veilor-os/docs/research/2026-05-05-agent-wave/06-anaconda-log-capture.md

Anaconda log capture — virtio-9p host-share

Agent 6 of 9-agent wave, 2026-05-05.

Why current setup is silent

v0.5.30 wired:

-chardev file,id=anaclog,path=$ANACONDA_LOG
-device virtio-serial-pci,id=vs1
-device virtserialport,chardev=anaclog,bus=vs1.0,name=org.fedoraproject.anaconda.log.0

Anaconda is supposed to autodetect this port and stream logs. Result: test/anaconda-vm-*.log files are 0 bytes despite multiple full installs.

Root cause: Anaconda's setupVirtio() (anaconda_logging.py:315) doesn't write to the virtio port directly — it adds a forward rule to /etc/rsyslog.conf then calls restart_service("rsyslog"). No inst.virtiolog boot arg is required (--virtiolog defaults to the right port via argument_parsing.py:512).

The veilor live ISO almost certainly lacks rsyslog (minimal Fedora ks), so the forward rule lands in a file no daemon reads. restart_service is a no-op. The QEMU side opens the port and creates the 0-byte file but nothing ever writes to it.

Even with rsyslog present, only LOG_LOCAL1-tagged messages would flow; the rich content lives in /tmp/anaconda.log, /tmp/program.log, /tmp/storage.log, /tmp/packaging.log which never traverse syslog.

Fix — Option C (virtio-9p host-share + post-install copy)

test/run-vm.sh

Add -virtfs 9p export of test/test-runs/<timestamp>/ tagged hostlogs. Keep existing virtio-serial as belt-and-braces fallback.

TS=$(date +%Y%m%d-%H%M%S)
HOSTLOGS_DIR="$TEST_DIR/test-runs/$TS"
mkdir -p "$HOSTLOGS_DIR"
HOSTSHARE_ARGS=(
    -virtfs "local,path=$HOSTLOGS_DIR,mount_tag=hostlogs,security_model=mapped-xattr,id=hostshare"
)
echo "  Logs  : $HOSTLOGS_DIR"

Append "${HOSTSHARE_ARGS[@]}" \ to the exec qemu-system-x86_64 block.

overlay/usr/local/bin/veilor-installer

In run_install(), install an EXIT trap calling _dump_logs_to_host that mounts the 9p share at /mnt/hostlogs and copies:

• /tmp/{anaconda,program,storage,packaging,dnf,dnf.librepo,anaconda-cmdline}.log
• /var/log/veilor-installer.log
• generated kickstart at /run/install/veilor-generated.ks
• dmesg output
• journalctl -b output

Runs on success, failure, and ^C. Auto-no-ops on real hardware where 9p isn't loaded.

_dump_logs_to_host() {
    if mount -t 9p -o trans=virtio,version=9p2000.L hostlogs /mnt/hostlogs 2>/dev/null; then
        cp -a /tmp/{anaconda,program,storage,packaging,dnf,dnf.librepo,anaconda-cmdline}.log \
              /var/log/veilor-installer.log \
              /run/install/veilor-generated.ks \
              /mnt/hostlogs/ 2>/dev/null || true
        dmesg > /mnt/hostlogs/dmesg.log 2>/dev/null || true
        journalctl -b > /mnt/hostlogs/journal.log 2>/dev/null || true
        umount /mnt/hostlogs 2>/dev/null || true
    fi
}
trap _dump_logs_to_host EXIT

Why options A/B/D were rejected

• A (grub kernel arg surgery — inst.virtiolog) and D (host rsyslog TCP listener with inst.syslog=10.0.2.2:5140) both still rely on rsyslog being present in the live ISO.
• B (anaconda --syslog at CLI) — same dependency.
• C captures complete file-level fidelity regardless. virtio-9p is in the kernel; mount is two lines; copies the actual files.

Files modified

• test/run-vm.sh
• overlay/usr/local/bin/veilor-installer