Store VM metadata as JSON

README.md

@@ -4,7 +4,7 @@ Minimal Firecracker launcher.
 
 ## Requirements
 - Linux host with KVM (`/dev/kvm` access)
-- `sudo`, `ip`, `curl`, `ssh`
+- `sudo`, `ip`, `curl`, `ssh`, `jq`
 - `dmsetup`, `losetup`, `blockdev` (device-mapper snapshot for rootfs)
 - `e2cp`, `e2rm` (writes hostname and resolv.conf into rootfs snapshot)
 
@@ -63,22 +63,9 @@ 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).
-- `log`: path to the Firecracker log file.
-- `base_loop`: loop device backing the base rootfs (if present).
-- `cow_file`: copy-on-write image file (if present).
-- `cow_loop`: loop device for the COW image (if present).
-- `dm_name`: device-mapper name for the merged rootfs (if present).
-- `dm_dev`: device-mapper device path for the merged rootfs (if present).
+Each VM writes `state/vms/<id>/vm.json` with:
+- `meta`: local metadata (id, name, pid, created_at, guest_ip, tap, api_sock, log, rootfs, kernel, snapshot info).
+- `config`: full `/vm/config` response from Firecracker.
 
 ## Log Notes
 - `PCI: Fatal: No config space access function found` and `MissingAddressRange` lines are expected with `pci=off` in `run.sh`.