test(archsetup): add FS_PROFILE selector for ZFS VM coverageHEADmain

The VM harness only built one btrfs base image, so every ZFS-conditional check in the Testinfra suite skipped and the ZFS install path went untested in automation. I added an FS_PROFILE selector (btrfs default, zfs) so `make test FS_PROFILE=zfs` can target a ZFS root.

init_vm_paths derives the image name from FS_PROFILE and validates it. btrfs keeps the legacy unsuffixed archsetup-base.qcow2 so existing images and invocations are untouched. The zfs profile gets archsetup-base-zfs.qcow2. create-base-vm.sh picks archsetup-test.conf vs the new archsetup-test-zfs.conf (FILESYSTEM=zfs, NO_ENCRYPT=yes for an unattended install), and the Makefile resolves the matching image for its base-VM check.

The archsetup run config stays shared. archsetup reads no filesystem key. It detects ZFS from the live root via is_zfs_root, so the ZFS branch fires on its own once the base image is ZFS. The design doc is reconciled to that: no separate archsetup-vm-zfs.conf, and the non-ZFS profile is btrfs, not ext4.

Building the ZFS base image and running the ZFS sweep green is next.

6 files changed, 105 insertions, 19 deletions

diff --git a/Makefile b/Makefile
index a974044..d6e7fa1 100644
--- a/Makefile
+++ b/Makefile
@@ -7,6 +7,17 @@
 
 .PHONY: help deps test-unit test test-keep test-vm-base package-diff
 
+# Filesystem profile for the VM harness: btrfs (default) or zfs. Selects the
+# base image the scripts build/use; exported so create-base-vm.sh + run-test.sh
+# pick the matching archangel config and image. e.g. make test FS_PROFILE=zfs
+FS_PROFILE ?= btrfs
+export FS_PROFILE
+ifeq ($(FS_PROFILE),btrfs)
+BASE_IMAGE := vm-images/archsetup-base.qcow2
+else
+BASE_IMAGE := vm-images/archsetup-base-$(FS_PROFILE).qcow2
+endif
+
 # Default target - show help
 help:
 	@echo "archsetup - install and test"
@@ -19,6 +30,9 @@ help:
 	@echo "  test-vm-base  Create base VM only (runs archangel)"
 	@echo "  package-diff  Compare archsetup's declared packages vs this system"
 	@echo ""
+	@echo "Filesystem profile (test, test-keep, test-vm-base):"
+	@echo "  FS_PROFILE=btrfs (default) or zfs, e.g. make test FS_PROFILE=zfs"
+	@echo ""
 	@echo "Dotfile stow operations now live in the dotfiles repo:"
 	@echo "  cd ~/.dotfiles && make stow|restow|reset|unstow|import <de>"
 	@echo ""
@@ -51,18 +65,18 @@ test-vm-base:
 
 # Test - run full VM integration test suite (creates base VM if needed)
 test:
-	@if [ ! -f vm-images/archsetup-base.qcow2 ] || \
-	   ! qemu-img snapshot -l vm-images/archsetup-base.qcow2 2>/dev/null | grep -q "clean-install"; then \
-		echo "Base VM not found or missing snapshot, creating..."; \
+	@if [ ! -f $(BASE_IMAGE) ] || \
+	   ! qemu-img snapshot -l $(BASE_IMAGE) 2>/dev/null | grep -q "clean-install"; then \
+		echo "Base VM not found or missing snapshot, creating ($(FS_PROFILE))..."; \
 		bash scripts/testing/create-base-vm.sh; \
 	fi
 	@bash scripts/testing/run-test.sh
 
 # Test and keep VM running (for manual testing after archsetup)
 test-keep:
-	@if [ ! -f vm-images/archsetup-base.qcow2 ] || \
-	   ! qemu-img snapshot -l vm-images/archsetup-base.qcow2 2>/dev/null | grep -q "clean-install"; then \
-		echo "Base VM not found or missing snapshot, creating..."; \
+	@if [ ! -f $(BASE_IMAGE) ] || \
+	   ! qemu-img snapshot -l $(BASE_IMAGE) 2>/dev/null | grep -q "clean-install"; then \
+		echo "Base VM not found or missing snapshot, creating ($(FS_PROFILE))..."; \
 		bash scripts/testing/create-base-vm.sh; \
 	fi
 	@bash scripts/testing/run-test.sh --keep
diff --git a/docs/design/2026-06-25-zfs-vm-test-coverage.org b/docs/design/2026-06-25-zfs-vm-test-coverage.org
index 694478f..d9625e0 100644
--- a/docs/design/2026-06-25-zfs-vm-test-coverage.org
+++ b/docs/design/2026-06-25-zfs-vm-test-coverage.org
@@ -70,9 +70,10 @@ test VM (skip the passphrase prompt; encryption isn't what we're validating).
   current/non-ZFS), picks the matching archangel config, and writes a
   profile-named image: =vm-images/archsetup-base.qcow2= (default) vs
   =vm-images/archsetup-base-zfs.qcow2=. Same =clean-install= snapshot name.
-- =run-test.sh= + Makefile take the same =FS_PROFILE= and select the image +
-  the matching archsetup config (=archsetup-vm.conf= vs =archsetup-vm-zfs.conf=,
-  the latter with the ZFS filesystem settings). =make test FS_PROFILE=zfs=.
+- =run-test.sh= + Makefile take the same =FS_PROFILE= and select the image (via
+  =init_vm_paths=). The archsetup run config (=archsetup-vm.conf=) is *shared* —
+  archsetup auto-detects ZFS from the live root, so no per-profile run config is
+  needed. =make test FS_PROFILE=zfs=.
 
 ** C. Bare-metal runner migration
 Mirror the VM runner's fix in =run-test-baremetal.sh=:
@@ -109,12 +110,30 @@ analyze_log_diff, categorize_errors, generate_issue_report, VALIDATION_*.
 - *P-E* delete the dead shell-sweep functions (the standing P5 follow-up).
 
 * Open questions
-1. *Does archangel support a ZFS-root config out of the box?* Verify before P-A;
-   if not, that's its own sub-task (or a feature request to archangel).
-2. *Two images vs one image + two snapshots?* Lean two images — ZFS vs ext4 are
-   different on-disk layouts; cleaner than juggling snapshots on one disk.
-3. *Profile on run-test.sh vs a separate run-test-zfs.sh?* Lean a =FS_PROFILE=
-   param on the existing runner — avoids duplicating the harness.
-4. *Disk size / RAM for the ZFS VM* (ZFS wants more RAM than the 4G default?).
+1. *Does archangel support a ZFS-root config out of the box?* RESOLVED (yes).
+   ZFS is archangel's *default* filesystem (=FILESYSTEM=zfs=, validated by
+   =installer/lib/config.sh:validate_filesystem=), with =NO_ENCRYPT=yes= for an
+   unattended unencrypted install and a ready =installer/velox-zfs.conf.example=
+   to model. No archangel work needed.
+2. *Two images vs one image + two snapshots?* RESOLVED — two images. ZFS vs
+   btrfs are different on-disk layouts; cleaner than juggling snapshots on one
+   disk. =btrfs= keeps the legacy unsuffixed =archsetup-base.qcow2=; =zfs= gets
+   =archsetup-base-zfs.qcow2=.
+3. *Profile on run-test.sh vs a separate run-test-zfs.sh?* RESOLVED —
+   =FS_PROFILE= env param on the existing runner + Makefile, no duplicate
+   harness.
+4. *Disk size / RAM for the ZFS VM* — start at the 4G RAM / 50G disk defaults;
+   bump =VM_RAM= only if the ZFS install OOMs (decide at P-C build time).
 5. *Should the bare-metal runner stay at all once a ZFS VM exists*, or does the
    ZFS VM profile make it redundant for everything except real-hardware smoke?
+   Defer until after P-D.
+
+* Design corrections (found during P-A/P-B grounding)
+- The "non-ZFS" base is *btrfs*, not ext4 — =archsetup-test.conf= sets
+  =FILESYSTEM=btrfs=. The profile axis is zfs vs btrfs throughout.
+- *No =archsetup-vm-zfs.conf= is needed.* archsetup reads no filesystem key; it
+  auto-detects ZFS from the live root via =is_zfs_root()= (=findmnt -n -o FSTYPE
+  /=, archsetup:688). The ZFS branch (sanoid, zfs-scrub timer, mkinitcpio udev
+  hook, docker zfs storage driver) fires whenever the running root is ZFS. So
+  only the *archangel* base config and the base *image* differ per profile; the
+  archsetup run config (=archsetup-vm.conf=) is shared.
diff --git a/scripts/testing/archsetup-test-zfs.conf b/scripts/testing/archsetup-test-zfs.conf
new file mode 100644
index 0000000..a5459cf
--- /dev/null
+++ b/scripts/testing/archsetup-test-zfs.conf
@@ -0,0 +1,21 @@
+# archsetup-test-zfs.conf - Archangel config for archsetup ZFS test VMs
+# Used by create-base-vm.sh (FS_PROFILE=zfs) for fully automated base VM creation
+#
+# Usage: archangel --config-file /root/archsetup-test.conf
+#
+# Note: User creation is handled by archsetup, not archangel.
+# See archsetup-vm.conf for archsetup configuration (shared across profiles -
+# archsetup detects ZFS from the live root, so it needs no filesystem setting).
+#
+# Unencrypted ZFS root: encryption isn't what the harness validates, and
+# NO_ENCRYPT=yes skips the passphrase prompt for a fully unattended install.
+
+FILESYSTEM=zfs
+HOSTNAME=archsetup-test
+TIMEZONE=America/Chicago
+LOCALE=en_US.UTF-8
+KEYMAP=us
+DISKS=/dev/vda
+NO_ENCRYPT=yes
+ROOT_PASSWORD=archsetup
+ENABLE_SSH=yes
diff --git a/scripts/testing/create-base-vm.sh b/scripts/testing/create-base-vm.sh
index b8a4e2b..e626813 100755
--- a/scripts/testing/create-base-vm.sh
+++ b/scripts/testing/create-base-vm.sh
@@ -20,10 +20,19 @@ source "$SCRIPT_DIR/lib/vm-utils.sh"
 
 # Configuration
 VM_IMAGES_DIR="$PROJECT_ROOT/vm-images"
-CONFIG_FILE="$SCRIPT_DIR/archsetup-test.conf"
 LIVE_ISO_PASSWORD="archangel"
 SNAPSHOT_NAME="clean-install"
 
+# FS_PROFILE (btrfs default / zfs) picks the archangel base-install config.
+# btrfs -> archsetup-test.conf, zfs -> archsetup-test-zfs.conf. The matching
+# base image name is derived from FS_PROFILE by init_vm_paths.
+FS_PROFILE="${FS_PROFILE:-btrfs}"
+if [ "$FS_PROFILE" = "btrfs" ]; then
+    CONFIG_FILE="$SCRIPT_DIR/archsetup-test.conf"
+else
+    CONFIG_FILE="$SCRIPT_DIR/archsetup-test-${FS_PROFILE}.conf"
+fi
+
 # Initialize logging
 mkdir -p "$PROJECT_ROOT/test-results"
 LOGFILE="$PROJECT_ROOT/test-results/create-base-vm-$(date +'%Y%m%d-%H%M%S').log"
diff --git a/scripts/testing/lib/vm-utils.sh b/scripts/testing/lib/vm-utils.sh
index f86e583..6d9f6f6 100755
--- a/scripts/testing/lib/vm-utils.sh
+++ b/scripts/testing/lib/vm-utils.sh
@@ -14,6 +14,12 @@ VM_CPUS="${VM_CPUS:-4}"
 VM_RAM="${VM_RAM:-4096}"  # MB
 VM_DISK_SIZE="${VM_DISK_SIZE:-50}"  # GB
 
+# Filesystem profile: selects which base image + archangel config the harness
+# targets. "btrfs" is the historical default (its image name stays unsuffixed
+# so existing base images keep working); "zfs" gets its own image, since the
+# two on-disk layouts can't share a disk. Honoured by init_vm_paths below.
+FS_PROFILE="${FS_PROFILE:-btrfs}"
+
 # SSH configuration
 SSH_PORT="${SSH_PORT:-2222}"
 SSH_OPTS="-o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o ConnectTimeout=10"
@@ -42,8 +48,17 @@ init_vm_paths() {
     local images_dir="${1:-$VM_IMAGES_DIR}"
     [ -z "$images_dir" ] && fatal "VM_IMAGES_DIR not set"
 
+    case "$FS_PROFILE" in
+        btrfs|zfs) ;;
+        *) fatal "Invalid FS_PROFILE: $FS_PROFILE (must be 'btrfs' or 'zfs')" ;;
+    esac
+
     VM_IMAGES_DIR="$images_dir"
-    DISK_PATH="$VM_IMAGES_DIR/archsetup-base.qcow2"
+    # btrfs keeps the legacy unsuffixed name; other profiles get a suffix so
+    # their images sit side by side without clobbering each other.
+    local img_suffix=""
+    [ "$FS_PROFILE" != "btrfs" ] && img_suffix="-$FS_PROFILE"
+    DISK_PATH="$VM_IMAGES_DIR/archsetup-base${img_suffix}.qcow2"
     OVMF_VARS="$VM_IMAGES_DIR/OVMF_VARS.fd"
     PID_FILE="$VM_IMAGES_DIR/qemu.pid"
     MONITOR_SOCK="$VM_IMAGES_DIR/qemu-monitor.sock"
diff --git a/scripts/testing/run-test.sh b/scripts/testing/run-test.sh
index a22ae98..f962df3 100755
--- a/scripts/testing/run-test.sh
+++ b/scripts/testing/run-test.sh
@@ -50,6 +50,9 @@ while [[ $# -gt 0 ]]; do
             echo "  --keep      Keep VM in post-test state (for debugging)"
             echo "  --script    Specify custom archsetup script to test"
             echo "  --snapshot  Snapshot name to revert to (default: clean-install)"
+            echo ""
+            echo "Env: FS_PROFILE=btrfs|zfs (default btrfs) selects the base image"
+            echo "     built by create-base-vm.sh. e.g. FS_PROFILE=zfs $0"
             exit 1
             ;;
     esac
@@ -100,6 +103,7 @@ init_logging "$LOGFILE"
 init_vm_paths "$VM_IMAGES_DIR"
 
 section "ArchSetup Test Run: $TIMESTAMP"
+info "Filesystem profile: $FS_PROFILE (image: $(basename "$DISK_PATH"))"
 
 # Verify archsetup script exists
 if [ ! -f "$ARCHSETUP_SCRIPT" ]; then
@@ -108,7 +112,11 @@ fi
 
 # Check disk exists
 if [ ! -f "$DISK_PATH" ]; then
-    info "Create it first: ./scripts/testing/create-base-vm.sh"
+    if [ "$FS_PROFILE" = "btrfs" ]; then
+        info "Create it first: ./scripts/testing/create-base-vm.sh"
+    else
+        info "Create it first: FS_PROFILE=$FS_PROFILE ./scripts/testing/create-base-vm.sh"
+    fi
     fatal "Base disk not found: $DISK_PATH"
 fi