Add rootfs/kernel overrides

README.md

@@ -24,6 +24,8 @@ Minimal Firecracker launcher.
 - `--name`: must be unique and match `[a-z0-9][a-z0-9_-]{0,63}`.
 - `--vcpu`: defaults to 2, max 16.
 - `--ram`: MiB, defaults to 1024, max 32768.
+- `--rootfs`: path to the base rootfs image (default: `./rootfs.ext4`).
+- `--kernel`: path to the kernel image (default: `./vmlinux`).
 - `--home-size`: M/G suffixes supported (default: 2G).
 
 ## Storage Layout
@@ -59,8 +61,11 @@ reboot
 ## VM Info File
 Each VM writes a metadata file at `state/vms/<id>/info` with the following fields:
 - `id`: unique identifier for the VM instance.
+- `name`: VM name.
 - `pid`: Firecracker process ID.
 - `created_at`: timestamp when the VM was launched.
+- `rootfs`: root filesystem image path used to launch the VM.
+- `kernel`: kernel image path used to launch the VM.
 - `guest_ip`: IP address assigned to the guest.
 - `tap`: host TAP interface name attached to the bridge.
 - `api_sock`: path to the Firecracker API socket (stored under `$XDG_RUNTIME_DIR/banger/` when available).

customize.sh

@@ -36,6 +36,7 @@ mkdir -p "$VM_ROOT"
 
 BASE_ROOTFS="$DIR/rootfs.ext4"
 FC_BIN="$DIR/firecracker"
+
 KERNEL="$DIR/vmlinux"
 SSH_KEY="$DIR/id_ed25519"
 

run.sh

@@ -13,6 +13,8 @@ Options:
   --name <name>        VM name (lowercase letters, digits, -, _)
   --vcpu <count>       vCPU count (default: 2)
   --ram <mib>          RAM in MiB (default: 1024)
+  --rootfs <path>      Root filesystem image (default: ./rootfs.ext4)
+  --kernel <path>      Kernel image (default: ./vmlinux)
   --home-size <size>   Home disk size (e.g. 4G, 10240M)
   -h, --help           Show this help
 EOF
@@ -26,8 +28,8 @@ VM_ROOT="$STATE/vms"
 mkdir -p "$VM_ROOT"
 
 FC_BIN="$DIR/firecracker"
-KERNEL="$DIR/vmlinux"
-ROOTFS="$DIR/rootfs.ext4"
+DEFAULT_KERNEL="$DIR/vmlinux"
+DEFAULT_ROOTFS="$DIR/rootfs.ext4"
 SSH_KEY="$DIR/id_ed25519"
 NAMEGEN="$DIR/namegen"
 
@@ -48,6 +50,8 @@ DNS_SERVER="1.1.1.1"
 VCPU_COUNT="$DEFAULT_VCPU"
 RAM_MIB="$DEFAULT_RAM"
 HOME_SIZE="$DEFAULT_HOME_SIZE"
+KERNEL="$DEFAULT_KERNEL"
+ROOTFS="$DEFAULT_ROOTFS"
 VM_NAME=""
 
 shopt -s nullglob
@@ -93,6 +97,14 @@ while [[ $# -gt 0 ]]; do
       RAM_MIB="${2:-}"
       shift 2
       ;;
+    --rootfs)
+      ROOTFS="${2:-}"
+      shift 2
+      ;;
+    --kernel)
+      KERNEL="${2:-}"
+      shift 2
+      ;;
     --home-size)
       HOME_SIZE="${2:-}"
       shift 2
@@ -159,6 +171,14 @@ if ! [[ "$VM_NAME" =~ ^[a-z0-9][a-z0-9_-]{0,63}$ ]]; then
   log "invalid --name value: $VM_NAME"
   exit 1
 fi
+if [[ ! -f "$ROOTFS" ]]; then
+  log "rootfs not found: $ROOTFS"
+  exit 1
+fi
+if [[ ! -f "$KERNEL" ]]; then
+  log "kernel not found: $KERNEL"
+  exit 1
+fi
 if name_taken "$VM_NAME"; then
   log "name already in use: $VM_NAME"
   exit 1
@@ -365,6 +385,8 @@ id=$VM_ID
 name=$VM_NAME
 pid=$FC_PID
 created_at=$(date -Iseconds)
+rootfs=$ROOTFS
+kernel=$KERNEL
 guest_ip=$GUEST_IP
 tap=$TAP_DEV
 api_sock=$API_SOCK