core: validate container ID before pct create to prevent failures (#10729)

* feat: validate container ID before pct create to prevent failures

Add validation to ensure container IDs are not already in use before attempting to create containers. This prevents pct create failures when an ID is already assigned to a VM/LXC or used in LVM volumes.

Changes:
- Add validate_container_id() and get_valid_container_id() functions to build.func
- Validate ID in base_settings() for default installation method
- Validate ID in advanced_settings() dialog with user prompt for next available ID
- Add validation to turnkey.sh with interactive dialog
- Add validation to all-templates.sh with automatic ID correction

Checks performed:
- Container config file existence (/etc/pve/lxc/*.conf)
- VM config file existence (/etc/pve/qemu-server/*.conf)
- LVM logical volume usage

Fixes issue where container creation would fail if the suggested/chosen ID was already in use.

* feat: validate container ID before pct create to prevent failures

Add validation to ensure container IDs are not already in use before attempting to create containers. This prevents pct create failures when an ID is already assigned to a VM/LXC or used in LVM volumes.

Changes:
- Add validate_container_id() and get_valid_container_id() functions to build.func
- Validate ID in base_settings() for default installation method
- Validate ID in advanced_settings() dialog with user prompt for next available ID
- Add validation to turnkey.sh with interactive dialog
- Add validation to all-templates.sh with automatic ID correction

Checks performed:
- Container config file existence (/etc/pve/lxc/*.conf)
- VM config file existence (/etc/pve/qemu-server/*.conf)
- LVM logical volume usage

Fixes issue where container creation would fail if the suggested/chosen ID was already in use.

* Update turnkey.sh

* Update build.func

turnkey/turnkey.sh

@@ -42,6 +42,29 @@ function msg() {
   local TEXT="$1"
   echo -e "$TEXT"
 }
+function validate_container_id() {
+  local ctid="$1"
+  # Check if ID is numeric
+  if ! [[ "$ctid" =~ ^[0-9]+$ ]]; then
+    return 1
+  fi
+  # Check if config file exists for VM or LXC
+  if [[ -f "/etc/pve/qemu-server/${ctid}.conf" ]] || [[ -f "/etc/pve/lxc/${ctid}.conf" ]]; then
+    return 1
+  fi
+  # Check if ID is used in LVM logical volumes
+  if lvs --noheadings -o lv_name 2>/dev/null | grep -qE "(^|[-_])${ctid}($|[-_])"; then
+    return 1
+  fi
+  return 0
+}
+function get_valid_container_id() {
+  local suggested_id="${1:-$(pvesh get /cluster/nextid)}"
+  while ! validate_container_id "$suggested_id"; do
+    suggested_id=$((suggested_id + 1))
+  done
+  echo "$suggested_id"
+}
 function cleanup_ctid() {
   if pct status $CTID &>/dev/null; then
     if [ "$(pct status $CTID | awk '{print $2}')" == "running" ]; then
@@ -99,9 +122,26 @@ turnkey=$(whiptail --backtitle "Proxmox VE Helper Scripts" --title "TurnKey LXCs
 # Setup script environment
 PASS="$(openssl rand -base64 8)"
 # Prompt user to confirm container ID
-  CTID=$(whiptail --backtitle "Container ID" --title "Choose the Container ID" --inputbox "Enter the conatiner ID..." 8 40 $(pvesh get /cluster/nextid) 3>&1 1>&2 2>&3)
+while true; do
+  CTID=$(whiptail --backtitle "Container ID" --title "Choose the Container ID" --inputbox "Enter the container ID..." 8 40 $(pvesh get /cluster/nextid) 3>&1 1>&2 2>&3)
+
+  # Check if user cancelled
+  [ -z "$CTID" ] && die "No Container ID selected"
+
+  # Validate Container ID
+  if ! validate_container_id "$CTID"; then
+    SUGGESTED_ID=$(get_valid_container_id "$CTID")
+    if whiptail --backtitle "Container ID" --title "ID Already In Use" --yesno "Container/VM ID $CTID is already in use.\n\nWould you like to use the next available ID ($SUGGESTED_ID)?" 10 58; then
+      CTID="$SUGGESTED_ID"
+      break
+    fi
+    # User declined, loop back to input
+  else
+    break
+  fi
+done
 # Prompt user to confirm Hostname
-  HOST_NAME=$(whiptail --backtitle "Hostname" --title "Choose the Hostname" --inputbox "Enter the containers Hostname..." 8 40 "turnkey-${turnkey}" 3>&1 1>&2 2>&3)
+HOST_NAME=$(whiptail --backtitle "Hostname" --title "Choose the Hostname" --inputbox "Enter the containers Hostname..." 8 40 "turnkey-${turnkey}" 3>&1 1>&2 2>&3)
 PCT_OPTIONS="
     -features keyctl=1,nesting=1
     -hostname $HOST_NAME
@@ -206,8 +246,8 @@ echo "TurnKey ${turnkey} password: ${PASS}" >>~/turnkey-${turnkey}.creds # file
 TUN_DEVICE_REQUIRED=("openvpn") # Setup this way in case future turnkeys also need tun access
 if printf '%s\n' "${TUN_DEVICE_REQUIRED[@]}" | grep -qw "${turnkey}"; then
   info "${turnkey} requires access to /dev/net/tun on the host. Modifying the container configuration to allow this."
-  echo "lxc.cgroup2.devices.allow: c 10:200 rwm" >> /etc/pve/lxc/${CTID}.conf
-  echo "lxc.mount.entry: /dev/net/tun dev/net/tun none bind,create=file 0 0" >> /etc/pve/lxc/${CTID}.conf
+  echo "lxc.cgroup2.devices.allow: c 10:200 rwm" >>/etc/pve/lxc/${CTID}.conf
+  echo "lxc.mount.entry: /dev/net/tun dev/net/tun none bind,create=file 0 0" >>/etc/pve/lxc/${CTID}.conf
   sleep 5
 fi