Improve VM lifecycle tooling

Make spawned VMs easier to use and restore from the host.

Add shared DNS and runtime helpers, publish <vm-name>.vm records through mapdns, and teach run/customize/interactive/restore to persist the metadata needed for SSH, DNS cleanup, and clean restores.

Seed per-VM /home and /var disks from the rootfs snapshot so package state is present on first boot, add an interactive customization entrypoint plus ssh.sh and human-friendly list output, and let stop/kill/rm operate on multiple VM identifiers.

Tear down stale TAP, dm, and loop state when VMs stop so restore can recreate them safely, and validate the updated scripts with bash -n plus targeted dry-run harnesses for teardown and restore paths.

run.sh

@@ -25,6 +25,7 @@ EOF
 log "starting"
 
 DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+source "$DIR/dns.sh"
 STATE="$DIR/state"
 VM_ROOT="$STATE/vms"
 mkdir -p "$VM_ROOT"
@@ -254,6 +255,41 @@ BASE_LOOP=""
 COW_LOOP=""
 DM_NAME="fc-rootfs-$VM_TAG"
 DM_DEV=""
+SEED_ROOT_MNT="$VM_DIR/mnt-root"
+SEED_HOME_MNT="$VM_DIR/mnt-home"
+SEED_VAR_MNT="$VM_DIR/mnt-var"
+DNS_NAME=""
+
+unmount_if_needed() {
+  local mount_path="$1"
+  [[ -n "$mount_path" ]] || return 0
+  sudo umount "$mount_path" 2>/dev/null || true
+}
+
+seed_volume_from_rootfs() {
+  local source_dir="$1"
+  local target_image="$2"
+  local target_mount="$3"
+  local label="$4"
+
+  if [[ ! -d "$source_dir" ]]; then
+    log "source directory missing in rootfs snapshot: $label"
+    exit 1
+  fi
+
+  mkdir -p "$target_mount"
+  sudo mount "$target_image" "$target_mount"
+  sudo cp -a "$source_dir/." "$target_mount/"
+  sudo umount "$target_mount"
+}
+
+populate_data_disks() {
+  mkdir -p "$SEED_ROOT_MNT" "$SEED_HOME_MNT" "$SEED_VAR_MNT"
+  sudo mount -o ro "$DM_DEV" "$SEED_ROOT_MNT"
+  seed_volume_from_rootfs "$SEED_ROOT_MNT/home" "$HOME_PATH" "$SEED_HOME_MNT" "/home"
+  seed_volume_from_rootfs "$SEED_ROOT_MNT/var" "$VAR_PATH" "$SEED_VAR_MNT" "/var"
+  sudo umount "$SEED_ROOT_MNT"
+}
 
 cleanup() {
   local exit_code=$?
@@ -268,6 +304,10 @@ cleanup() {
     sudo ip link del "$TAP_DEV" 2>/dev/null || true
   fi
   rm -f "${API_SOCK:-}"
+  unmount_if_needed "${SEED_VAR_MNT:-}"
+  unmount_if_needed "${SEED_HOME_MNT:-}"
+  unmount_if_needed "${SEED_ROOT_MNT:-}"
+  banger_dns_remove_record_name "${DNS_NAME:-}"
   if [[ -n "${DM_NAME:-}" ]]; then
     sudo dmsetup remove "$DM_NAME" 2>/dev/null || true
   fi
@@ -328,6 +368,10 @@ if ! command -v e2cp >/dev/null 2>&1 || ! command -v e2rm >/dev/null 2>&1; then
   log "e2cp and e2rm are required to set hostname and resolv.conf"
   exit 1
 fi
+if ! command -v mount >/dev/null 2>&1 || ! command -v umount >/dev/null 2>&1; then
+  log "mount and umount are required to populate home/var disks"
+  exit 1
+fi
 if ! command -v jq >/dev/null 2>&1; then
   log "jq is required to persist VM metadata"
   exit 1
@@ -368,6 +412,9 @@ sudo e2cp "$HOSTS_TMP" "$DM_DEV:/etc/hosts" >/dev/null 2>&1 || {
   exit 1
 }
 
+log "populating /home and /var disks from rootfs snapshot"
+populate_data_disks
+
 # Host bridge
 if ! ip link show "$BR_DEV" >/dev/null 2>&1; then
   log "creating host bridge $BR_DEV ($BR_IP/$CIDR)"
@@ -494,9 +541,10 @@ log "starting virtual machine"
 "${CURL_CMD[@]}" --unix-socket "$API_SOCK" -X PUT http://localhost/actions \
   -H "Content-Type: application/json" \
   -d '{ "action_type": "InstanceStart" }' >/dev/null
-VM_STARTED=1
 VM_CONFIG_JSON="$("${CURL_CMD[@]}" --unix-socket "$API_SOCK" -sS http://localhost/vm/config)"
 CREATED_AT="$(date -Iseconds)"
+DNS_NAME="$(banger_dns_name "$VM_NAME")"
+banger_dns_write_record "$VM_NAME" "$GUEST_IP"
 jq -n \
   --arg id "$VM_ID" \
   --arg name "$VM_NAME" \
@@ -515,9 +563,11 @@ jq -n \
   --arg cow_loop "$COW_LOOP" \
   --arg dm_name "$DM_NAME" \
   --arg dm_dev "$DM_DEV" \
+  --arg dns_name "$DNS_NAME" \
   --argjson config "$VM_CONFIG_JSON" \
-  '{meta:{id:$id,name:$name,pid:$pid,created_at:$created_at,guest_ip:$guest_ip,tap:$tap,api_sock:$api_sock,log:$log,rootfs:$rootfs,kernel:$kernel,home_path:$home_path,var_path:$var_path,base_loop:$base_loop,cow_file:$cow_file,cow_loop:$cow_loop,dm_name:$dm_name,dm_dev:$dm_dev},config:$config}' \
+  '{meta:{id:$id,name:$name,pid:$pid,created_at:$created_at,guest_ip:$guest_ip,tap:$tap,api_sock:$api_sock,log:$log,rootfs:$rootfs,kernel:$kernel,home_path:$home_path,var_path:$var_path,base_loop:$base_loop,cow_file:$cow_file,cow_loop:$cow_loop,dm_name:$dm_name,dm_dev:$dm_dev,dns_name:$dns_name},config:$config}' \
   > "$VM_DIR/vm.json"
+VM_STARTED=1
 
 log "vm started successfully"
 log "guest ip: $GUEST_IP"