Document deferred Cerberus management node plan

AGENTS.md

@@ -225,6 +225,41 @@ scheduled retention prune and monthly scrub remain runtime checks.
   after the storage and backup layers are validated; do not make either a dependency of the Atlas
   baseline.
 
+## Cerberus Management Node (Deferred)
+`cerberus` is postponed until the office in the new house is physically set up. It is not an inventory
+host and this section is a design and implementation backlog, not authorization to provision it early.
+
+The planned node is a Lenovo ThinkCentre M700 Tiny with an Intel Core i3-6100T, 8 GB RAM, a 256 GB SSD,
+and native 1 Gbps Ethernet. It will connect to a multi-input KVM switch using a passive DisplayPort-to-HDMI
+cable, sharing the monitor and peripherals with Ikaros. Fedora Sericea (immutable Fedora with the Sway
+Wayland compositor) is the intended OS. Cerberus is an isolated management plane: a dedicated Toolbox
+environment will run Ansible for future `uranus` cluster provisioning. Rootless Podman will host Grafana,
+Prometheus, and Loki. The 256 GB local SSD is the hot tier retaining metrics and logs for 30 days; scheduled,
+validated exports of older historical data will use a dedicated Atlas NFS dataset as cold storage.
+
+### Implementation plan
+- [ ] Confirm the office, KVM switch, passive DisplayPort-to-HDMI path, shared monitor/peripherals, and native
+  1 Gbps Ethernet are physically operational before adding Cerberus to inventory.
+- [ ] Install and update Fedora Sericea with Sway; document the immutable-host lifecycle and keep host changes
+  declarative rather than treating the base OS as a mutable workstation.
+- [ ] Model Cerberus as its own host with independent platform, role, desktop, network, and storage inputs;
+  do not repurpose Ikaros variables or make it a Uranus cluster member.
+- [ ] Provision an isolated Toolbox-based Ansible controller with the required collections and a reproducible
+  project checkout; define its least-privilege SSH access, known-host handling, and Vault workflow without
+  storing secrets in the image or repository.
+- [ ] Define the explicit Uranus provisioning workflow from Cerberus, including inventory boundaries,
+  validation-only runs, and separate approval for any destructive cluster operation.
+- [ ] Design rootless Podman/Quadlet services for Grafana, Prometheus, and Loki, including persistent local
+  state, service ownership, LAN exposure/authentication, resource limits, updates, and backups.
+- [ ] Size and enforce a 30-day local hot-retention policy for metrics and logs on the 256 GB SSD; validate
+  actual disk growth and alert before capacity exhaustion.
+- [ ] Create and validate a dedicated Atlas NFS cold-storage dataset and least-privilege export for Cerberus;
+  do not use a broad existing share or couple it to unrelated Atlas application state.
+- [ ] Implement scheduled, idempotent exports of data older than 30 days to the Atlas NFS cold tier, with
+  locking, capacity checks, integrity verification, retention rules, failure monitoring, and a tested restore.
+- [ ] Validate management-plane recovery: rebuild Cerberus, restore observability history from Atlas, and
+  confirm that Uranus provisioning can resume without depending on unreproducible local state.
+
 ## Coding Agent Notes
 - Shared agent definitions and lifecycle flags live in `ai_agents` in `ansible/inventory/group_vars/all.yml`.
 - Shared agent dotfiles live in `ai_agents_dotfiles`; rendered configs live in `ai_agents_templates`.

README.it.md

@@ -95,6 +95,27 @@ Nota sullo stato attuale del playbook principale:
 - `ansible/site.yml` applica il profilo server Rocky a `prometheus` con DNF, systemd, dotfiles server e firewalld
 - `ansible/site.yml` applica il profilo NAS Rocky su `atlas` tramite SSH remoto
 
+## Nodo pianificato e posticipato: Cerberus
+
+`cerberus` e un nodo di management **posticipato**, in attesa dell'allestimento
+fisico dell'ufficio nella nuova casa. Non e ancora presente nell'inventory e non
+esistono ruoli o playbook che lo prendano come target.
+
+L'hardware previsto e un Lenovo ThinkCentre M700 Tiny (Intel Core i3-6100T,
+8 GB di RAM e SSD da 256 GB) con Ethernet nativa a 1 Gbps. Condividera monitor
+e periferiche di Ikaros tramite uno switch KVM a ingressi multipli, usando un
+cavo passivo DisplayPort-HDMI per il collegamento video. Il sistema operativo
+previsto e Fedora Sericea, la variante Fedora immutabile con compositor Wayland
+Sway.
+
+Cerberus sara un management plane isolato: Ansible verra eseguito in un ambiente
+Toolbox dedicato per il provisioning del futuro cluster `uranus`, anziche da
+Ikaros o da un host non gestito. Lo stack di osservabilita rootless Podman
+eseguira Grafana, Prometheus e Loki. L'SSD locale sara l'hot storage, con
+metriche e log conservati per 30 giorni; esportazioni programmate trasferiranno
+i dati storici piu vecchi su un dataset Atlas montato via NFS come cold storage.
+Il piano di implementazione, con prerequisiti espliciti, e in `AGENTS.md`.
+
 ## Desktop
 
 Target operativi:

README.md

@@ -67,6 +67,27 @@ The official ChatGPT desktop RPM is enabled only on `ikaros` and `nymph`. The
 playbook configures OpenAI's signed RPM repository and imports its pinned RPM
 signing key before installation; subsequent updates are handled by DNF.
 
+## Deferred planned node: Cerberus
+
+`cerberus` is a **postponed** management-plane node, pending the physical setup
+of the office in the new house. It is not yet an inventory host and no role or
+playbook targets it.
+
+The planned hardware is a Lenovo ThinkCentre M700 Tiny (Intel Core i3-6100T,
+8 GB RAM, and a 256 GB SSD) with native 1 Gbps Ethernet. It will share Ikaros'
+monitor and peripherals through a multi-input KVM switch, using a passive
+DisplayPort-to-HDMI cable for its video connection. Fedora Sericea, the
+immutable Fedora variant with the Sway Wayland compositor, is the intended
+operating system.
+
+Cerberus will be an isolated management plane: Ansible will run from a
+dedicated Toolbox environment to provision the future `uranus` cluster, rather
+than from Ikaros or an unmanaged host. Its rootless Podman observability stack
+will run Grafana, Prometheus, and Loki. The local SSD is the hot tier and
+retains metrics and logs for 30 days; scheduled exports will place older
+historical data on an NFS-mounted Atlas dataset as the cold tier. The detailed,
+implementation-gated plan is maintained in `AGENTS.md`.
+
 ## Desktop profiles
 
 - `ikaros`: stable Fedora Workstation + GNOME desktop.