feat(vm): boot CoreOS via Ignition — Fedora CoreOS now runnable#50
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CoreOS-family images boot via Ignition, not cloud-init, which is why the SSH/cloud-init executor previously marked them unsupported. Add an Ignition seed-delivery mode: write a minimal Ignition v3 config authorising the per-run SSH key for the core user and pass it to QEMU via -fw_cfg name=opt/com.coreos/config (internal/vm/ignition.go). Fedora CoreOS is now runnable and proven end-to-end: FCOS stable boots and the validator load/attaches inside the guest (verified on kernel 7.0.11-200.fc44, ringbuf-modern load=pass attach=1/1). ExecutionTransport reports fedora-coreos supported; the profile is renamed fedora-coreos-stable-7.0 to match the real kernel. Fetch the image with `make vm-image-fcos`. RHEL CoreOS (rhcos) shares this exact Ignition+SSH boot path, so it is mechanically supported — but its image ships only through the pull-secret-gated OpenShift release payload and cannot be fetched/verified here, so it stays non-runnable (transport reason updated) until an operator supplies the image. RHCOS remains absent from the README "Distributions covered" section. Tests: ignition writer/distro-detection/seed-selection/fw_cfg arg + transport matrix; all green. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This was referenced Jun 26, 2026
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Makes the CoreOS boot path real, addressing the "RHCOS — those are the tricky ones" request (Angelo Puglisi) and the earlier audit note that RHCOS validation didn't actually work.
The gap
CoreOS-family images (Fedora CoreOS, RHEL CoreOS) boot via Ignition, not cloud-init, so the SSH/cloud-init executor couldn't provision the validator — they were marked
unsupported.The fix
A new Ignition seed-delivery mode (
internal/vm/ignition.go): write a minimal Ignition v3 config authorising the per-run SSH key for thecoreuser, and pass it to QEMU via-fw_cfg name=opt/com.coreos/config. Everything after SSH-up is seed-agnostic, so the rest of the pipeline is unchanged.Proven on Fedora CoreOS
FCOS stable boots and the validator load + attaches a real artifact inside the guest:
fedora-coreos, kernel7.0.11-200.fc44.x86_64seed delivery: Ignition config via fw_cfg (opt/com.coreos/config),SSH user selected: coreringbuf-modern:load=pass,attach=1/1ExecutionTransport()now reportsfedora-coreossupported. Profile renamedfedora-coreos-stable-6.14→fedora-coreos-stable-7.0to match the real kernel. Fetch the image withmake vm-image-fcos(resolves the stream, verifies sha256, decompresses).RHCOS — honest scope (unchanged claim)
rhcosshares this exact Ignition+SSH boot path, so it is mechanically supported — but its image ships only through the pull-secret-gated OpenShift release payload and can't be fetched/verified here.ExecutionTransport()keeps it unsupported with that precise reason until an operator supplies the image. RHCOS stays absent from the README "Distributions covered" section — no overclaiming.Tests
internal/vm: ignition writer, CoreOS distro detection, seed-mode selection, fw_cfg arg, and the transport matrix (FCOS supported / RHCOS gated-on-image).go build ./...,go vet ./...,gofmt, fullgo test ./...— all green.🤖 Generated with Claude Code