add build script

virtual-machines/vm-test/build-image.sh

@@ -0,0 +1,47 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Configuration
+ALIAS="nixos/custom/vm"
+VM_NAME="vmname"
+
+# Build the NixOS LXC metadata tarball
+TARBALL_DIR="$(nix build \
+  ".#nixosConfigurations.${VM_NAME}.config.system.build.metadata" \
+  --print-out-paths)"
+
+# Find the tarball using find -type f
+TARBALL="$(find "$TARBALL_DIR" -type f -name '*.tar.xz' -print -quit)"
+
+if [[ -z "$TARBALL" ]]; then
+    echo "Error: Could not find a .tar.xz tarball in:"
+    echo "  $TARBALL_DIR"
+    exit 1
+fi
+
+echo "Found metadata tarball:"
+echo "  $TARBALL"
+
+# Build the QEMU disk image
+QCOW2="$(nix build \
+  ".#nixosConfigurations.${VM_NAME}.config.system.build.qemuImage" \
+  --print-out-paths)/nixos.qcow2"
+
+if [[ ! -f "$QCOW2" ]]; then
+    echo "Error: QEMU image not found:"
+    echo "  $QCOW2"
+    exit 1
+fi
+
+echo "Importing NixOS image into Incus..."
+echo "  Alias:   $ALIAS"
+echo "  Tarball: $TARBALL"
+echo "  Image:   $QCOW2"
+
+incus image import \
+    --alias "$ALIAS" \
+    "$TARBALL" \
+    "$QCOW2"
+
+echo "Successfully imported image as: $ALIAS"
+