Choose add-or-replace when installing ProxUI's SSH key

app.py

@@ -6732,32 +6732,50 @@ def _termproxy_open(
     )
 
 
-def _install_key_command(pub_line: str) -> str:
+def _install_key_command(pub_line: str, replace: bool = False) -> str:
     """Idempotent shell to put ProxUI's pubkey in root's authorized_keys.
 
-    Removes any previous proxui-snippet@ lines first so re-running is clean.
+    replace=False (default): remove only *this* instance's own key (matched by
+    its key material) before appending it, so re-running is idempotent while
+    leaving other ProxUI instances' keys in place — multiple instances coexist.
+
+    replace=True: remove every prior proxui-snippet@ key (all ProxUI instances)
+    before adding this one, e.g. to clean up keys from decommissioned instances.
     """
     q = shlex.quote(pub_line)
+    if replace:
+        # Drop every ProxUI key regardless of which instance installed it.
+        filter_cmd = "grep -v 'proxui-snippet@' /root/.ssh/authorized_keys"
+    else:
+        # Drop only our own key (by its unique key material), keep the rest.
+        parts = pub_line.split()
+        key_material = parts[1] if len(parts) >= 2 else pub_line
+        filter_cmd = f"grep -vF {shlex.quote(key_material)} /root/.ssh/authorized_keys"
     return (
         "mkdir -p /root/.ssh && chmod 700 /root/.ssh && "
         "touch /root/.ssh/authorized_keys && "
-        "grep -v 'proxui-snippet@' /root/.ssh/authorized_keys > /root/.ssh/.proxui_ak.tmp 2>/dev/null || true && "
+        f"{filter_cmd} > /root/.ssh/.proxui_ak.tmp 2>/dev/null || true && "
         f"printf '%s\\n' {q} >> /root/.ssh/.proxui_ak.tmp && "
         "cat /root/.ssh/.proxui_ak.tmp > /root/.ssh/authorized_keys && "
         "rm -f /root/.ssh/.proxui_ak.tmp && chmod 600 /root/.ssh/authorized_keys && "
         "echo PROXUI_INSTALLED"
     )
 
 
-def _provision_ssh_key(node: str, root_password: str | None = None) -> dict:
+def _provision_ssh_key(
+    node: str, root_password: str | None = None, replace: bool = False
+) -> dict:
     """Install ProxUI's public key into root's authorized_keys on `node`.
 
     Prefers SSH-as-root-with-password when port 22 is open; otherwise drives the
     node Shell (termproxy). Then verifies key-based SFTP works and detects whether
     root's authorized_keys is cluster-shared (pmxcfs). Returns a status dict.
+
+    replace=True removes other ProxUI instances' keys too (see
+    _install_key_command); the default preserves them.
     """
     _priv, pub = _ensure_ssh_key()
-    install_cmd = _install_key_command(pub)
+    install_cmd = _install_key_command(pub, replace=replace)
 
     if _ssh_port_open(node) and root_password:
         client = _ssh_connect_root_password(node, root_password)
@@ -7172,18 +7190,20 @@ def api_snippets_ssh_status():
 def api_snippets_ssh_setup():
     """Generate (if needed) and install ProxUI's public key into root's authorized_keys.
 
-    Body: { node, root_password? }. root_password is required unless the API user
-    is root@pam (passwordless node Shell).
+    Body: { node, root_password?, replace? }. root_password is required unless
+    the API user is root@pam (passwordless node Shell). replace=true also removes
+    other ProxUI instances' keys; the default keeps them.
     """
     data = request.get_json() or {}
     node = data.get("node")
     root_password = data.get("root_password") or None
+    replace = bool(data.get("replace"))
     if not node:
         return jsonify({"error": "node is required"}), 400
     if not get_proxmox_connection(node, auto_renew=True):
         return jsonify({"error": "Node not found"}), 404
     try:
-        result = _provision_ssh_key(node, root_password=root_password)
+        result = _provision_ssh_key(node, root_password=root_password, replace=replace)
         result["success"] = True
         result["message"] = (
             "SSH key installed. Snippet writes will use SFTP as root."

templates/vm_edit.html

@@ -686,6 +686,17 @@ <h5 class="mb-0"><i class="bi bi-cloud-fill"></i> Cloud-Init</h5>
                             <div x-show="ssh.root_pam" class="text-muted mt-1">
                                 This cluster uses root@pam — the node console can install the key without a password.
                             </div>
+                            <div class="mt-2">
+                                <div class="form-text small mb-1">If other ProxUI instances have already installed a key here:</div>
+                                <div class="form-check form-check-inline">
+                                    <input class="form-check-input" type="radio" id="keyModeAdd" value="add" x-model="keyMode">
+                                    <label class="form-check-label small" for="keyModeAdd">Keep them, add this key</label>
+                                </div>
+                                <div class="form-check form-check-inline">
+                                    <input class="form-check-input" type="radio" id="keyModeReplace" value="replace" x-model="keyMode">
+                                    <label class="form-check-label small" for="keyModeReplace">Replace all ProxUI keys with this one</label>
+                                </div>
+                            </div>
                             <button class="btn btn-sm btn-primary mt-2" @click="setupAccess()" :disabled="setupBusy">
                                 <span x-show="setupBusy" class="spinner-border spinner-border-sm me-1"></span>
                                 <i x-show="!setupBusy" class="bi bi-key"></i> Install key
@@ -2987,7 +2998,7 @@ <h5 class="modal-title">Attach ISO Image</h5>
     regenBusy: false,
     // Access / storage setup
     ssh: { checked: false, sftp_ok: false, root_pam: false, pubkey: '' },
-    showSetup: false, showPubkey: false, rootPassword: '',
+    showSetup: false, showPubkey: false, rootPassword: '', keyMode: 'add',
     setupBusy: false, setupMsg: '', setupOk: false,
 
     // True when a custom "user" snippet is attached: Proxmox then ignores the
@@ -3043,7 +3054,7 @@ <h5 class="modal-title">Attach ISO Image</h5>
     async setupAccess() {
       this.setupBusy = true; this.setupMsg = '';
       try {
-        const body = { node };
+        const body = { node, replace: this.keyMode === 'replace' };
         if (!this.ssh.root_pam && this.rootPassword) body.root_password = this.rootPassword;
         const r = await ProxUtils.apiJson(`/api/snippets/ssh/setup`, {
           method: 'POST', headers: { 'Content-Type': 'application/json' },