Add hardened Proxmox Debian cloud-init template script

Adds error handling (set -euo pipefail), VM ID/storage validation,
dependency checks, configurable storage/bridge/memory/cores via env
vars, image download caching, and auto-detection of the imported
disk instead of hardcoding filesystem-specific paths.

make-debian-cloudinit-template.sh

@@ -1,38 +1,95 @@
 #!/bin/bash
-# makes a cloud-init template vm from URL
-# call like ./make-debian-template.sh 9000
+# Build a Proxmox cloud-init template VM from a cloud image URL.
+#
+# Usage:
+#   ./make-debian-cloudinit-template.sh <VMID> [IMAGE_URL]
+#
+# Optional overrides (env vars):
+#   STORAGE   Proxmox storage pool for disks   (default: local-zfs)
+#   BRIDGE    Network bridge                   (default: vmbr0)
+#   MEMORY    RAM in MB                        (default: 2048)
+#   CORES     CPU cores                        (default: 4)
+#   NAME      Template name in Proxmox         (default: debian-cloudinit-<VMID>)
+#
+# Example:
+#   STORAGE=local-lvm BRIDGE=vmbr1 ./make-debian-cloudinit-template.sh 9000
+
+set -euo pipefail
+
+usage() {
+    grep '^#' "$0" | sed -e 's/^#//' -e 's/^ //' | head -n 12
+}
+
+if [[ "${1:-}" == "-h" || "${1:-}" == "--help" ]]; then
+    usage
+    exit 0
+fi
 
-# Check for root priviliges
 if [[ $EUID -ne 0 ]]; then
-   printf "Please run as root:\nsudo %s\n" "${0}"
-   exit 1
+    printf "Please run as root:\nsudo %s\n" "$0"
+    exit 1
 fi
 
+for bin in wget qm pvesm; do
+    if ! command -v "$bin" >/dev/null; then
+        echo "Required command '$bin' not found. Is this running on a Proxmox host?" >&2
+        exit 1
+    fi
+done
+
+ID=${1:-}
+if [[ -z "$ID" || ! "$ID" =~ ^[0-9]+$ ]]; then
+    echo "Error: a numeric VM ID is required." >&2
+    usage
+    exit 1
+fi
+
+if qm status "$ID" &>/dev/null; then
+    echo "Error: VM ID $ID already exists." >&2
+    exit 1
+fi
 
-ID=$1
 URL=${2:-"https://cloud.debian.org/images/cloud/trixie/latest/debian-13-genericcloud-amd64.qcow2"}
-FS=btrfs
-# decide between lvm, zfs or btrfs
+STORAGE=${STORAGE:-local-zfs}
+BRIDGE=${BRIDGE:-vmbr0}
+MEMORY=${MEMORY:-2048}
+CORES=${CORES:-4}
+NAME=${NAME:-"debian-cloudinit-$ID"}
 
-wget $URL -O cloud-init.qcow2
-qm create $ID --net0 virtio,bridge=vmbr0 --scsihw virtio-scsi-pci --memory 2048 --cores 4 --machine q35
-command -v virt-customize
-# install libguestfs-tools to have virt-customize
-
-if [[ $? -eq 0 ]]; then
-   echo "installing qemu-guest-agent into guest"
-   virt-customize -a cloud-init.qcow2 --install qemu-guest-agent
-   qm set $ID --agent 1
-else
-   echo "will not install qemu-guest-agent into guest"
+if ! pvesm status -storage "$STORAGE" &>/dev/null; then
+    echo "Error: storage pool '$STORAGE' not found (check STORAGE env var)." >&2
+    exit 1
 fi
 
-qm importdisk $ID  ./cloud-init.qcow2 local-$FS
-[ "$FS" == "btrfs" ] && qm set $ID --scsi0 local-$FS:$ID/vm-$ID-disk-0.raw
-[ "$FS" == "lvm" ] && qm set $ID --scsi0 local-$FS:vm-$ID-disk-0
-[ "$FS" == "zfs" ] && qm set $ID --scsi0 local-$FS:vm-$ID-disk-0
-qm set $ID --scsi1 local-$FS:cloudinit
-qm set $ID --serial0 socket --vga serial0
-qm set $ID --name cloud-init-template
-qm set $ID --boot order=scsi0
-qm template $ID
+trap 'echo "Failed while building VM $ID. It may be left in a partial state — check with: qm config $ID  (clean up with: qm destroy $ID)" >&2' ERR
+
+CACHE_DIR=/var/tmp/pve-cloudinit-images
+mkdir -p "$CACHE_DIR"
+IMAGE_FILE="$CACHE_DIR/$(basename "$URL")"
+
+echo "Fetching cloud image (cached under $CACHE_DIR, re-used if unchanged)..."
+wget -N -P "$CACHE_DIR" "$URL"
+
+qm create "$ID" --net0 "virtio,bridge=$BRIDGE" --scsihw virtio-scsi-pci --memory "$MEMORY" --cores "$CORES" --machine q35
+
+if command -v virt-customize >/dev/null; then
+    echo "Installing qemu-guest-agent into guest image..."
+    virt-customize -a "$IMAGE_FILE" --install qemu-guest-agent
+    qm set "$ID" --agent 1
+else
+    echo "virt-customize not found (install libguestfs-tools for this); skipping in-guest qemu-guest-agent install."
+fi
+
+qm importdisk "$ID" "$IMAGE_FILE" "$STORAGE"
+DISK=$(qm config "$ID" | awk -F': ' '/^unused0:/ {print $2}')
+if [[ -z "$DISK" ]]; then
+    echo "Error: could not find imported disk on VM $ID." >&2
+    exit 1
+fi
+
+qm set "$ID" --scsi0 "$DISK"
+qm set "$ID" --scsi1 "$STORAGE:cloudinit"
+qm set "$ID" --name "$NAME" --boot order=scsi0 --serial0 socket --vga serial0
+qm template "$ID"
+
+echo "Template $ID ($NAME) created from $URL using storage '$STORAGE'."