# Deployment Installs LLeMbas as a **system** service behind nginx with a self-signed certificate. Written for a systemd + nginx host; tested on Arch. | | Default | |---|---| | Service user | `lembas` (system account, `nologin`) | | Home | `/home/lembas` | | Install prefix | `/srv/lembas` (bind mount of the home) | | Checkout | `$PREFIX/app` | | Virtualenv | `$PREFIX/venv` | | Database | `$PREFIX/data/lembas.db` | | Environment | `$PREFIX/lembas.env` (mode 600) | | Unit | `/etc/systemd/system/lembas.service` | | Vhost | `/etc/nginx/conf.d/.conf` | | Listens on | `127.0.0.1:8080` — reachable only through nginx | The prefix defaults to a bind mount of the service user's home because on many machines the root filesystem is small while `/home` is not, and the virtualenv plus database belong on the larger volume. Set `PREFIX=$HOME_DIR` to skip it. ## First install ```bash SITE_HOST=chat.example ./deploy/install.sh ``` Idempotent — safe to re-run. It creates the user and bind mount, clones the repo, builds the venv, generates `lembas.env` with a fresh `LEMBAS_SECRET_KEY`, installs the unit and vhost, issues a self-signed certificate, adds a `/etc/hosts` entry if the name does not already resolve, and enables the service. Then open `https://`, accept the certificate warning, and create the first account — it becomes the administrator. Everything is overridable from the environment: | Variable | Default | | |---|---|---| | `SITE_HOST` | `lembas.local` | nginx `server_name` and certificate CN | | `APP_PORT` | `8080` | loopback port the service binds | | `SERVICE_USER` | `lembas` | system account to run as | | `HOME_DIR` | `/home/lembas` | that account's home | | `PREFIX` | `/srv/lembas` | install root (bind mount of `HOME_DIR`) | | `REPO_URL` | this checkout's `origin` | so a fork deploys itself. **Must be https** — see below | | `LEMBAS_BRANCH` | `main` | branch to fetch, and what the `edge` channel follows | | `LEMBAS_CHANNEL` | `stable` | `stable` follows release tags, `edge` follows the branch tip | | `INSTALL_UPDATE_HELPER` | `0` | `1` lets the web interface deploy that branch as root | **The deployment fetches over HTTPS, on purpose.** The service user has no SSH key and should not have one: a credential that can push to the repository, sitting on a box, to do a read-only job. If you push over SSH your checkout's `origin` is an `ssh://` URL, which is the one thing that cannot work here — so the installer refuses it and names the fix rather than letting the clone fail with `Permission denied (publickey)` from an account you were not thinking about. ## Channels | | follows | for | |---|---|---| | `stable` (default) | the newest `vX.Y.Z` tag | anybody running this | | `edge` | the tip of `LEMBAS_BRANCH` | whoever is building it | **A branch tip is not a release.** Following `main` means deploying whatever was pushed five minutes ago, possibly mid-feature — right for development and wrong for a machine somebody depends on. Stable is the default for that reason. A tag with a suffix (`v1.1.0-rc1`) is deliberately **not** a release: git's version sort puts it *above* `v1.1.0`, so accepting one would step a stable host onto a release candidate on the strength of a hyphen. A prerelease is something you check out by name. Release notes travel inside **annotated** tags, so `git tag -a v1.1.0 -m "…"` is what puts them on the update page. No forge API is involved anywhere — which matters more than it sounds: a token on the deployment host to answer a read-only question about version numbers is a bad trade, it would tie this to one forge, and the Gitea API this was checked against returns a 500 from a server-side panic on exactly that endpoint. ## Updating from the web interface `/admin/updates` says what is running (`git describe`, so `1.0.0` at a tag and `1.0.0-7-gd4f56d` seven commits past one), what the channel offers, the release notes, and the commits between. **Checking** reaches the remote; opening the page does not. The button is opt-in, and the reason is a boundary rather than caution: ```bash INSTALL_UPDATE_HELPER=1 SITE_HOST=chat.example ./deploy/install.sh ``` That installs `lembas-update.path` and `lembas-update.service`. The web interface writes `$PREFIX/data/update-requested`; the path unit notices and the service runs `update.sh` **as root**, on the configured channel. **What that grants.** Anybody who can administer this web interface can then deploy whatever is on the configured branch and restart the service. That is the point of it, and it is why it is not the default. **What it deliberately does not grant.** The request file carries nothing that reaches a command line — no ref, no branch, no channel, no arguments. Both are baked into the unit at install time, so the button is always "deploy the channel this host was configured with" and never "deploy something else". Re-running the installer without the flag removes both units and the marker, and the page goes back to printing the manual command. Without the helper the page says so and shows `sudo …/deploy/update.sh`, which is the same honest degradation the SSH and search extras have. ## Deploying a change ```bash git push ./deploy/update.sh ``` `update.sh` fetches, hard-resets the deployment checkout to `origin/main`, reinstalls dependencies and restarts, printing the commits it pulled. The hard reset is deliberate: nothing is ever edited in place there, so there is no local work to preserve and no conflicts to resolve. ## In a container A `Dockerfile` and a `docker-compose.yml` are in the repository root. ```bash echo "LEMBAS_SECRET_KEY=$(python -c 'import secrets;print(secrets.token_urlsafe(48))')" > .env docker compose up -d ``` It publishes on `127.0.0.1:8080` and expects **a TLS reverse proxy in front**. That is a constraint, not a preference: a service worker and a microphone both require HTTPS or localhost, so over plain http on a LAN address the app cannot be installed and cannot dictate — and the session cookie is deliberately not marked `secure`, so an attacker on that network could steal a session. Three things about the image: - **No secret key is baked in**, and compose refuses to start without one. A key in an image is a key every copy of that image shares, and rotating it signs everybody out *and* makes stored upstream API keys unreadable. - **`.git` is excluded**, so `/admin/updates` inside a container says it was not installed from a checkout and offers nothing. That is correct: a container is updated by pulling a new image. - **One replica.** The generation registry, the stop mechanism, the terminal sessions and the schedule ticker are all in-process — two would mean two tickers and every schedule firing twice. ## On Proxmox ```bash CTID=140 SITE_HOST=chat.example ./deploy/lxc-install.sh ``` Run on the Proxmox host. It creates an **unprivileged** Debian container, installs the dependencies, and runs `deploy/install.sh` inside it — the same installer, so a fix there reaches this without anybody remembering. Unprivileged is not a default to change: nothing LLeMbas does needs privilege, because agent chats run their commands over SSH on some *other* machine. ## Operating it ```bash systemctl status lembas journalctl -u lembas -f sudo -u lembas /srv/lembas/venv/bin/lembas info # paths and counts ``` Configuration lives in `$PREFIX/lembas.env`. Edit it and restart. ## Notes **The secret key is generated once.** `install.sh` will not overwrite an existing `lembas.env`. Rotating `LEMBAS_SECRET_KEY` signs every user out *and* makes stored upstream API keys unreadable — they would have to be re-entered. **nginx buffering is off for a reason.** Replies stream as server-sent events. With `proxy_buffering on` (the default) nginx holds the entire reply and delivers it in one lump at the end, which is indistinguishable from streaming being broken. `proxy_read_timeout` is raised to an hour because a model can think for minutes before the first token. **The vhost passes WebSocket upgrades through, and must.** The terminal panel is the one WebSocket in LLeMbas. A `location` that sets `Connection ""` — which is what SSE alone needs, and what this template used to say — fails every handshake, and a failed handshake tells the browser nothing: no status, no reason. The `map $http_upgrade` at the top of the vhost yields the empty string when the client did not ask to upgrade, so streaming is unaffected. `update.sh` warns when the installed vhost has drifted from the template, because this is the failure most likely to be diagnosed as a bug in the application. **Every restart kills every open shell.** A reply being written is persisted with whatever it has; a terminal has nothing to persist, so a command still running on the far side is cut off. `update.sh` restarts unconditionally, so a deploy in the middle of somebody's `apt-get dist-upgrade` ends it. The panel is told why rather than silently reconnecting to a new shell, which would have lost the working directory and the half-typed command. **A terminal is not in the transcript, and is not logged.** The open and the close are logged with the user, the chat and the connection; what was typed is not recorded anywhere. That follows from the design — the chat's mode governs the model, not the person at the keyboard — but everything else an agent chat does *is* in the transcript, so it is a difference in kind and worth knowing before somebody goes looking for the history. **Nothing an agent does runs on this machine.** Agent chats execute their commands over SSH, on a host somebody added and prepared — a container, a VM, another machine. That is the whole isolation story, and it is why the unit can stay locked down instead of being opened up to make room for a sandbox. `ProtectSystem=full` rather than `strict` only because the data directory must be writable and `strict` would mean listing every path. The practical consequence for whoever runs this: **the security of an agent chat is the security of the host behind its SSH profile.** A throwaway container with the one project mounted into it is a very different thing from a key to a production server, and LLeMbas cannot tell them apart. **Use a real certificate if this is exposed beyond a trusted LAN.** The self-signed cert exists so the install works with no external dependencies; point `ssl_certificate` at a real one and nothing else needs to change. The session cookie is deliberately not marked `secure`, so that a LAN install over plain http can sign anybody in at all. That has always meant a network attacker on http could steal a session; with the terminal it also means they could open an interactive shell on the machine behind that chat. If the terminal is switched on, run this over TLS. **One worker only.** True of generations already — the registry is in-process — and sharper here: with two workers a browser reconnecting to its terminal could land in the process that has no shell for it, and silently open a second one on the same machine.