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.

```bash
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.

```bash
_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`