Add sync-host-keys.sh and create-proxmox-resource.sh

sync-host-keys.sh: generates/registers SSH host keys and their
.sops.yaml/secrets/*.yaml recipients for flake targets, idempotently.
--all, <target>, --remove, --regenerate-all-keys, all with --dry-run
(verified zero-side-effect via a sandboxed git-status check across every
mode). Only ever touches anchors with a corresponding host-keys/ file --
&admin and any hand-registered real-host anchor are never listed,
removed, or regenerated. Supersedes running prepare-host-key.sh one host
at a time for any target that already has a flake entry.

create-proxmox-resource.sh: builds a lxc-*/proxmox-* target's
tarball/disk image and creates it on a real Proxmox node, or reconfigures
an existing resource's cores/memory/disk (--modify, always requires
typing the VMID back to confirm). Refuses to create a new resource for a
VMID that already exists, and refuses to duplicate a host identity that
already has a real deployment elsewhere (variables.nix's new
deployedTargets, checked by hostName so it also catches cross-platform
duplicates) unless --allow-duplicate-host is passed. --dry-run throughout.

scripts/env.sh centralizes the Proxmox connection config both scripts
(and future ones) share. Also fixes an unrelated gap found along the way:
proxmox-* Disko image builds write their .raw file straight into the
repo root, and .gitignore never covered it.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01La55Nsss8jZ7ZuzUV9mfot

.gitignore

@@ -3,9 +3,19 @@
 result
 result-*
 
+# Disko's proxmox-* image-builder writes the finished .raw disk image
+# directly into the current directory, not into a result-* symlink (see
+# docs/proxmox-images.md, scripts/create-proxmox-resource.sh) — several GB
+# each, never meant to be committed.
+*.raw
+
 # Ignore automatically generated direnv output
 .direnv
 
+# Python bytecode cache (scripts/lib/*.py)
+__pycache__/
+*.pyc
+
 # Locally-generated SSH host keys staged for transfer to a new machine
 # during install (see scripts/prepare-host-key.sh) — never commit these.
 host-keys/

CLAUDE.md

@@ -62,7 +62,7 @@ There is no test suite — "correctness" here means the flake evaluates and
 sweeps: after editing one or two hosts/modules, evaluate just the
 `nixosConfigurations.<host>` you touched (plus any `config.system.build.tarball`
 /`diskoImagesScript`/package output affected) rather than looping over every
-host — `codex-maintenance.sh` evaluates 19 hosts plus every package/tarball/
+host — `codex-maintenance.sh` evaluates 18 hosts plus every package/tarball/
 image variant now and is slow to run after each small change. Reserve a full
 `codex-maintenance.sh` run for changes that plausibly affect every host
 (`modules/common/*`, `flake.nix`, `variables.nix`) or as a final check before
@@ -70,6 +70,44 @@ committing. This is a session-workflow preference only — it does not apply to
 CI, which should keep running the full script on every push/PR regardless of
 diff size; that's the point of it.
 
+## Scripts
+
+Beyond `codex-setup.sh`/`codex-maintenance.sh` above, `scripts/` also has:
+
+- `scripts/sync-host-keys.sh` — generates/registers SSH host keys and their
+  `.sops.yaml`/`secrets/*.yaml` recipients for flake targets, idempotently
+  (`--all`, `<target>`, `--remove`, `--regenerate-all-keys`, all with
+  `--dry-run`). The primary tool for provisioning a new host's secrets
+  access — see "Creating a new machine" in `docs/auto-installer.md`.
+- `scripts/prepare-host-key.sh` — narrower predecessor: generates a key by
+  an arbitrary name without touching `.sops.yaml`. Still useful to
+  pre-generate a key before its flake target exists yet, since
+  `sync-host-keys.sh` can only act on targets `nixosConfigurations` already
+  has.
+- `scripts/create-proxmox-resource.sh` — builds a `lxc-*`/`proxmox-*`
+  target's tarball/disk image and creates it on a real Proxmox node
+  (`pct restore` / `qm create`+`importdisk`), or reconfigures an existing
+  resource's cores/memory/disk size (`--modify`, always requires typing the
+  VMID back to confirm). Refuses to create a target whose host identity
+  already has a real deployment elsewhere (`variables.nix`'s
+  `deployedTargets`) unless `--allow-duplicate-host` is passed.
+  `--dry-run` throughout both modes.
+- `scripts/env.sh` — shared config (`PROXMOX_HOST`, storage pool, bridge,
+  default cores/memory) sourced by `create-proxmox-resource.sh`. Add new
+  cross-script config here instead of duplicating it per-script.
+- `scripts/bump-nixpkgs-release.sh` — bumps `flake.nix`'s `nixpkgs.url`/
+  `home-manager.url` in place. Exists because flake input URLs can't
+  reference `variables.nix` (confirmed empirically — `nix flake metadata`
+  errors on it), so this is the closest equivalent to a single source of
+  truth for the tracked release.
+
+`sync-host-keys.sh` and `create-proxmox-resource.sh` genuinely mutate real
+state when run for real (not `--dry-run`): real `secrets/*.yaml`
+recipients, real Proxmox VMs/containers. They require the operator's own
+SSH/sops access, which an agent session doesn't have — but don't suggest
+running either non-dry-run without the operator's explicit go-ahead even
+if it becomes technically reachable.
+
 ## Architecture
 
 `flake.nix` is the single entry point. It generates one
@@ -129,6 +167,12 @@ removing a host.
   `lxc-*`). Also carries `imageSize`/`imageName`, letting every `proxmox-*`
   host be built as a standalone, `qm importdisk`-ready `.raw` image with no
   install step — see `docs/proxmox-images.md`.
+- `modules/disko/linode.nix` — `linode-*`'s disko config, deliberately
+  different in kind from the Proxmox one: Linode provisions and sizes
+  `/dev/sda`/`/dev/sdb` itself as whole, unpartitioned devices before the OS
+  boots, so this declares them with `destroy = false` (disko never wipes
+  them) and a bare `filesystem`/`swap` content type instead of a partition
+  table — idempotent against an already-provisioned disk, never destructive.
 - `modules/boot/efi.nix` — systemd-boot + EFI vars, paired with the disko module.
 - `modules/installer/` — the auto-installer environment (ISO, also served as
   PXE netboot): `common.nix` (shared config + the generated

README.md

@@ -27,6 +27,11 @@ list:
 | `linode-gui` / `proxmox-gui` / `lxc-gui` | Cinnamon desktop workstation (`proxmox-gui` is the real, deployed one — previously the flat `nixos` target) |
 | `proxmox-pxe-boot` / `lxc-pxe-boot` | HTTP/iPXE boot asset host (`proxmox-pxe-boot` is the real, deployed one — previously the flat `pxe-boot` target) |
 
+The "(real, deployed)" targets above are also tracked machine-readably in
+`variables.nix`'s `deployedTargets` — keep both in sync when a deployment
+changes. `scripts/create-proxmox-resource.sh` reads that list to refuse
+creating a same-identity duplicate of an already-deployed host by accident.
+
 Each buildtype's `hosts/<name>/host.nix` carries the per-machine identity
 (hostname, hostId, per-machine secrets, `system.stateVersion`) that must stay
 fixed regardless of which platform it's built for — see
@@ -56,7 +61,7 @@ nix eval --json .#nixosConfigurations --apply builtins.attrNames | jq -r '.[]'
 | `modules/installer/` | Auto-installer environment (ISO, also served as PXE netboot) — see `docs/auto-installer.md` |
 | `host-keys/` | Gitignored, locally-generated SSH host keys for the auto-installer — see `docs/auto-installer.md` |
 | `docs/` | Operational notes for cache, builders, lock updates, boot services, the auto-installer, and Proxmox image builds |
-| `scripts/` | Codex setup, validation, and host-key-prep helpers |
+| `scripts/` | Codex setup, validation, host-key, release-bump, and Proxmox resource helpers |
 
 ## Validation
 
@@ -104,6 +109,11 @@ Three different paths depending on target, none of them involving a manual
   disk image and attached to a new VM with no install step — see
   `docs/proxmox-images.md`.
 
+`scripts/create-proxmox-resource.sh --type lxc|vm --host <name>` automates
+either of the last two end to end (build, host-key registration, upload,
+`pct restore`/`qm create`), with `--dry-run` and a guard against duplicating
+an already-deployed host's identity. See its `--help`.
+
 ## Security Notes
 
 Do not commit tokens, private keys, live credentials, or new password hashes

docs/auto-installer.md

@@ -56,8 +56,14 @@ it does for the ISO/PXE installer images.
   `docs/pxe-boot.md`).
 - `modules/installer/host-keys.nix` — optionally bakes pre-generated SSH
   host keys into the image; see "Host keys" below.
-- `scripts/prepare-host-key.sh` — admin-workstation pre-flight tool, see
-  "Creating a New Machine" below.
+- `scripts/sync-host-keys.sh` — admin-workstation tool that generates,
+  registers, and (via `--remove`/`--regenerate-all-keys`) retires host
+  keys; see "Creating a New Machine" below.
+- `scripts/prepare-host-key.sh` — narrower predecessor: generates a single
+  key by an arbitrary name without touching `.sops.yaml`. Still useful for
+  pre-generating a key *before* its flake target exists (`sync-host-keys.sh`
+  can only act on targets `nixosConfigurations` already has); otherwise
+  `sync-host-keys.sh` does the same thing and more.
 
 Flake outputs:
 
@@ -164,24 +170,28 @@ host consumes any sops-nix secret — as of this writing, that's every host
 (`modules/common/configuration.nix` puts the root/nixos password hash and the
 GitHub token behind sops-nix for all of them).
 
-1. **On your admin workstation**, decide the new machine's flake target name
-   (`<platform>-<buildtype>`, e.g. `proxmox-server`) and generate + register
-   its host key:
+1. **Add the flake target** — `hosts/<name>/host.nix` plus the matching
+   `mkTarget { ... }` entry in `flake.nix`'s `generatedTargets` (see
+   "Composition pattern" in `CLAUDE.md`). No secrets involved yet, so this
+   is safe to commit on its own if you want a clean history.
+
+2. **On your admin workstation, generate and register its host key:**
 
    ```sh
-   ./scripts/prepare-host-key.sh <hostname>
+   ./scripts/sync-host-keys.sh <flake-target>
    ```
 
-   This generates `host-keys/<hostname>_ssh_host_ed25519_key(.pub)` and
-   prints the `.sops.yaml` snippet to add, which secrets files to
-   re-encrypt it into, and the next steps below.
+   This generates `host-keys/<flake-target>_ssh_host_ed25519_key(.pub)`,
+   adds it as a new `.sops.yaml` anchor, works out which `secrets/*.yaml`
+   files this specific host actually references (from its own
+   `config.sops.secrets`, not guessed), adds it to each one's
+   `key_groups`, and re-encrypts them with `sops updatekeys` — no manual
+   YAML editing. Safe to re-run; it only fills in what's missing.
 
-2. **Edit `.sops.yaml`** with the printed snippet, then re-encrypt every
-   secrets file you added the new host to:
-
-   ```sh
-   nix-shell -p sops --run 'sops updatekeys secrets/common.yaml'
-   ```
+   Doing this for every host that needs one at once — after adding several
+   new targets, or just to catch up any that were missed — is
+   `./scripts/sync-host-keys.sh --all`. See `scripts/sync-host-keys.sh --help`
+   for its other modes (`--remove`, `--regenerate-all-keys`).
 
 3. **Commit and push.** The flake build the installer uses has to see the
    new recipient before you install, or decryption fails on first boot

docs/proxmox-images.md

@@ -7,6 +7,12 @@ config (`modules/disko/proxmox.nix`) already used to format a real disk on
 install, so there's nothing host-specific to write; it's available for every
 `proxmox-*` target automatically.
 
+`scripts/create-proxmox-resource.sh --type vm --host <name>` automates the
+whole walkthrough below (and the equivalent LXC one) end to end, including
+host-key handling and upload — see its `--help`. The steps here are what it
+runs under the hood, useful for doing any of it by hand or understanding
+what it does before you trust it against real infrastructure.
+
 ## Building
 
 ```sh
@@ -43,9 +49,10 @@ sudo ./result \
   --build-memory 2048
 ```
 
-Generate the key first with `scripts/prepare-host-key.sh <hostname>`, same
-as any other host — see `docs/auto-installer.md` for the full sops.yaml
-registration walkthrough.
+Generate the key first with `scripts/sync-host-keys.sh <hostname>`, same
+as any other host — see `docs/auto-installer.md` for the full walkthrough
+(it registers the new key in `.sops.yaml` and re-encrypts the affected
+`secrets/*.yaml` files too, no manual editing needed).
 
 ## Deploying to Proxmox
 

scripts/create-proxmox-resource.sh

@@ -0,0 +1,432 @@
+#!/usr/bin/env bash
+# Creates new Proxmox VMs/LXC containers from this flake, and reconfigures
+# existing ones -- the manual workflows in docs/proxmox-images.md (VM) and
+# docs/auto-installer.md's "LXC hosts" section (container), automated.
+#
+# Usage:
+#   scripts/create-proxmox-resource.sh --type lxc|vm --host <name> [options]
+#   scripts/create-proxmox-resource.sh --type lxc|vm --list
+#   scripts/create-proxmox-resource.sh --modify --vmid <n> [--cores N] [--memory MB] [--grow-disk GB]
+#
+# SAFETY:
+#   - The default (create) mode only ever creates a NEW resource -- it
+#     refuses to run if the target VMID already exists on the node.
+#   - --modify only ever touches a resource you name explicitly via
+#     --vmid, shows exactly what will change first, and (outside
+#     --dry-run) always requires typing that VMID back to confirm before
+#     anything is sent to the node. There is no bulk/implicit modify.
+#   - Neither mode can start/stop/delete a resource. Not implemented on
+#     purpose -- ask before adding it.
+#
+# See --help for the full option list.
+set -euo pipefail
+
+repo_root="$(cd "$(dirname "$0")/.." && pwd)"
+# shellcheck source=env.sh
+source "${repo_root}/scripts/env.sh"
+
+sync_keys="${repo_root}/scripts/sync-host-keys.sh"
+
+usage() {
+  cat <<EOF
+Usage: $0 --type lxc|vm --host <name> [options]      (create)
+       $0 --type lxc|vm --list                        (list --host values)
+       $0 --modify --vmid <n> [options]                (reconfigure)
+
+Create mode (default):
+  --type lxc|vm        lxc = container, built as a pct-restorable tarball.
+                        vm  = VM, built as a Disko .raw disk image (UEFI/OVMF).
+  --host <name>         Which host identity to deploy -- matches
+                        config.networking.hostName (server, docker,
+                        nix-cache, nixos, pxe-boot, nix-minimal). Use
+                        --list to see what's available for --type.
+  --name <name>          Proxmox display name/hostname (default: the flake
+                          target name, e.g. lxc-server)
+  --vmid <n>              Numeric VMID (default: next free, via
+                          \`pvesh get /cluster/nextid\` on the node).
+                          Refuses to run if this ID already exists.
+  --disk-size <GB>           lxc only, at create time: overrides the
+                              restored rootfs's absolute size.
+  --image <path>              Use this local image/tarball instead of
+                              building one from the flake.
+  --allow-duplicate-host        Required if --host already has a real
+                                deployment elsewhere (variables.nix's
+                                deployedTargets) -- otherwise refused, since
+                                it'd share that host's hostName/hostId.
+
+Modify mode (reconfigure an EXISTING resource -- requires --modify):
+  --modify                Switch to modify mode.
+  --vmid <n>                Required: which existing resource to change.
+                            Type/VM-vs-CT is auto-detected on the node.
+  --grow-disk <GB>            Grow the primary disk by this many GB
+                              (qm/pct resize; Proxmox only supports
+                              growing, never shrinking, an existing disk).
+  At least one of --cores / --memory / --grow-disk is required. Always
+  prints the current -> new values and requires typing the VMID back to
+  confirm, even outside --dry-run.
+
+Shared:
+  --cores <n>              create: default \$PROXMOX_DEFAULT_CORES (${PROXMOX_DEFAULT_CORES}).
+                            modify: omit to leave unchanged.
+  --memory <MB>              create: default \$PROXMOX_DEFAULT_MEMORY_MB (${PROXMOX_DEFAULT_MEMORY_MB}).
+                              modify: omit to leave unchanged.
+  --storage <pool>              (default: \$PROXMOX_STORAGE, ${PROXMOX_STORAGE})
+  --iso-storage <pool>            (default: \$PROXMOX_ISO_STORAGE, ${PROXMOX_ISO_STORAGE})
+  --bridge <bridge>                (default: \$PROXMOX_BRIDGE, ${PROXMOX_BRIDGE})
+  --node <host>                     Proxmox node to SSH into (default:
+                                    \$PROXMOX_HOST, ${PROXMOX_HOST})
+  --dry-run                           Print the full plan; touch nothing
+                                      local or remote, no prompts.
+  -h, --help
+
+Config for --storage/--bridge/--node/etc. lives in scripts/env.sh -- edit
+that instead of passing the same flag every time.
+EOF
+}
+
+dry_run=0
+modify=0
+type=""
+host=""
+name=""
+vmid=""
+cores=""
+memory=""
+disk_size=""
+grow_disk=""
+image=""
+storage="$PROXMOX_STORAGE"
+iso_storage="$PROXMOX_ISO_STORAGE"
+bridge="$PROXMOX_BRIDGE"
+node="$PROXMOX_HOST"
+do_list=0
+allow_duplicate_host=0
+
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+  --type) type="$2"; shift 2 ;;
+  --host) host="$2"; shift 2 ;;
+  --name) name="$2"; shift 2 ;;
+  --vmid) vmid="$2"; shift 2 ;;
+  --cores) cores="$2"; shift 2 ;;
+  --memory) memory="$2"; shift 2 ;;
+  --disk-size) disk_size="$2"; shift 2 ;;
+  --grow-disk) grow_disk="$2"; shift 2 ;;
+  --image) image="$2"; shift 2 ;;
+  --storage) storage="$2"; shift 2 ;;
+  --iso-storage) iso_storage="$2"; shift 2 ;;
+  --bridge) bridge="$2"; shift 2 ;;
+  --node) node="$2"; shift 2 ;;
+  --list) do_list=1; shift ;;
+  --allow-duplicate-host) allow_duplicate_host=1; shift ;;
+  --modify) modify=1; shift ;;
+  --dry-run) dry_run=1; shift ;;
+  -h | --help) usage; exit 0 ;;
+  *) echo "Unknown option: $1" >&2; usage >&2; exit 1 ;;
+  esac
+done
+
+ssh_target="${PROXMOX_SSH_USER}@${node}"
+
+remote() {
+  if [[ "$dry_run" -eq 1 ]]; then
+    echo "[dry-run] ssh ${ssh_target} -- $*"
+  else
+    ssh "$ssh_target" "$@"
+  fi
+}
+
+# ============================================================ modify mode
+cmd_modify() {
+  if [[ -z "$vmid" ]]; then
+    echo "ERROR: --modify requires --vmid." >&2
+    exit 1
+  fi
+  if [[ -z "$cores" && -z "$memory" && -z "$grow_disk" ]]; then
+    echo "ERROR: --modify needs at least one of --cores / --memory / --grow-disk." >&2
+    exit 1
+  fi
+
+  echo "Looking up VMID ${vmid} on ${node}..."
+  local kind current_cores current_memory disk_key
+  if ssh "$ssh_target" "qm status ${vmid}" >/dev/null 2>&1; then
+    kind="vm"
+    disk_key="scsi0"
+  elif ssh "$ssh_target" "pct status ${vmid}" >/dev/null 2>&1; then
+    kind="lxc"
+    disk_key="rootfs"
+  else
+    echo "ERROR: VMID ${vmid} doesn't exist on ${node} -- nothing to modify." >&2
+    exit 1
+  fi
+
+  local config_cmd="qm config ${vmid}"
+  [[ "$kind" == "lxc" ]] && config_cmd="pct config ${vmid}"
+  local current_config
+  current_config="$(ssh "$ssh_target" "$config_cmd")"
+  current_cores="$(echo "$current_config" | grep -oP '^cores:\s*\K\S+' || echo '?')"
+  current_memory="$(echo "$current_config" | grep -oP '^memory:\s*\K\S+' || echo '?')"
+
+  echo
+  echo "VMID ${vmid} is a ${kind} on ${node}. Planned changes:"
+  [[ -n "$cores" ]] && echo "  cores:  ${current_cores} -> ${cores}"
+  [[ -n "$memory" ]] && echo "  memory: ${current_memory} MB -> ${memory} MB"
+  [[ -n "$grow_disk" ]] && echo "  ${disk_key}: grow by +${grow_disk}G (Proxmox can only grow, not shrink, an existing disk)"
+
+  if [[ "$dry_run" -eq 1 ]]; then
+    echo
+    echo "[dry-run] Nothing was changed."
+    return
+  fi
+
+  echo
+  read -rp "Type the VMID (${vmid}) to confirm these changes: " confirm
+  if [[ "$confirm" != "$vmid" ]]; then
+    echo "Cancelled -- input didn't match ${vmid}."
+    exit 1
+  fi
+
+  local set_cmd="qm set"
+  local resize_cmd="qm resize"
+  [[ "$kind" == "lxc" ]] && set_cmd="pct set" && resize_cmd="pct resize"
+
+  if [[ -n "$cores" || -n "$memory" ]]; then
+    local args=""
+    [[ -n "$cores" ]] && args="${args} --cores ${cores}"
+    [[ -n "$memory" ]] && args="${args} --memory ${memory}"
+    remote "${set_cmd} ${vmid}${args}"
+  fi
+  if [[ -n "$grow_disk" ]]; then
+    remote "${resize_cmd} ${vmid} ${disk_key} +${grow_disk}G"
+  fi
+
+  echo
+  echo "Done. VMID ${vmid} updated."
+}
+
+if [[ "$modify" -eq 1 ]]; then
+  cmd_modify
+  exit 0
+fi
+
+# ============================================================= create mode
+if [[ "$type" != "lxc" && "$type" != "vm" ]]; then
+  echo "ERROR: --type must be 'lxc' or 'vm'." >&2
+  usage >&2
+  exit 1
+fi
+
+platform_prefix="lxc"
+[[ "$type" == "vm" ]] && platform_prefix="proxmox"
+[[ -z "$cores" ]] && cores="$PROXMOX_DEFAULT_CORES"
+[[ -z "$memory" ]] && memory="$PROXMOX_DEFAULT_MEMORY_MB"
+
+# --- discover / resolve the flake target from --host --------------------
+list_hosts() {
+  local target hostname
+  for target in $(nix eval --json --no-use-registries --no-accept-flake-config \
+    "${repo_root}#nixosConfigurations" --apply builtins.attrNames 2>/dev/null \
+    | jq -r --arg p "${platform_prefix}-" '.[] | select(startswith($p))'); do
+    hostname="$(nix eval --raw --no-use-registries --no-accept-flake-config \
+      "${repo_root}#nixosConfigurations.${target}.config.networking.hostName" 2>/dev/null)"
+    printf '  %-12s -> %s\n' "$hostname" "$target"
+  done
+}
+
+if [[ "$do_list" -eq 1 ]]; then
+  echo "Available --host values for --type ${type}:"
+  list_hosts
+  exit 0
+fi
+
+if [[ -z "$host" ]]; then
+  echo "ERROR: --host is required (or use --list to see options)." >&2
+  exit 1
+fi
+
+flake_target=""
+for target in $(nix eval --json --no-use-registries --no-accept-flake-config \
+  "${repo_root}#nixosConfigurations" --apply builtins.attrNames \
+  | jq -r --arg p "${platform_prefix}-" '.[] | select(startswith($p))'); do
+  hn="$(nix eval --raw --no-use-registries --no-accept-flake-config \
+    "${repo_root}#nixosConfigurations.${target}.config.networking.hostName")"
+  if [[ "$hn" == "$host" ]]; then
+    flake_target="$target"
+    break
+  fi
+done
+
+if [[ -z "$flake_target" ]]; then
+  echo "ERROR: no ${platform_prefix}-* target has hostName '${host}'." >&2
+  echo "Available:" >&2
+  list_hosts >&2
+  exit 1
+fi
+
+[[ -z "$name" ]] && name="$flake_target"
+
+# --- refuse to duplicate a host that's already really deployed ----------
+# Checked by hostName, not exact flake target: proxmox-server being
+# deployed also blocks --type lxc --host server, since both would carry
+# the same hosts/server/host.nix identity (hostName, hostId).
+if [[ "$allow_duplicate_host" -eq 0 ]]; then
+  deployed_targets_json="$(nix eval --json --no-use-registries --no-accept-flake-config \
+    --file "${repo_root}/variables.nix" deployedTargets)"
+  for dt in $(echo "$deployed_targets_json" | jq -r '.[]'); do
+    dt_hostname="$(nix eval --raw --no-use-registries --no-accept-flake-config \
+      "${repo_root}#nixosConfigurations.${dt}.config.networking.hostName" 2>/dev/null || true)"
+    if [[ "$dt_hostname" == "$host" ]]; then
+      echo "ERROR: '${host}' already has a real deployment (${dt}, per variables.nix's" >&2
+      echo "deployedTargets). Creating ${flake_target} would share its hostName/hostId --" >&2
+      echo "refusing by default. Pass --allow-duplicate-host if you really mean to spin" >&2
+      echo "up a separate test instance of this host (it'll still get its own distinct" >&2
+      echo "sops key and VMID, never touching ${dt})." >&2
+      exit 1
+    fi
+  done
+fi
+
+echo "Target: ${flake_target} (host=${host}, type=${type}) -> Proxmox resource '${name}'"
+
+# --- make sure this target has a registered host key --------------------
+echo
+echo "==> Ensuring host key exists and is registered..."
+sync_args=("$flake_target")
+[[ "$dry_run" -eq 1 ]] && sync_args+=(--dry-run)
+bash "$sync_keys" "${sync_args[@]}"
+
+# --- VMID: pick one, and refuse to touch anything that already exists ---
+echo
+if [[ -z "$vmid" ]]; then
+  if [[ "$dry_run" -eq 1 ]]; then
+    vmid="<next-free-vmid>"
+    echo "[dry-run] would ask ${node} for the next free VMID (pvesh get /cluster/nextid)"
+  else
+    vmid="$(ssh "$ssh_target" "pvesh get /cluster/nextid" | tr -d '[:space:]')"
+    echo "Auto-assigned VMID: ${vmid}"
+  fi
+else
+  echo "Requested VMID: ${vmid}"
+fi
+
+if [[ "$dry_run" -eq 0 ]]; then
+  # qm/pct status exits non-zero (and prints "does not exist") for a free
+  # ID on that resource type -- but a VMID could exist as the OTHER
+  # resource type (e.g. requested a CT id that's actually a VM), so check
+  # both. Any success here means something is already using this ID --
+  # refuse to go anywhere near it. (Reconfiguring an existing resource is
+  # --modify's job, not this one's.)
+  if ssh "$ssh_target" "qm status ${vmid}" >/dev/null 2>&1 \
+    || ssh "$ssh_target" "pct status ${vmid}" >/dev/null 2>&1; then
+    echo "ERROR: VMID ${vmid} already exists on ${node}. Refusing to touch an" >&2
+    echo "existing resource here -- use --modify to reconfigure it, pick a" >&2
+    echo "different --vmid, or omit it to auto-assign." >&2
+    exit 1
+  fi
+fi
+
+# --- build (or reuse) the image ------------------------------------------
+echo
+local_image=""
+remote_dir=""
+if [[ -n "$image" ]]; then
+  [[ -f "$image" ]] || { echo "ERROR: --image '${image}' not found." >&2; exit 1; }
+  local_image="$image"
+  echo "Using provided image: ${local_image}"
+elif [[ "$type" == "lxc" ]]; then
+  remote_dir="/var/lib/vz/dump"
+  if [[ "$dry_run" -eq 1 ]]; then
+    echo "[dry-run] would build: NIXOS_HOST_KEYS_DIR=${repo_root}/host-keys nix build --impure \\"
+    echo "[dry-run]   .#nixosConfigurations.${flake_target}.config.system.build.tarball"
+    local_image="<built-tarball>"
+  else
+    echo "==> Building LXC tarball for ${flake_target}..."
+    NIXOS_HOST_KEYS_DIR="${repo_root}/host-keys" nix build --impure \
+      --no-use-registries --no-accept-flake-config \
+      ".#nixosConfigurations.${flake_target}.config.system.build.tarball" \
+      --out-link "${repo_root}/result-${flake_target}"
+    local_image="$(find "${repo_root}/result-${flake_target}/tarball" -maxdepth 1 -type f | head -1)"
+    echo "Built: ${local_image}"
+  fi
+else
+  remote_dir="/var/lib/vz/import"
+  if [[ "$dry_run" -eq 1 ]]; then
+    echo "[dry-run] would build: nix build .#nixosConfigurations.${flake_target}.config.system.build.diskoImagesScript"
+    echo "[dry-run] would run:   sudo ./result-${flake_target} \\"
+    echo "[dry-run]                --pre-format-files host-keys/${flake_target}_ssh_host_ed25519_key /etc/ssh/ssh_host_ed25519_key \\"
+    echo "[dry-run]                --pre-format-files host-keys/${flake_target}_ssh_host_ed25519_key.pub /etc/ssh/ssh_host_ed25519_key.pub \\"
+    echo "[dry-run]                --build-memory 2048"
+    local_image="<built-image>.raw"
+  else
+    echo "==> Building Disko image script for ${flake_target}..."
+    nix build --no-use-registries --no-accept-flake-config \
+      ".#nixosConfigurations.${flake_target}.config.system.build.diskoImagesScript" \
+      --out-link "${repo_root}/result-${flake_target}"
+    echo "==> Running it (builds the .raw image in a temporary QEMU VM, needs sudo)..."
+    ( cd "$repo_root" && sudo "./result-${flake_target}" \
+        --pre-format-files "host-keys/${flake_target}_ssh_host_ed25519_key" /etc/ssh/ssh_host_ed25519_key \
+        --pre-format-files "host-keys/${flake_target}_ssh_host_ed25519_key.pub" /etc/ssh/ssh_host_ed25519_key.pub \
+        --build-memory 2048 )
+    local_image="$(find "$repo_root" -maxdepth 1 -name "*.raw" -newer "${repo_root}/result-${flake_target}" | head -1)"
+    if [[ -z "$local_image" ]]; then
+      echo "ERROR: expected a .raw image after the build but didn't find one in ${repo_root}." >&2
+      exit 1
+    fi
+    echo "Built: ${local_image}"
+  fi
+fi
+
+# --- upload ---------------------------------------------------------------
+echo
+remote_path="${remote_dir}/$(basename "${local_image}")"
+if [[ "$dry_run" -eq 1 ]]; then
+  echo "[dry-run] would upload: scp ${local_image} ${ssh_target}:${remote_path}"
+else
+  echo "==> Uploading to ${node}:${remote_path}..."
+  ssh "$ssh_target" "mkdir -p ${remote_dir}"
+  scp "$local_image" "${ssh_target}:${remote_path}"
+fi
+
+# --- create -----------------------------------------------------------------
+echo
+if [[ "$type" == "lxc" ]]; then
+  echo "==> Creating LXC container ${vmid} (${name})..."
+  restore_cmd="pct restore ${vmid} ${remote_path} --storage ${storage} --hostname ${name} --cores ${cores} --memory ${memory} --net0 name=eth0,bridge=${bridge},ip=dhcp"
+  [[ -n "$disk_size" ]] && restore_cmd="${restore_cmd} --rootfs ${storage}:${disk_size}"
+  remote "$restore_cmd"
+  remote "pct start ${vmid}"
+else
+  echo "==> Creating VM ${vmid} (${name})..."
+  # pre-enrolled-keys=0 disables OVMF's Secure Boot key pre-enrollment --
+  # required, or systemd-boot (unsigned) can't be trusted by the firmware.
+  remote "qm create ${vmid} --name ${name} --memory ${memory} --cores ${cores} \
+--net0 virtio,bridge=${bridge} --bios ovmf --machine q35 --scsihw virtio-scsi-pci \
+--efidisk0 ${storage}:1,efitype=4m,pre-enrolled-keys=0"
+
+  if [[ "$dry_run" -eq 1 ]]; then
+    echo "[dry-run] ssh ${ssh_target} -- qm importdisk ${vmid} ${remote_path} ${storage}"
+    echo "[dry-run] (would parse the resulting disk identifier from that output)"
+    echo "[dry-run] ssh ${ssh_target} -- qm set ${vmid} --scsi0 ${storage}:<parsed-disk-id>"
+  else
+    importdisk_output="$(ssh "$ssh_target" "qm importdisk ${vmid} ${remote_path} ${storage}")"
+    echo "$importdisk_output"
+    disk_id="$(echo "$importdisk_output" | grep -oP "(?<=Successfully imported disk as ')[^']+" | sed 's/^unused[0-9]*://')"
+    if [[ -z "$disk_id" ]]; then
+      echo "ERROR: couldn't parse the imported disk identifier from qm importdisk's output above." >&2
+      echo "The VM shell (${vmid}) and imported disk both exist -- finish attaching it by hand:" >&2
+      echo "  ssh ${ssh_target} -- qm set ${vmid} --scsi0 ${storage}:<disk-id-from-output-above>" >&2
+      echo "  ssh ${ssh_target} -- qm set ${vmid} --boot order=scsi0" >&2
+      exit 1
+    fi
+    remote "qm set ${vmid} --scsi0 ${disk_id}"
+  fi
+  remote "qm set ${vmid} --boot order=scsi0"
+  remote "qm start ${vmid}"
+fi
+
+echo
+if [[ "$dry_run" -eq 1 ]]; then
+  echo "[dry-run] Nothing was built, uploaded, or created."
+else
+  echo "Done. ${name} (VMID ${vmid}) should be booting on ${node}."
+fi

scripts/env.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+# Shared config for scripts/*.sh. Source this instead of hardcoding a
+# second copy of these values in every script:
+#   source "$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/env.sh"
+# Every variable can still be overridden per-invocation via the
+# environment (e.g. PROXMOX_STORAGE=tank-nvme ./scripts/create-proxmox-resource.sh ...)
+# since each one only sets a default if unset.
+
+# SSH-reachable Proxmox node that scripts/create-proxmox-resource.sh runs
+# pct/qm on. Matches the Proxmox web UI hostname already used in
+# hosts/nixos/home.nix's desktop shortcuts (pve.<homeDomain> from
+# variables.nix) -- change this if that's not actually reachable over SSH,
+# or if you're targeting a different node in a multi-node cluster.
+: "${PROXMOX_HOST:=pve.sweet.home}"
+: "${PROXMOX_SSH_USER:=root}"
+
+# Storage pool names -- Proxmox's own stock-install defaults, but this
+# varies a lot by setup (ZFS pool name, custom LVM-thin volume, etc.).
+# Verify with `pvesm status` on the node and correct these if wrong.
+: "${PROXMOX_STORAGE:=local-lvm}"     # VM disks / CT rootfs
+: "${PROXMOX_ISO_STORAGE:=local}"     # uploaded images/ISOs/CT templates
+
+: "${PROXMOX_BRIDGE:=vmbr0}"
+
+# Fallback resource sizing when a script doesn't get --cores/--memory.
+: "${PROXMOX_DEFAULT_CORES:=2}"
+: "${PROXMOX_DEFAULT_MEMORY_MB:=2048}"
+
+export PROXMOX_HOST PROXMOX_SSH_USER PROXMOX_STORAGE PROXMOX_ISO_STORAGE \
+  PROXMOX_BRIDGE PROXMOX_DEFAULT_CORES PROXMOX_DEFAULT_MEMORY_MB

scripts/lib/sync-host-keys-edit-sops.py

@@ -0,0 +1,180 @@
+#!/usr/bin/env python3
+# Companion to scripts/sync-host-keys.sh. Applies a set of additive edits
+# to .sops.yaml via targeted line insertion -- not a full YAML parse and
+# re-serialize -- so every untouched byte of the file is guaranteed to stay
+# exactly as it was (a full round-trip through a generic YAML library was
+# tested and silently reformatted the whole file's indentation style).
+#
+# Reads a JSON edit plan from stdin:
+#   {
+#     "add_keys": [{"host": "lxc-server", "age_key": "age1..."}],
+#     "add_aliases": [{"host": "lxc-server", "basename": "common.yaml"}],
+#     "remove_keys": ["lxc-server"],
+#     "remove_aliases_for_hosts": ["lxc-server"]
+#   }
+# Idempotent: an anchor or alias that's already present/absent is left
+# alone -- adding what's already there, or removing what's already gone,
+# is a no-op rather than an error.
+# Prints a JSON summary of what actually changed to stdout, so the caller
+# knows which secrets/*.yaml files need `sops updatekeys` and which don't.
+import json
+import re
+import sys
+
+KEY_LINE_RE = re.compile(r"^  - &\S+ age1")
+
+
+def add_keys(lines, add_keys):
+    existing_anchors = set()
+    for line in lines:
+        m = re.match(r"^  - &(\S+) age1", line)
+        if m:
+            existing_anchors.add(m.group(1))
+
+    new = [e for e in add_keys if e["host"] not in existing_anchors]
+    if not new:
+        return lines, []
+
+    last_idx = None
+    for i, line in enumerate(lines):
+        if KEY_LINE_RE.match(line):
+            last_idx = i
+    if last_idx is None:
+        print("ERROR: no '  - &<name> age1...' line found under keys: in .sops.yaml", file=sys.stderr)
+        sys.exit(1)
+
+    insert = [f"  - &{e['host']} {e['age_key']}\n" for e in new]
+    lines = lines[: last_idx + 1] + insert + lines[last_idx + 1 :]
+    return lines, [e["host"] for e in new]
+
+
+def add_aliases(lines, add_aliases):
+    changed_files = []
+    for e in add_aliases:
+        host = e["host"]
+        basename = e["basename"]
+        target = "path_regex: secrets/" + basename.replace(".", r"\.") + "$"
+
+        rule_start = None
+        for i, line in enumerate(lines):
+            if target in line:
+                rule_start = i
+                break
+        if rule_start is None:
+            print(
+                f"WARNING: no creation_rule for secrets/{basename} in .sops.yaml "
+                f"(needed by {host}) -- add one manually, then re-run.",
+                file=sys.stderr,
+            )
+            continue
+
+        rule_end = len(lines)
+        for i in range(rule_start + 1, len(lines)):
+            if re.match(r"^  - path_regex:", lines[i]):
+                rule_end = i
+                break
+
+        block = lines[rule_start:rule_end]
+        if any(re.search(r"\*" + re.escape(host) + r"\s*$", line) for line in block):
+            continue  # already present
+
+        last_alias_idx = None
+        last_alias_indent = None
+        for i in range(rule_start, rule_end):
+            m = re.match(r"^(\s*)- \*\S+\s*$", lines[i])
+            if m:
+                last_alias_idx = i
+                last_alias_indent = m.group(1)
+        if last_alias_idx is None:
+            print(
+                f"WARNING: creation_rule for secrets/{basename} has no existing "
+                f"'- *alias' line to anchor the insertion point -- add {host} manually.",
+                file=sys.stderr,
+            )
+            continue
+
+        new_line = f"{last_alias_indent}- *{host}\n"
+        lines = lines[: last_alias_idx + 1] + [new_line] + lines[last_alias_idx + 1 :]
+        changed_files.append(basename)
+    return lines, changed_files
+
+
+def remove_keys(lines, hosts):
+    hosts = set(hosts)
+    removed = []
+    kept = []
+    for line in lines:
+        m = re.match(r"^  - &(\S+) age1", line)
+        if m and m.group(1) in hosts:
+            removed.append(m.group(1))
+            continue
+        kept.append(line)
+    return kept, removed
+
+
+def remove_aliases_for_hosts(lines, hosts):
+    hosts = set(hosts)
+    if not hosts:
+        return lines, []
+
+    changed_files = []
+    result = []
+    current_basename = None
+    current_block_changed = False
+
+    def flush():
+        if current_block_changed and current_basename:
+            changed_files.append(current_basename)
+
+    for line in lines:
+        if re.match(r"^  - path_regex:", line):
+            flush()
+            current_block_changed = False
+            m = re.search(r"path_regex: secrets/(.+)\$", line)
+            current_basename = m.group(1).replace(r"\.", ".") if m else None
+            result.append(line)
+            continue
+
+        if current_basename is not None and any(
+            re.search(r"\*" + re.escape(h) + r"\s*$", line) for h in hosts
+        ):
+            current_block_changed = True
+            continue  # drop this alias line
+
+        result.append(line)
+
+    flush()
+    return result, changed_files
+
+
+def main():
+    sops_path = sys.argv[1]
+    edits = json.load(sys.stdin)
+
+    with open(sops_path) as f:
+        lines = f.readlines()
+
+    lines, added_keys = add_keys(lines, edits.get("add_keys", []))
+    lines, added_alias_files = add_aliases(lines, edits.get("add_aliases", []))
+    lines, removed_keys = remove_keys(lines, edits.get("remove_keys", []))
+    lines, removed_alias_files = remove_aliases_for_hosts(
+        lines, edits.get("remove_aliases_for_hosts", [])
+    )
+
+    with open(sops_path, "w") as f:
+        f.writelines(lines)
+
+    changed_files = sorted(set(added_alias_files) | set(removed_alias_files))
+    json.dump(
+        {
+            "added_keys": added_keys,
+            "removed_keys": removed_keys,
+            "changed_secrets_files": changed_files,
+        },
+        sys.stdout,
+    )
+    print()
+
+
+if __name__ == "__main__":
+    main()

scripts/prepare-host-key.sh

@@ -1,9 +1,13 @@
 #!/usr/bin/env bash
-# Generates a new machine's SSH host key ahead of installing it, so
-# sops-nix has something to derive an age key from before the target
-# ever boots.
+# Generates a new machine's SSH host key by an arbitrary name, before it
+# necessarily has a flake target yet -- prints the .sops.yaml snippet to
+# add by hand. For any host that already has a flake target,
+# scripts/sync-host-keys.sh <target> does this same job plus the
+# .sops.yaml/key_groups registration and re-encryption automatically; use
+# this script only to pre-generate a key ahead of adding the flake target
+# itself.
 #
-# Why this is needed: sops-nix derives each host's decryption key from
+# Why a host key is needed at all: sops-nix derives each host's decryption key from
 # its own /etc/ssh/ssh_host_ed25519_key at *activation* time, but that
 # activation runs before systemd would otherwise generate this key on
 # first boot (sshd-keygen is a normal systemd service gated behind

scripts/sync-host-keys.sh

@@ -0,0 +1,437 @@
+#!/usr/bin/env bash
+# Manages host-keys/ + .sops.yaml + secrets/*.yaml recipients together, so
+# a flake target's SSH host key and its sops registration never drift out
+# of sync with each other or with the flake itself.
+#
+#   sync-host-keys.sh --all                Generate/register every flake
+#                                           target missing a key.
+#   sync-host-keys.sh <target>              Same, for just one target.
+#   sync-host-keys.sh --remove              Interactively remove one
+#                                           locally-managed key.
+#   sync-host-keys.sh --regenerate-all-keys Remove and freshly regenerate
+#                                           every locally-managed key.
+#
+# "Generate/register" is idempotent and additive only: an existing
+# host-keys/ file is never touched, and .sops.yaml only ever gains an
+# anchor/alias it doesn't already have -- safe to re-run any time, e.g.
+# right after adding a new host to flake.nix.
+#
+# --remove and --regenerate-all-keys only ever operate on anchors that have
+# a corresponding host-keys/<name>_ssh_host_ed25519_key file. Anchors
+# without one (&admin, and any anchor for an already-deployed host whose
+# real /etc/ssh key was registered by hand, e.g. &docker/&server/&nix-cache
+# today) are never listed, removed, or regenerated -- this tooling only
+# ever touches keys it itself manages.
+set -euo pipefail
+
+repo_root="$(cd "$(dirname "$0")/.." && pwd)"
+sops_yaml="${repo_root}/.sops.yaml"
+keydir="${repo_root}/host-keys"
+editor="${repo_root}/scripts/lib/sync-host-keys-edit-sops.py"
+
+mkdir -p "$keydir"
+
+usage() {
+  cat <<EOF
+Usage: $0 --all [--dry-run]
+       $0 <flake-target> [--dry-run]
+       $0 --remove [--dry-run]
+       $0 --regenerate-all-keys [--dry-run]
+
+  --all                    Generate + register a host key for every flake
+                            target that's missing one.
+  <flake-target>            Same, for just one target (e.g. lxc-server).
+                            Reports if it already has one.
+  --remove                  Interactively pick one locally-managed key to
+                            remove from .sops.yaml and host-keys/.
+  --regenerate-all-keys     Remove every locally-managed key and generate
+                            fresh replacements for every current flake
+                            target. Destructive -- requires typed
+                            confirmation.
+  --dry-run                 Combine with any of the above: print what would
+                            change (host-keys/ files, .sops.yaml anchors and
+                            key_groups, which secrets/*.yaml would be
+                            re-encrypted) without touching anything. No keys
+                            generated, no files written, no sops calls,
+                            no prompts for confirmation.
+EOF
+}
+
+# --- step 0: make sure we can actually decrypt anything at all -------------
+#
+# Registering a host means editing .sops.yaml and then running
+# `sops updatekeys`, which has to decrypt each secrets file with an
+# existing recipient's key before it can re-encrypt it for the new one.
+# Check this before doing anything else, the same order sops/age itself
+# resolves a usable key in: SOPS_AGE_KEY (inline), then SOPS_AGE_KEY_FILE,
+# then the XDG default path.
+ensure_admin_decrypt_key() {
+  if [[ -n "${SOPS_AGE_KEY:-}" ]]; then
+    echo "Using SOPS_AGE_KEY from the environment."
+    return
+  fi
+
+  local key_file="${SOPS_AGE_KEY_FILE:-${XDG_CONFIG_HOME:-$HOME/.config}/sops/age/keys.txt}"
+
+  if [[ -s "$key_file" ]]; then
+    echo "Found existing sops age key at ${key_file}."
+    return
+  fi
+
+  if [[ "$dry_run" -eq 1 ]]; then
+    echo "[dry-run] No sops age decryption key found (checked \$SOPS_AGE_KEY, \$SOPS_AGE_KEY_FILE, ${key_file})."
+    echo "[dry-run] Would generate a new one here -- continuing the dry run without one; any"
+    echo "[dry-run] 'would re-encrypt' output below couldn't actually run for real yet."
+    return
+  fi
+
+  echo "No sops age decryption key found (checked \$SOPS_AGE_KEY, \$SOPS_AGE_KEY_FILE, ${key_file})."
+  echo "Generating a new one at ${key_file}..."
+  mkdir -p "$(dirname "$key_file")"
+  nix-shell -p age --run "age-keygen -o '${key_file}'" 2>&1 | grep -v "^Public key:" || true
+  local new_pub
+  new_pub="$(nix-shell -p age --run "age-keygen -y '${key_file}'")"
+
+  cat <<EOF
+
+A brand-new age key was just generated -- it cannot decrypt anything that
+already exists in secrets/*.yaml, since nothing was ever encrypted for it.
+That trust can't be bootstrapped automatically (nobody can decrypt a file
+for a recipient that didn't exist when it was last encrypted).
+
+To actually use this key:
+  1. Have someone who currently CAN decrypt replace the &admin entry in
+     .sops.yaml with this public key:
+       ${new_pub}
+  2. They re-encrypt every secrets/*.yaml:
+       sops updatekeys --yes secrets/common.yaml
+       sops updatekeys --yes secrets/nix-cache.yaml
+       sops updatekeys --yes secrets/server.yaml
+  3. Re-run this script.
+
+Exiting without making any other changes.
+EOF
+  exit 1
+}
+
+discover_targets() {
+  nix eval --json --no-use-registries --no-accept-flake-config \
+    "${repo_root}#nixosConfigurations" --apply builtins.attrNames \
+  | jq -r '.[] | select(. != "installer")'
+  # installer is the one nixosConfigurations target that doesn't import
+  # sops-nix at all (see CLAUDE.md's "Security Notes" -- hardcoded login
+  # password instead) -- config.sops.secrets doesn't exist for it.
+}
+
+locally_managed_hosts() {
+  for f in "$keydir"/*_ssh_host_ed25519_key.pub; do
+    [[ -e "$f" ]] || continue
+    basename "$f" _ssh_host_ed25519_key.pub
+  done
+}
+
+add_keys_json="[]"
+add_aliases_json="[]"
+dry_run=0
+
+queue_host_sync() {
+  local host="$1"
+  local keyfile="${keydir}/${host}_ssh_host_ed25519_key"
+  local has_local_key=0 has_anchor=0
+  [[ -f "$keyfile" ]] && has_local_key=1
+  grep -qE "^  - &${host} age1" "$sops_yaml" && has_anchor=1
+
+  if [[ "$has_local_key" -eq 0 && "$has_anchor" -eq 1 ]]; then
+    echo "SKIP ${host}: .sops.yaml already has an &${host} anchor, but"
+    echo "     host-keys/${host}_ssh_host_ed25519_key is missing locally."
+    echo "     Not generating a replacement -- it wouldn't match whatever's"
+    echo "     already registered (and possibly deployed). Remove the"
+    echo "     &${host} line from .sops.yaml first if you really want a"
+    echo "     fresh key, then re-run."
+    return 1
+  fi
+
+  if [[ "$has_local_key" -eq 0 ]]; then
+    if [[ "$dry_run" -eq 1 ]]; then
+      echo "[dry-run] ${host}: would generate host key"
+    else
+      echo "==> ${host}: generating host key"
+      nix-shell -p openssh --run "ssh-keygen -t ed25519 -N '' -C '${host}' -f '${keyfile}'" >/dev/null
+    fi
+  else
+    echo "==> ${host}: host key already present"
+  fi
+
+  if [[ "$has_anchor" -eq 0 ]]; then
+    local age_pub
+    if [[ "$dry_run" -eq 1 ]]; then
+      age_pub="dry-run-placeholder-not-a-real-key"
+    else
+      age_pub="$(nix-shell -p ssh-to-age --run "ssh-to-age -i '${keyfile}.pub'")"
+    fi
+    add_keys_json="$(jq --arg host "$host" --arg key "$age_pub" \
+      '. + [{host: $host, age_key: $key}]' <<<"$add_keys_json")"
+  fi
+
+  echo "==> ${host}: checking which secrets files it references"
+  local basenames
+  mapfile -t basenames < <(
+    nix eval --json --no-use-registries --no-accept-flake-config \
+      "${repo_root}#nixosConfigurations.${host}.config.sops.secrets" \
+      --apply 'builtins.mapAttrs (n: v: baseNameOf v.sopsFile)' \
+    | jq -r '[.[]] | unique | .[]'
+  )
+  local basename
+  for basename in "${basenames[@]}"; do
+    add_aliases_json="$(jq --arg host "$host" --arg basename "$basename" \
+      '. + [{host: $host, basename: $basename}]' <<<"$add_aliases_json")"
+  done
+}
+
+# In dry-run, this runs the exact same edit logic (so idempotency/what's-
+# actually-new is determined for real, not guessed) but against a scratch
+# copy of .sops.yaml that's discarded afterward -- the real file is never
+# opened for writing, and `sops updatekeys` never runs.
+apply_edit_plan() {
+  local plan="$1"
+  local target="$sops_yaml"
+  local tmpfile=""
+  if [[ "$dry_run" -eq 1 ]]; then
+    tmpfile="$(mktemp)"
+    cp "$sops_yaml" "$tmpfile"
+    target="$tmpfile"
+  fi
+
+  local result
+  result="$(echo "$plan" | nix-shell -p python3 --run "python3 '${editor}' '${target}'")"
+  [[ -n "$tmpfile" ]] && rm -f "$tmpfile"
+
+  local added removed changed
+  added="$(jq -r '.added_keys[]?' <<<"$result")"
+  removed="$(jq -r '.removed_keys[]?' <<<"$result")"
+  changed="$(jq -r '.changed_secrets_files[]?' <<<"$result")"
+
+  if [[ -z "$added" && -z "$removed" && -z "$changed" ]]; then
+    echo "Nothing changed in .sops.yaml."
+    return
+  fi
+
+  local prefix=""
+  [[ "$dry_run" -eq 1 ]] && prefix="[dry-run] would "
+
+  [[ -n "$added" ]] && echo "${prefix}Add .sops.yaml anchors: $(tr '\n' ' ' <<<"$added")"
+  [[ -n "$removed" ]] && echo "${prefix}Remove .sops.yaml anchors: $(tr '\n' ' ' <<<"$removed")"
+
+  if [[ -n "$changed" ]]; then
+    if [[ "$dry_run" -eq 1 ]]; then
+      echo "[dry-run] would re-encrypt:"
+      while IFS= read -r basename; do
+        [[ -z "$basename" ]] && continue
+        echo "  secrets/${basename}"
+      done <<<"$changed"
+    else
+      echo "Re-encrypting affected secrets files..."
+      while IFS= read -r basename; do
+        [[ -z "$basename" ]] && continue
+        echo "==> secrets/${basename}"
+        nix-shell -p sops --run "sops updatekeys --yes '${repo_root}/secrets/${basename}'"
+      done <<<"$changed"
+    fi
+  fi
+}
+
+flush_additions() {
+  if [[ "$add_keys_json" == "[]" && "$add_aliases_json" == "[]" ]]; then
+    echo "Nothing to do -- every requested target already has a fully registered host key."
+    return
+  fi
+  echo
+  echo "Applying .sops.yaml edits..."
+  local plan
+  plan="$(jq -n --argjson add_keys "$add_keys_json" --argjson add_aliases "$add_aliases_json" \
+    '{add_keys: $add_keys, add_aliases: $add_aliases}')"
+  apply_edit_plan "$plan"
+  echo
+  if [[ "$dry_run" -eq 1 ]]; then
+    echo "[dry-run] Nothing was changed. Re-run without --dry-run to apply this."
+  else
+    echo "Done. Review the .sops.yaml / secrets/*.yaml diff, then commit and push --"
+    echo "the flake build the installer uses has to see the new recipient(s) before"
+    echo "any of these hosts can decrypt their secrets on first boot."
+  fi
+}
+
+cmd_all() {
+  echo "Discovering flake targets..."
+  local targets
+  mapfile -t targets < <(discover_targets)
+  local host
+  for host in "${targets[@]}"; do
+    queue_host_sync "$host" || true
+  done
+  flush_additions
+}
+
+cmd_target() {
+  local host="$1"
+  local targets
+  mapfile -t targets < <(discover_targets)
+  if ! printf '%s\n' "${targets[@]}" | grep -qxF "$host"; then
+    echo "ERROR: '${host}' is not a current nixosConfigurations target." >&2
+    echo "Current targets:" >&2
+    printf '  %s\n' "${targets[@]}" >&2
+    exit 1
+  fi
+  queue_host_sync "$host" || exit 1
+  flush_additions
+}
+
+cmd_remove() {
+  local hosts
+  mapfile -t hosts < <(locally_managed_hosts)
+  if [[ "${#hosts[@]}" -eq 0 ]]; then
+    echo "No locally-managed keys in host-keys/ -- nothing to remove."
+    return
+  fi
+
+  echo "Locally-managed keys:"
+  local i=1 host
+  for host in "${hosts[@]}"; do
+    local registered="not registered in .sops.yaml"
+    grep -qE "^  - &${host} age1" "$sops_yaml" && registered="registered in .sops.yaml"
+    printf '  %d) %s (%s)\n' "$i" "$host" "$registered"
+    i=$((i + 1))
+  done
+
+  local choice
+  read -rp "Remove which one? (number, or blank to cancel): " choice
+  if [[ -z "$choice" ]]; then
+    echo "Cancelled."
+    return
+  fi
+  if ! [[ "$choice" =~ ^[0-9]+$ ]] || (( choice < 1 || choice > ${#hosts[@]} )); then
+    echo "ERROR: invalid selection." >&2
+    exit 1
+  fi
+  local target="${hosts[$((choice - 1))]}"
+
+  if [[ "$dry_run" -ne 1 ]]; then
+    read -rp "Really remove '${target}'? Its host-keys/ files will be deleted and it will lose access to every secrets file it can currently decrypt. (y/N): " confirm
+    if [[ ! "$confirm" =~ ^[Yy]$ ]]; then
+      echo "Cancelled."
+      return
+    fi
+  fi
+
+  local plan
+  plan="$(jq -n --arg host "$target" \
+    '{remove_keys: [$host], remove_aliases_for_hosts: [$host]}')"
+  apply_edit_plan "$plan"
+
+  if [[ "$dry_run" -eq 1 ]]; then
+    echo "[dry-run] would delete host-keys/${target}_ssh_host_ed25519_key(.pub)."
+    echo "[dry-run] Nothing was changed. Re-run without --dry-run to apply this."
+  else
+    rm -f "${keydir}/${target}_ssh_host_ed25519_key" "${keydir}/${target}_ssh_host_ed25519_key.pub"
+    echo "Removed host-keys/${target}_ssh_host_ed25519_key(.pub)."
+    echo
+    echo "Review the diff, then commit and push."
+  fi
+}
+
+cmd_regenerate_all() {
+  local hosts
+  mapfile -t hosts < <(locally_managed_hosts)
+  if [[ "${#hosts[@]}" -eq 0 ]]; then
+    echo "No locally-managed keys in host-keys/ -- nothing to regenerate."
+    return
+  fi
+
+  echo "This will remove and freshly regenerate ALL locally-managed keys:"
+  printf '  %s\n' "${hosts[@]}"
+  echo
+  echo "Every host above will need its new key baked into a rebuilt install"
+  echo "image/tarball before it can decrypt secrets again."
+
+  if [[ "$dry_run" -ne 1 ]]; then
+    read -rp "Type REGENERATE to confirm: " confirm
+    if [[ "$confirm" != "REGENERATE" ]]; then
+      echo "Cancelled."
+      return
+    fi
+  fi
+
+  echo
+  local hosts_json
+  hosts_json="$(printf '%s\n' "${hosts[@]}" | jq -R . | jq -s .)"
+  local plan
+  plan="$(jq -n --argjson hosts "$hosts_json" \
+    '{remove_keys: $hosts, remove_aliases_for_hosts: $hosts}')"
+  apply_edit_plan "$plan"
+
+  if [[ "$dry_run" -eq 1 ]]; then
+    echo "[dry-run] would delete ${#hosts[@]} host-keys/ file pair(s)."
+    echo "[dry-run] would then generate fresh replacements for the same hosts"
+    echo "[dry-run] (not simulated further here -- run without --dry-run, or"
+    echo "[dry-run] preview a specific target with: $0 <target> --dry-run)."
+    echo
+    echo "[dry-run] Nothing was changed. Re-run without --dry-run to apply this."
+    return
+  fi
+
+  echo "Removing existing keys..."
+  local host
+  for host in "${hosts[@]}"; do
+    rm -f "${keydir}/${host}_ssh_host_ed25519_key" "${keydir}/${host}_ssh_host_ed25519_key.pub"
+  done
+  echo "Removed ${#hosts[@]} host-keys/ file pair(s)."
+
+  echo
+  echo "Regenerating fresh keys for every current flake target..."
+  cmd_all
+}
+
+main() {
+  local args=()
+  local arg
+  for arg in "$@"; do
+    if [[ "$arg" == "--dry-run" ]]; then
+      dry_run=1
+    else
+      args+=("$arg")
+    fi
+  done
+  set -- "${args[@]+"${args[@]}"}"
+
+  if [[ "$dry_run" -eq 1 ]]; then
+    echo "[dry-run] no changes will be made"
+    echo
+  fi
+
+  ensure_admin_decrypt_key
+
+  case "${1:-}" in
+    --all)
+      cmd_all
+      ;;
+    --remove)
+      cmd_remove
+      ;;
+    --regenerate-all-keys)
+      cmd_regenerate_all
+      ;;
+    -h | --help | "")
+      usage
+      ;;
+    --*)
+      echo "Unknown option: $1" >&2
+      usage >&2
+      exit 1
+      ;;
+    *)
+      cmd_target "$1"
+      ;;
+  esac
+}
+
+main "$@"

variables.nix

@@ -146,4 +146,21 @@
     maxSize = "100M"; # rotate once a log file exceeds this size
     keep = 20; # number of rotated logs to retain before deleting the oldest
   };
+
+  # Flake targets with a real, currently-running deployment somewhere —
+  # matches README.md's Hosts table "(real, deployed)" annotations; update
+  # both together. Not consumed by any NixOS module (nothing in the actual
+  # system config should behave differently because of this) — it's read
+  # by scripts/create-proxmox-resource.sh to refuse creating a same-identity
+  # duplicate of an already-deployed host (shared hostName/hostId) unless
+  # you explicitly pass --allow-duplicate-host.
+  deployedTargets = [
+    "linode-minimal"
+    "proxmox-minimal"
+    "proxmox-nix-cache"
+    "proxmox-server"
+    "proxmox-docker"
+    "proxmox-gui"
+    "proxmox-pxe-boot"
+  ];
 }