-zero and fails the matrix job.

SELinux#

The boot test boots whatever was installed. No kernel command-line overrides are applied. The existing matrix entry selinux_disabled: true for yellowfin-gnome50 only affects the bootc install flags; it does not affect how the installed system boots.

Timeout#

180 seconds. Expected boot times with KVM:

• yellowfin-gnome50 (ostree/XFS): ~60s
• ubuntu-bootc (composefs-native): ~90s
• gnomeos-bootc (composefs-native): ~90s
• opensuse-bootc (composefs-native): ~90s

180s gives ~2× headroom for runner variance.

Failure behaviour#

Boot failure fails the matrix job. fail-fast: false is already set on the matrix, so other images continue running. The job summary step (already present) reports per-image pass/fail.

Files modified#

Verification#

After implementation, trigger the workflow manually:

gh workflow run bootcrew-nightly.yml

Check that each matrix job shows a "Boot verification" step and that the log contains login:.