Make installed banger self-contained

Fix the misleading make install path where banger and bangerd still depended on a repo checkout for Firecracker, guest artifacts, image builds, and the SSH key.

Replace repo-root inference with an explicit runtime bundle model: resolve a runtime_dir from env/config/install layout, derive concrete artifact paths from it, and update the daemon, CLI, and image-build flow to use those paths. Keep repo_root only as an explicit compatibility alias instead of auto-detecting it.

Teach customize.sh to run from a read-only bundled runtime tree while writing transient state under XDG/BANGER_STATE_DIR, and make make install copy the runtime assets into PREFIX/lib/banger so installed binaries stay usable outside the repo.

Validate with go test ./..., make build, bash -n customize.sh, and make install DESTDIR=/tmp/banger-install PREFIX=/usr. An out-of-repo installed-binary smoke test was attempted, but this sandbox blocked bangerd from binding its Unix socket (setsockopt: operation not permitted).

Makefile

@@ -5,9 +5,15 @@ GOFMT ?= gofmt
 INSTALL ?= install
 PREFIX ?= $(HOME)/.local
 BINDIR ?= $(PREFIX)/bin
+LIBDIR ?= $(PREFIX)/lib
+RUNTIMEDIR ?= $(LIBDIR)/banger
 DESTDIR ?=
 BINARIES := banger bangerd
 GO_SOURCES := $(shell find cmd internal -type f -name '*.go' | sort)
+RUNTIME_EXECUTABLES := firecracker customize.sh dns.sh packages.sh nat.sh namegen
+RUNTIME_DATA_FILES := packages.apt $(wildcard rootfs.ext4) $(wildcard rootfs-docker.ext4)
+RUNTIME_BOOT_FILES := wtf/root/boot/vmlinux-6.8.0-94-generic wtf/root/boot/initrd.img-6.8.0-94-generic
+RUNTIME_MODULES_DIR := wtf/root/lib/modules/6.8.0-94-generic
 
 .DEFAULT_GOAL := help
 
@@ -17,12 +23,12 @@ help:
 	@printf '%s\n' \
 	  'Targets:' \
 	  '  make build   Build ./banger and ./bangerd' \
-	  '  make install Build and install binaries into $(DESTDIR)$(BINDIR)' \
+	  '  make install Build and install binaries plus the runtime bundle into $(DESTDIR)$(BINDIR) and $(DESTDIR)$(RUNTIMEDIR)' \
 	  '  make test    Run go test ./...' \
 	  '  make fmt     Format Go sources under cmd/ and internal/' \
 	  '  make tidy    Run go mod tidy' \
 	  '  make clean   Remove built Go binaries' \
-	  '  make rootfs  Run ./make-rootfs.sh'
+	  '  make rootfs  Rebuild the repo-local default rootfs image'
 
 build: $(BINARIES)
 
@@ -45,9 +51,24 @@ clean:
 	rm -f ./banger ./bangerd
 
 install: build
+	@for path in $(RUNTIME_EXECUTABLES) $(RUNTIME_BOOT_FILES) $(RUNTIME_MODULES_DIR) packages.apt id_ed25519; do \
+		test -e "$$path" || { echo "missing runtime artifact: $$path" >&2; exit 1; }; \
+	done
+	@test -e rootfs-docker.ext4 || test -e rootfs.ext4 || { echo "missing runtime artifact: rootfs-docker.ext4 or rootfs.ext4" >&2; exit 1; }
 	mkdir -p "$(DESTDIR)$(BINDIR)"
+	mkdir -p "$(DESTDIR)$(RUNTIMEDIR)"
+	mkdir -p "$(DESTDIR)$(RUNTIMEDIR)/wtf/root/boot"
+	mkdir -p "$(DESTDIR)$(RUNTIMEDIR)/wtf/root/lib/modules"
 	$(INSTALL) -m 0755 ./banger "$(DESTDIR)$(BINDIR)/banger"
 	$(INSTALL) -m 0755 ./bangerd "$(DESTDIR)$(BINDIR)/bangerd"
+	@for path in $(RUNTIME_EXECUTABLES); do \
+		$(INSTALL) -m 0755 "$$path" "$(DESTDIR)$(RUNTIMEDIR)/$$path"; \
+	done
+	@for path in $(RUNTIME_DATA_FILES) $(RUNTIME_BOOT_FILES); do \
+		$(INSTALL) -m 0644 "$$path" "$(DESTDIR)$(RUNTIMEDIR)/$$path"; \
+	done
+	$(INSTALL) -m 0600 id_ed25519 "$(DESTDIR)$(RUNTIMEDIR)/id_ed25519"
+	cp -a "$(RUNTIME_MODULES_DIR)" "$(DESTDIR)$(RUNTIMEDIR)/wtf/root/lib/modules/"
 
 rootfs:
 	./make-rootfs.sh

customize.sh

@@ -29,19 +29,20 @@ parse_size() {
   return 1
 }
 
-DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+RUNTIME_DIR="${BANGER_RUNTIME_DIR:-$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)}"
-source "$DIR/dns.sh"
+source "$RUNTIME_DIR/dns.sh"
-source "$DIR/packages.sh"
+source "$RUNTIME_DIR/packages.sh"
-STATE="$DIR/state"
+STATE="${BANGER_STATE_DIR:-${XDG_STATE_HOME:-$HOME/.local/state}/banger/image-build}"
 VM_ROOT="$STATE/vms"
 mkdir -p "$VM_ROOT"
 
-BASE_ROOTFS="$DIR/rootfs.ext4"
+BASE_ROOTFS="$RUNTIME_DIR/rootfs.ext4"
-FC_BIN="$DIR/firecracker"
+FC_BIN="$RUNTIME_DIR/firecracker"
 
-KERNEL="$DIR/wtf/root/boot/vmlinux-6.8.0-94-generic"
+KERNEL="$RUNTIME_DIR/wtf/root/boot/vmlinux-6.8.0-94-generic"
-INITRD="$DIR/wtf/root/boot/initrd.img-6.8.0-94-generic"
+INITRD="$RUNTIME_DIR/wtf/root/boot/initrd.img-6.8.0-94-generic"
-SSH_KEY="$DIR/id_ed25519"
+SSH_KEY="$RUNTIME_DIR/id_ed25519"
+NAT_SCRIPT="$RUNTIME_DIR/nat.sh"
 
 BR_DEV="br-fc"
 BR_IP="172.16.0.1"
@@ -52,7 +53,7 @@ BASE_ROOTFS=""
 OUT_ROOTFS=""
 SIZE_SPEC=""
 INSTALL_DOCKER=0
-MODULES_DIR="$DIR/wtf/root/lib/modules/6.8.0-94-generic"
+MODULES_DIR="$RUNTIME_DIR/wtf/root/lib/modules/6.8.0-94-generic"
 PACKAGES_FILE="$(banger_packages_file)"
 while [[ $# -gt 0 ]]; do
   case "$1" in
@@ -304,7 +305,7 @@ jq -n \
   > "$VM_DIR/vm.json"
 
 log "enabling NAT for customization"
-sudo -E ./nat.sh up "$VM_TAG" >/dev/null
+sudo -E "$NAT_SCRIPT" up "$VM_TAG" >/dev/null
 
 log "waiting for SSH"
 SSH_READY=0

internal/cli/banger.go

@@ -131,6 +131,7 @@ func newVMCommand() *cobra.Command {
 	return cmd
 }
 
+
 func newVMCreateCommand() *cobra.Command {
 	var params api.VMCreateParams
 	cmd := &cobra.Command{
@@ -372,6 +373,9 @@ func newImageBuildCommand() *cobra.Command {
 		Short: "Build an image",
 		Args:  noArgsUsage("usage: banger image build"),
 		RunE: func(cmd *cobra.Command, args []string) error {
+			if err := absolutizeImageBuildPaths(&params); err != nil {
+				return err
+			}
 			if err := system.EnsureSudo(cmd.Context()); err != nil {
 				return err
 			}
@@ -631,14 +635,28 @@ func sshCommandArgs(cfg model.DaemonConfig, guestIP string, extra []string) ([]s
 		return nil, errors.New("vm has no guest IP")
 	}
 	args := []string{}
-	if cfg.RepoRoot != "" {
+	if cfg.SSHKeyPath != "" {
-		args = append(args, "-i", filepath.Join(cfg.RepoRoot, "id_ed25519"))
+		args = append(args, "-i", cfg.SSHKeyPath)
 	}
 	args = append(args, "-o", "StrictHostKeyChecking=no", "-o", "UserKnownHostsFile=/dev/null", "root@"+guestIP)
 	args = append(args, extra...)
 	return args, nil
 }
 
+func absolutizeImageBuildPaths(params *api.ImageBuildParams) error {
+	var err error
+	for _, value := range []*string{&params.BaseRootfs, &params.KernelPath, &params.InitrdPath, &params.ModulesDir} {
+		if *value == "" || filepath.IsAbs(*value) {
+			continue
+		}
+		*value, err = filepath.Abs(*value)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func printJSON(out anyWriter, v any) error {
 	data, err := json.MarshalIndent(v, "", "  ")
 	if err != nil {

internal/cli/cli_test.go

@@ -6,6 +6,7 @@ import (
 	"reflect"
 	"testing"
 
+	"banger/internal/api"
 	"banger/internal/model"
 )
 
@@ -38,6 +39,7 @@ func TestVMCreateFlagsExist(t *testing.T) {
 	}
 }
 
+
 func TestVMSetParamsFromFlags(t *testing.T) {
 	params, err := vmSetParamsFromFlags("devbox", 4, 2048, "16G", true, false)
 	if err != nil {
@@ -64,12 +66,12 @@ func TestVMSetParamsFromFlagsConflict(t *testing.T) {
 }
 
 func TestSSHCommandArgs(t *testing.T) {
-	args, err := sshCommandArgs(model.DaemonConfig{RepoRoot: "/repo"}, "172.16.0.2", []string{"--", "uname", "-a"})
+	args, err := sshCommandArgs(model.DaemonConfig{SSHKeyPath: "/bundle/id_ed25519"}, "172.16.0.2", []string{"--", "uname", "-a"})
 	if err != nil {
 		t.Fatalf("sshCommandArgs: %v", err)
 	}
 	want := []string{
-		"-i", "/repo/id_ed25519",
+		"-i", "/bundle/id_ed25519",
 		"-o", "StrictHostKeyChecking=no",
 		"-o", "UserKnownHostsFile=/dev/null",
 		"root@172.16.0.2",
@@ -127,3 +129,37 @@ func TestDaemonOutdated(t *testing.T) {
 		t.Fatal("expected replaced daemon executable to be outdated")
 	}
 }
+
+func TestAbsolutizeImageBuildPaths(t *testing.T) {
+	dir := t.TempDir()
+	prev, err := os.Getwd()
+	if err != nil {
+		t.Fatalf("getwd: %v", err)
+	}
+	if err := os.Chdir(dir); err != nil {
+		t.Fatalf("chdir: %v", err)
+	}
+	t.Cleanup(func() {
+		_ = os.Chdir(prev)
+	})
+
+	params := api.ImageBuildParams{
+		BaseRootfs: "images/base.ext4",
+		KernelPath: "/kernel",
+		InitrdPath: "boot/initrd.img",
+		ModulesDir: "modules",
+	}
+	if err := absolutizeImageBuildPaths(&params); err != nil {
+		t.Fatalf("absolutizeImageBuildPaths: %v", err)
+	}
+
+	want := api.ImageBuildParams{
+		BaseRootfs: filepath.Join(dir, "images/base.ext4"),
+		KernelPath: "/kernel",
+		InitrdPath: filepath.Join(dir, "boot/initrd.img"),
+		ModulesDir: filepath.Join(dir, "modules"),
+	}
+	if !reflect.DeepEqual(params, want) {
+		t.Fatalf("params = %+v, want %+v", params, want)
+	}
+}

internal/config/config.go

@@ -12,8 +12,14 @@ import (
 )
 
 type fileConfig struct {
+	RuntimeDir         string `toml:"runtime_dir"`
 	RepoRoot           string `toml:"repo_root"`
+	FirecrackerBin     string `toml:"firecracker_bin"`
+	SSHKeyPath         string `toml:"ssh_key_path"`
+	NamegenPath        string `toml:"namegen_path"`
+	CustomizeScript    string `toml:"customize_script"`
 	DefaultImageName   string `toml:"default_image_name"`
+	DefaultRootfs      string `toml:"default_rootfs"`
 	DefaultBaseRootfs  string `toml:"default_base_rootfs"`
 	DefaultKernel      string `toml:"default_kernel"`
 	DefaultInitrd      string `toml:"default_initrd"`
@@ -30,7 +36,6 @@ type fileConfig struct {
 
 func Load(layout paths.Layout) (model.DaemonConfig, error) {
 	cfg := model.DaemonConfig{
-		RepoRoot:            paths.DetectRepoRoot(),
 		AutoStopStaleAfter:  0,
 		StatsPollInterval:   model.DefaultStatsPollInterval,
 		MetricsPollInterval: model.DefaultMetricsPollInterval,
@@ -40,39 +45,45 @@ func Load(layout paths.Layout) (model.DaemonConfig, error) {
 		DefaultDNS:          model.DefaultDNS,
 		DefaultImageName:    "default",
 	}
-	if cfg.RepoRoot != "" {
-		cfg.DefaultBaseRootfs = filepath.Join(cfg.RepoRoot, "rootfs.ext4")
-		cfg.DefaultKernel = filepath.Join(cfg.RepoRoot, "wtf/root/boot/vmlinux-6.8.0-94-generic")
-		cfg.DefaultInitrd = filepath.Join(cfg.RepoRoot, "wtf/root/boot/initrd.img-6.8.0-94-generic")
-		cfg.DefaultModulesDir = filepath.Join(cfg.RepoRoot, "wtf/root/lib/modules/6.8.0-94-generic")
-		cfg.DefaultPackagesFile = filepath.Join(cfg.RepoRoot, "packages.apt")
-	}
 
 	path := filepath.Join(layout.ConfigDir, "config.toml")
 	info, err := os.Stat(path)
-	if err != nil {
-		if os.IsNotExist(err) {
-			return cfg, nil
-		}
-		return cfg, err
-	}
-	if info.IsDir() {
-		return cfg, nil
-	}
-	data, err := os.ReadFile(path)
-	if err != nil {
-		return cfg, err
-	}
 	var file fileConfig
-	if err := toml.Unmarshal(data, &file); err != nil {
+	if err != nil {
-		return cfg, err
+		if !os.IsNotExist(err) {
+			return cfg, err
+		}
+	} else if !info.IsDir() {
+		data, err := os.ReadFile(path)
+		if err != nil {
+			return cfg, err
+		}
+		if err := toml.Unmarshal(data, &file); err != nil {
+			return cfg, err
+		}
 	}
-	if file.RepoRoot != "" {
+
-		cfg.RepoRoot = file.RepoRoot
+	cfg.RuntimeDir = paths.ResolveRuntimeDir(file.RuntimeDir, file.RepoRoot)
+	applyRuntimeDefaults(&cfg)
+
+	if file.FirecrackerBin != "" {
+		cfg.FirecrackerBin = file.FirecrackerBin
+	}
+	if file.SSHKeyPath != "" {
+		cfg.SSHKeyPath = file.SSHKeyPath
+	}
+	if file.NamegenPath != "" {
+		cfg.NamegenPath = file.NamegenPath
+	}
+	if file.CustomizeScript != "" {
+		cfg.CustomizeScript = file.CustomizeScript
 	}
 	if file.DefaultImageName != "" {
 		cfg.DefaultImageName = file.DefaultImageName
 	}
+	if file.DefaultRootfs != "" {
+		cfg.DefaultRootfs = file.DefaultRootfs
+	}
 	if file.DefaultBaseRootfs != "" {
 		cfg.DefaultBaseRootfs = file.DefaultBaseRootfs
 	}
@@ -123,3 +134,48 @@ func Load(layout paths.Layout) (model.DaemonConfig, error) {
 	}
 	return cfg, nil
 }
+
+func applyRuntimeDefaults(cfg *model.DaemonConfig) {
+	if cfg.RuntimeDir == "" {
+		return
+	}
+	cfg.FirecrackerBin = defaultRuntimePath(cfg.FirecrackerBin, cfg.RuntimeDir, "firecracker")
+	cfg.SSHKeyPath = defaultRuntimePath(cfg.SSHKeyPath, cfg.RuntimeDir, "id_ed25519")
+	cfg.NamegenPath = defaultRuntimePath(cfg.NamegenPath, cfg.RuntimeDir, "namegen")
+	cfg.CustomizeScript = defaultRuntimePath(cfg.CustomizeScript, cfg.RuntimeDir, "customize.sh")
+	cfg.DefaultKernel = defaultRuntimePath(cfg.DefaultKernel, cfg.RuntimeDir, "wtf/root/boot/vmlinux-6.8.0-94-generic")
+	cfg.DefaultInitrd = defaultRuntimePath(cfg.DefaultInitrd, cfg.RuntimeDir, "wtf/root/boot/initrd.img-6.8.0-94-generic")
+	cfg.DefaultModulesDir = defaultRuntimePath(cfg.DefaultModulesDir, cfg.RuntimeDir, "wtf/root/lib/modules/6.8.0-94-generic")
+	cfg.DefaultPackagesFile = defaultRuntimePath(cfg.DefaultPackagesFile, cfg.RuntimeDir, "packages.apt")
+	if cfg.DefaultRootfs == "" {
+		cfg.DefaultRootfs = firstExistingRuntimePath(
+			filepath.Join(cfg.RuntimeDir, "rootfs-docker.ext4"),
+			filepath.Join(cfg.RuntimeDir, "rootfs.ext4"),
+		)
+	}
+	if cfg.DefaultBaseRootfs == "" {
+		cfg.DefaultBaseRootfs = firstExistingRuntimePath(
+			filepath.Join(cfg.RuntimeDir, "rootfs.ext4"),
+			cfg.DefaultRootfs,
+		)
+	}
+}
+
+func defaultRuntimePath(current, runtimeDir, relative string) string {
+	if current != "" {
+		return current
+	}
+	return filepath.Join(runtimeDir, relative)
+}
+
+func firstExistingRuntimePath(paths ...string) string {
+	for _, candidate := range paths {
+		if candidate == "" {
+			continue
+		}
+		if _, err := os.Stat(candidate); err == nil {
+			return candidate
+		}
+	}
+	return ""
+}

internal/config/config_test.go

@@ -0,0 +1,72 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"banger/internal/paths"
+)
+
+func TestLoadDerivesArtifactPathsFromRuntimeDir(t *testing.T) {
+	runtimeDir := t.TempDir()
+	for _, rel := range []string{
+		"firecracker",
+		"id_ed25519",
+		"namegen",
+		"customize.sh",
+		"packages.apt",
+		"rootfs-docker.ext4",
+		"wtf/root/boot/vmlinux-6.8.0-94-generic",
+		"wtf/root/boot/initrd.img-6.8.0-94-generic",
+		"wtf/root/lib/modules/6.8.0-94-generic/modules.dep",
+	} {
+		path := filepath.Join(runtimeDir, rel)
+		if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
+			t.Fatalf("mkdir %s: %v", filepath.Dir(path), err)
+		}
+		if err := os.WriteFile(path, []byte("test"), 0o644); err != nil {
+			t.Fatalf("write %s: %v", path, err)
+		}
+	}
+
+	t.Setenv("BANGER_RUNTIME_DIR", runtimeDir)
+	cfg, err := Load(paths.Layout{ConfigDir: t.TempDir()})
+	if err != nil {
+		t.Fatalf("Load: %v", err)
+	}
+
+	if cfg.RuntimeDir != runtimeDir {
+		t.Fatalf("RuntimeDir = %q, want %q", cfg.RuntimeDir, runtimeDir)
+	}
+	if cfg.FirecrackerBin != filepath.Join(runtimeDir, "firecracker") {
+		t.Fatalf("FirecrackerBin = %q", cfg.FirecrackerBin)
+	}
+	if cfg.SSHKeyPath != filepath.Join(runtimeDir, "id_ed25519") {
+		t.Fatalf("SSHKeyPath = %q", cfg.SSHKeyPath)
+	}
+	if cfg.NamegenPath != filepath.Join(runtimeDir, "namegen") {
+		t.Fatalf("NamegenPath = %q", cfg.NamegenPath)
+	}
+	if cfg.CustomizeScript != filepath.Join(runtimeDir, "customize.sh") {
+		t.Fatalf("CustomizeScript = %q", cfg.CustomizeScript)
+	}
+	if cfg.DefaultRootfs != filepath.Join(runtimeDir, "rootfs-docker.ext4") {
+		t.Fatalf("DefaultRootfs = %q", cfg.DefaultRootfs)
+	}
+	if cfg.DefaultBaseRootfs != filepath.Join(runtimeDir, "rootfs-docker.ext4") {
+		t.Fatalf("DefaultBaseRootfs = %q", cfg.DefaultBaseRootfs)
+	}
+	if cfg.DefaultKernel != filepath.Join(runtimeDir, "wtf/root/boot/vmlinux-6.8.0-94-generic") {
+		t.Fatalf("DefaultKernel = %q", cfg.DefaultKernel)
+	}
+	if cfg.DefaultInitrd != filepath.Join(runtimeDir, "wtf/root/boot/initrd.img-6.8.0-94-generic") {
+		t.Fatalf("DefaultInitrd = %q", cfg.DefaultInitrd)
+	}
+	if cfg.DefaultModulesDir != filepath.Join(runtimeDir, "wtf/root/lib/modules/6.8.0-94-generic") {
+		t.Fatalf("DefaultModulesDir = %q", cfg.DefaultModulesDir)
+	}
+	if cfg.DefaultPackagesFile != filepath.Join(runtimeDir, "packages.apt") {
+		t.Fatalf("DefaultPackagesFile = %q", cfg.DefaultPackagesFile)
+	}
+}

internal/daemon/daemon.go

@@ -267,13 +267,13 @@ func (d *Daemon) backgroundLoop() {
 }
 
 func (d *Daemon) ensureDefaultImage(ctx context.Context) error {
-	if d.config.DefaultImageName == "" || d.config.RepoRoot == "" {
+	if d.config.DefaultImageName == "" {
 		return nil
 	}
 	if _, err := d.store.GetImageByName(ctx, d.config.DefaultImageName); err == nil {
 		return nil
 	}
-	rootfs := filepath.Join(d.config.RepoRoot, "rootfs-docker.ext4")
+	rootfs := d.config.DefaultRootfs
 	kernel := d.config.DefaultKernel
 	initrd := d.config.DefaultInitrd
 	if !exists(rootfs) || !exists(kernel) {

internal/daemon/daemon_test.go

@@ -0,0 +1,54 @@
+package daemon
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"banger/internal/model"
+	"banger/internal/store"
+)
+
+func TestEnsureDefaultImageUsesConfiguredDefaultRootfs(t *testing.T) {
+	dir := t.TempDir()
+	rootfs := filepath.Join(dir, "rootfs-docker.ext4")
+	kernel := filepath.Join(dir, "vmlinux")
+	for _, path := range []string{rootfs, kernel} {
+		if err := os.WriteFile(path, []byte("test"), 0o644); err != nil {
+			t.Fatalf("write %s: %v", path, err)
+		}
+	}
+
+	db, err := store.Open(filepath.Join(dir, "state.db"))
+	if err != nil {
+		t.Fatalf("open store: %v", err)
+	}
+	t.Cleanup(func() {
+		_ = db.Close()
+	})
+
+	d := &Daemon{
+		config: model.DaemonConfig{
+			DefaultImageName: "default",
+			DefaultRootfs:    rootfs,
+			DefaultKernel:    kernel,
+		},
+		store: db,
+	}
+
+	if err := d.ensureDefaultImage(context.Background()); err != nil {
+		t.Fatalf("ensureDefaultImage: %v", err)
+	}
+
+	image, err := db.GetImageByName(context.Background(), "default")
+	if err != nil {
+		t.Fatalf("GetImageByName: %v", err)
+	}
+	if image.RootfsPath != rootfs {
+		t.Fatalf("RootfsPath = %q, want %q", image.RootfsPath, rootfs)
+	}
+	if image.KernelPath != kernel {
+		t.Fatalf("KernelPath = %q, want %q", image.KernelPath, kernel)
+	}
+}

internal/daemon/images.go

@@ -22,9 +22,6 @@ func (d *Daemon) BuildImage(ctx context.Context, params api.ImageBuildParams) (m
 	if _, err := d.FindImage(ctx, name); err == nil {
 		return model.Image{}, fmt.Errorf("image name already exists: %s", name)
 	}
-	if d.config.RepoRoot == "" {
-		return model.Image{}, fmt.Errorf("repo root not found; set repo_root in config.toml")
-	}
 	baseRootfs := params.BaseRootfs
 	if baseRootfs == "" {
 		baseRootfs = d.config.DefaultBaseRootfs
@@ -42,7 +39,10 @@ func (d *Daemon) BuildImage(ctx context.Context, params api.ImageBuildParams) (m
 		return model.Image{}, err
 	}
 	rootfsPath := filepath.Join(artifactDir, "rootfs.ext4")
-	script := filepath.Join(d.config.RepoRoot, "customize.sh")
+	script := d.config.CustomizeScript
+	if script == "" {
+		return model.Image{}, fmt.Errorf("customize script not configured; set runtime_dir or customize_script in config.toml")
+	}
 	if _, err := os.Stat(script); err != nil {
 		return model.Image{}, fmt.Errorf("customize.sh not found at %s", script)
 	}
@@ -78,7 +78,12 @@ func (d *Daemon) BuildImage(ctx context.Context, params api.ImageBuildParams) (m
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
 	cmd.Stdin = os.Stdin
-	cmd.Dir = d.config.RepoRoot
+	cmd.Dir = d.layout.StateDir
+	cmd.Env = append(
+		os.Environ(),
+		"BANGER_RUNTIME_DIR="+d.config.RuntimeDir,
+		"BANGER_STATE_DIR="+filepath.Join(d.layout.StateDir, "image-build"),
+	)
 	if err := cmd.Run(); err != nil {
 		_ = os.RemoveAll(artifactDir)
 		return model.Image{}, err

internal/daemon/vm.go

@@ -546,10 +546,10 @@ func (d *Daemon) createTap(ctx context.Context, tap string) error {
 }
 
 func (d *Daemon) firecrackerBinary() (string, error) {
-	if d.config.RepoRoot == "" {
+	if d.config.FirecrackerBin == "" {
-		return "", errors.New("repo root not detected")
+		return "", errors.New("firecracker binary not configured; set runtime_dir or firecracker_bin in config.toml")
 	}
-	path := filepath.Join(d.config.RepoRoot, "firecracker")
+	path := d.config.FirecrackerBin
 	if !exists(path) {
 		return "", fmt.Errorf("firecracker binary not found at %s", path)
 	}
@@ -689,15 +689,12 @@ func (d *Daemon) requireStartPrereqs(ctx context.Context) error {
 }
 
 func (d *Daemon) generateName(ctx context.Context) (string, error) {
-	if d.config.RepoRoot != "" {
+	if exists(d.config.NamegenPath) {
-		namegen := filepath.Join(d.config.RepoRoot, "namegen")
+		out, err := d.runner.Run(ctx, d.config.NamegenPath)
-		if exists(namegen) {
+		if err == nil {
-			out, err := d.runner.Run(ctx, namegen)
+			name := strings.TrimSpace(string(out))
-			if err == nil {
+			if name != "" {
-				name := strings.TrimSpace(string(out))
+				return name, nil
-				if name != "" {
-					return name, nil
-				}
 			}
 		}
 	}

internal/model/types.go

@@ -35,7 +35,11 @@ const (
 )
 
 type DaemonConfig struct {
-	RepoRoot            string
+	RuntimeDir          string
+	FirecrackerBin      string
+	SSHKeyPath          string
+	NamegenPath         string
+	CustomizeScript     string
 	AutoStopStaleAfter  time.Duration
 	StatsPollInterval   time.Duration
 	MetricsPollInterval time.Duration
@@ -44,6 +48,7 @@ type DaemonConfig struct {
 	CIDR                string
 	DefaultDNS          string
 	DefaultImageName    string
+	DefaultRootfs       string
 	DefaultBaseRootfs   string
 	DefaultKernel       string
 	DefaultInitrd       string

internal/paths/paths.go

@@ -4,7 +4,6 @@ import (
 	"errors"
 	"fmt"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -66,57 +65,64 @@ func Ensure(layout Layout) error {
 	return nil
 }
 
-func DetectRepoRoot() string {
+var executablePath = os.Executable
-	if env := os.Getenv("BANGER_REPO_ROOT"); env != "" {
+
-		return env
+func ResolveRuntimeDir(configuredRuntimeDir, deprecatedRepoRoot string) string {
-	}
+	for _, candidate := range []string{
-	candidates := []string{}
+		os.Getenv("BANGER_RUNTIME_DIR"),
-	if wd, err := os.Getwd(); err == nil {
+		os.Getenv("BANGER_REPO_ROOT"),
-		candidates = append(candidates, wd)
+		configuredRuntimeDir,
-	}
+		deprecatedRepoRoot,
-	if exe, err := os.Executable(); err == nil {
+	} {
-		candidates = append(candidates, filepath.Dir(exe))
+		if candidate = strings.TrimSpace(candidate); candidate != "" {
-	}
+			return filepath.Clean(candidate)
-	if look, err := exec.LookPath("firecracker"); err == nil {
-		candidates = append(candidates, filepath.Dir(look))
-	}
-	for _, candidate := range candidates {
-		if root := walkForRepoRoot(candidate); root != "" {
-			return root
 		}
 	}
+	exe, err := executablePath()
+	if err != nil {
+		return ""
+	}
+	exeDir := filepath.Dir(exe)
+	if filepath.Base(exeDir) == "bin" {
+		installRuntimeDir := filepath.Clean(filepath.Join(exeDir, "..", "lib", "banger"))
+		if HasRuntimeBundle(installRuntimeDir) {
+			return installRuntimeDir
+		}
+	}
+	if HasRuntimeBundle(exeDir) {
+		return exeDir
+	}
 	return ""
 }
 
-func walkForRepoRoot(start string) string {
+func HasRuntimeBundle(dir string) bool {
-	current := start
+	if strings.TrimSpace(dir) == "" {
-	for {
+		return false
-		if hasRepoArtifacts(current) {
+	}
-			return current
+	required := []string{
-		}
+		"firecracker",
-		parent := filepath.Dir(current)
+		"customize.sh",
-		if parent == current {
+		"packages.apt",
-			return ""
+		"wtf/root/boot/vmlinux-6.8.0-94-generic",
-		}
-		current = parent
 	}
-}
-
-func hasRepoArtifacts(dir string) bool {
-	required := []string{"firecracker", "README.md"}
 	for _, name := range required {
 		if _, err := os.Stat(filepath.Join(dir, name)); err != nil {
 			return false
 		}
 	}
-	return true
+	for _, name := range []string{"rootfs-docker.ext4", "rootfs.ext4"} {
+		if _, err := os.Stat(filepath.Join(dir, name)); err == nil {
+			return true
+		}
+	}
+	return false
 }
 
 func BangerdPath() (string, error) {
 	if env := os.Getenv("BANGER_DAEMON_BIN"); env != "" {
 		return env, nil
 	}
-	exe, err := os.Executable()
+	exe, err := executablePath()
 	if err != nil {
 		return "", err
 	}
@@ -129,16 +135,6 @@ func BangerdPath() (string, error) {
 			return candidate, nil
 		}
 	}
-	if root := DetectRepoRoot(); root != "" {
-		for _, candidate := range []string{
-			filepath.Join(root, "bangerd"),
-			filepath.Join(root, "bangerd.exe"),
-		} {
-			if _, err := os.Stat(candidate); err == nil {
-				return candidate, nil
-			}
-		}
-	}
 	return "", errors.New("bangerd binary not found next to banger; build ./cmd/bangerd")
 }
 

internal/paths/paths_test.go

@@ -0,0 +1,69 @@
+package paths
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestResolveRuntimeDirPrefersEnv(t *testing.T) {
+	t.Setenv("BANGER_RUNTIME_DIR", "/env/runtime")
+
+	if got := ResolveRuntimeDir("/config/runtime", "/deprecated/repo"); got != "/env/runtime" {
+		t.Fatalf("ResolveRuntimeDir() = %q, want /env/runtime", got)
+	}
+}
+
+func TestResolveRuntimeDirUsesInstalledLayout(t *testing.T) {
+	root := t.TempDir()
+	runtimeDir := filepath.Join(root, "lib", "banger")
+	createRuntimeBundle(t, runtimeDir)
+
+	origExecutablePath := executablePath
+	executablePath = func() (string, error) {
+		return filepath.Join(root, "bin", "banger"), nil
+	}
+	t.Cleanup(func() {
+		executablePath = origExecutablePath
+	})
+
+	if got := ResolveRuntimeDir("", ""); got != runtimeDir {
+		t.Fatalf("ResolveRuntimeDir() = %q, want %q", got, runtimeDir)
+	}
+}
+
+func TestResolveRuntimeDirUsesExecutableDirectoryBundle(t *testing.T) {
+	root := t.TempDir()
+	createRuntimeBundle(t, root)
+
+	origExecutablePath := executablePath
+	executablePath = func() (string, error) {
+		return filepath.Join(root, "banger"), nil
+	}
+	t.Cleanup(func() {
+		executablePath = origExecutablePath
+	})
+
+	if got := ResolveRuntimeDir("", ""); got != root {
+		t.Fatalf("ResolveRuntimeDir() = %q, want %q", got, root)
+	}
+}
+
+func createRuntimeBundle(t *testing.T, runtimeDir string) {
+	t.Helper()
+	for _, rel := range []string{
+		"firecracker",
+		"customize.sh",
+		"packages.apt",
+		"rootfs-docker.ext4",
+		"wtf/root/boot/vmlinux-6.8.0-94-generic",
+	} {
+		path := filepath.Join(runtimeDir, rel)
+		if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
+			t.Fatalf("mkdir %s: %v", filepath.Dir(path), err)
+		}
+		if err := os.WriteFile(path, []byte("test"), 0o644); err != nil {
+			t.Fatalf("write %s: %v", path, err)
+		}
+	}
+}