wmantly
7e9a271090
JOIN KEYS v1.29.0 required an admin to pre-register every machine before its agent would be spoken to. The security model was right; the workflow was not -- installing the agent should be enough to add a host. POST /api/agent/join-keys mints one credential an operator hands out. A host presenting it is enrolled automatically and immediately issued its OWN per-agent token plus the public key it must pin, delivered in the config frame. The join key is a bootstrap credential, never the host's identity, so one key stays convenient without becoming a fleet-wide skeleton key: every host remains individually revocable. DIRECTORY Collapsing the tree did nothing. applyTreeCollapse found the caret with `.tree-caret i` and returned early when absent -- Font Awesome's SVG mode rewrites <i> to <svg>, so that selector matched nothing and the early return skipped setting hideBelowDepth. State now lives on the caret button and is rotated by CSS. The Discovery Plugins delete button called deleteDiscoveryPlugin(), which was never defined. The pane also had no .actionMessage, and confirmations render into one -- without it the promise never settles, so an awaited confirmation hangs forever and the action silently never happens. Plugin instances can now be edited. DISCOVERY A fresh install presented its own five containers as unmanaged discoveries. The Docker plugin now recognises the stack's compose project and attaches each container to the service it implements. Container slugs came from the container id, which changes on recreate, so every deploy minted a new resource and orphaned the old one. DOCS /docs/discovery 404'd (no slug entry) and `agents` pointed at plugins.md, leaving docs/agents.md unreachable. Adds docs/discovery.md. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
299 lines
14 KiB
Markdown
299 lines
14 KiB
Markdown
---
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layout: default
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title: Theta Agent & Endpoint Management
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nav_order: 5
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---
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# Theta Agent & Endpoint Management
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The **Theta Agent** (`theta-agent`) is a unified, 2-way Command & Control (C2) endpoint management daemon written in Go for Linux hosts across your home lab, infrastructure, or data center. It connects outbound via a long-lived WebSocket connection to the central **SSO Manager** (`wss://<sso-host>/api/agent/ws`), enabling real-time host telemetry, automated host discovery, and local-first administrative management.
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---
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## Enrollment
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An agent is only real if the SSO issued its credential. **Tokens the server did
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not issue are rejected** at the WebSocket handshake.
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There are two ways to get a host enrolled, and the first is the normal one.
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### Join key — install the agent and the host appears
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Hand the machine a **join key** and nothing else. On first connect the SSO
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enrolls the host, issues it its own per-agent token plus the public key it must
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pin, and the agent **writes both into its own `agent.yml`** and blanks the join
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key. From then on it authenticates as itself.
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```bash
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curl -fsSL https://<SSO_HOST>/resources/theta-agent/install.sh | sh -s -- \
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--url "https://<SSO_HOST>" --join-key "tjk_..."
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```
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That is the whole procedure — no pre-registering the machine, no copying a
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public key by hand. `setup.sh` mints a key and configures the stack's own host
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this way automatically.
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The join key is a *bootstrap* credential, not the host's identity. That
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distinction is what keeps one key convenient without making it a fleet-wide
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skeleton key: every host still ends up individually revocable, and a compromised
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host does not yield a credential that works anywhere else.
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| Endpoint | Purpose |
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| :--- | :--- |
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| `GET /api/agent/join-keys` | List keys (prefix + usage only; never the key) |
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| `POST /api/agent/join-keys` | Mint one — returned **once** |
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| `POST /api/agent/join-keys/:id/revoke` | Stop it enrolling new hosts |
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| `DELETE /api/agent/join-keys/:id` | Remove it |
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Revoking a join key does **not** disconnect hosts that already joined; they hold
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their own tokens by then. Revoke the agent itself to cut a specific host off.
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### Pre-registering a host
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When you want the agent bound to a specific Directory host up front, enroll it
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from **Directory → Install Agent**:
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1. Give the agent a name and **bind it to a host resource**. The binding is what
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links telemetry, status and commands to a Directory entry.
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2. Press **Enroll & issue token**. The SSO mints a 256-bit token, stores only its
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SHA-256, and shows the raw value **once**.
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3. Copy the generated install command — it already carries the token and the
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server's public key.
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A host that self-enrolls with a join key arrives unbound; bind it afterwards with
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`PUT /api/agent/nodes/:id` or from the Directory.
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Or via the API:
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```bash
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curl -X POST https://<SSO_HOST>/api/agent/enroll \
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-H "Authorization: Bearer <admin-api-token>" \
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-H 'Content-Type: application/json' \
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-d '{"name": "web01", "resourceId": "<host-resource-uuid>"}'
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```
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The response contains `token` (once only) and `publicKey`.
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| Endpoint | Purpose |
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| :--- | :--- |
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| `GET /api/agent/nodes` | Every enrolled agent, connected or not, plus the server public key |
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| `POST /api/agent/enroll` | Mint an agent + token |
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| `PUT /api/agent/nodes/:id` | Rename, or bind/unbind the host resource |
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| `POST /api/agent/nodes/:id/rotate` | Issue a new token; the old one stops working immediately |
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| `POST /api/agent/nodes/:id/revoke` | Disable the enrollment |
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| `DELETE /api/agent/nodes/:id` | Remove the enrollment |
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| `POST /api/agent/nodes/:id/command` | Send a command (signed automatically when high-risk) |
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Revoke, rotate and delete **drop any live connection immediately** — they do not
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wait for the agent to reconnect. Commands are addressed by agent **id**, never by
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token: a token is a credential and has no business in a URL or a log.
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Enrollment, revocation, rotation, every command, and every rejected connection
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are written to the application log as structured `"component":"agent"` records
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with the acting user.
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> **Lost the token?** It cannot be recovered — only its hash is stored. Rotate
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> the agent to issue a new one.
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---
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## Core Functionality
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### 1. Host Discovery & Inventory
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Upon establishing a WebSocket connection, the agent immediately pushes a comprehensive discovery payload:
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- **Hostname & Network Interfaces**: Hostname and all non-loopback IPv4 addresses and MACs.
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- **Operating System & Kernel**: Linux distribution, platform, and kernel version.
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- **Hardware Specs**: CPU model, total RAM (GB), and total root disk capacity (GB).
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- **Physical Location**: Location identifier string (e.g. `dc-01-rack-12`) configured in `agent.yml`.
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If the agent detects a network IP change, it automatically re-pushes an updated discovery payload to the SSO Manager.
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### 2. Real-Time Telemetry Streaming
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Every 30 seconds, the agent streams real-time performance metrics:
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- **CPU Load**: System-wide CPU utilization percentage.
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- **Memory Utilization**: RAM usage percentage and available memory.
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- **Disk Utilization**: Root filesystem usage percentage.
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- **ZFS Storage Health**: Health status of ZFS pools (e.g., `ONLINE`).
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- **NVIDIA GPU Load**: GPU compute utilization percentage (via `nvidia-smi`).
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---
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## Viewing in the SSO Manager
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Agent status and telemetry live on the **Directory** page — there is no separate
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Agents page. For each **host** resource that has a connected theta-agent, the
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Directory shows a status dot in the row:
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| Color | Meaning |
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| :--- | :--- |
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| **Green** | Connected, healthy (CPU/RAM/disk within limits). |
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| **Yellow** | Connected but under high load (CPU > 80% or RAM > 80% or disk > 90%). |
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| **Red** | **Enrolled but not connected.** The agent exists and is expected — this is a fault. |
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| **Grey** | No agent enrolled for this host, the enrollment is revoked, or the agent service is unreachable. |
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Red and grey used to be the same colour, which made an ordinary directory of
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hosts look like an outage. Because the enrollment now outlives the connection,
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"installed but down" is distinguishable from "never had an agent".
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Opening a host's resource modal reveals a **Metrics** tab with the agent's live
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telemetry (CPU/RAM/disk/ZFS/GPU) and discovery info (OS, kernel, IPs, location).
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An agent attaches to its host by its **enrollment binding** (`resourceId`), set
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when you enroll it or later via `PUT /api/agent/nodes/:id`. Agents enrolled
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without a binding fall back to matching their reported hostname against the
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resource name — the old behaviour, kept only as a fallback, because it silently
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failed whenever a Directory name differed from the machine's hostname and
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aliased two hosts that happened to share one.
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### Agent discovery feeds the Directory
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A bound agent's discovery payload is written onto its host resource (`os`,
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`kernel`, `cpu`, `ram_total_gb`, `disk_total_gb`, `ip`), tagged with
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`discovery_sources: ["theta-agent"]` and an `agentId` back-reference. An agent
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runs *on* the host it describes, so it is the most authoritative source the
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directory has. An unbound agent goes through the normal discovery reconciler
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instead, matching like any other source.
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---
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## Local-First Security & Capability Matrix
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To protect hosts against unauthorized control, `theta-agent` enforces a **strict, local-first capability matrix** defined in `/etc/theta42/agent.yml`. Central SSO Manager requests are checked against local configuration before execution; permissions cannot be overridden remotely.
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| Capability | Config Key | Risk Level | Description & Impact |
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| :--- | :--- | :--- | :--- |
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| **Telemetry** | `telemetry` | Safe | Streams read-only system metrics (CPU, RAM, Disk, ZFS, GPU). |
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| **Configure LDAP** | `configure_ldap` | Moderate | Writes updated SSSD configuration to `/etc/sssd/sssd.conf` & restarts `sssd`. |
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| **Service Control** | `service_control` | High | Restarts systemd services listed in an explicit allowlist (e.g., `["nginx", "docker", "sssd"]`). |
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| **Reboot** | `reboot` | High | Triggers an immediate system reboot (`systemctl reboot`). |
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| **Arbitrary Bash** | `arbitrary_bash` | Critical | Executes raw bash scripts sent from the SSO Manager as `root` (used for automated GitOps). |
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---
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## High-Risk Command Verification (Protocol v1.2.0)
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High-risk management commands (`reboot`, `service_restart`, `configure_ldap`, `arbitrary_bash`, `update_binary`) are cryptographically verified using **Ed25519 signatures**:
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1. The SSO Manager canonicalizes the command payload (sorted keys, no whitespace,
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no HTML escaping, `signature` omitted).
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2. The payload is signed with the SSO Manager's Ed25519 private key.
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3. The Base64 signature is appended to the message payload.
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4. The agent verifies the signature against the configured `public_key` in `/etc/theta42/agent.yml` before executing the action.
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**The signing key is persistent.** It lives in OpenBao at
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`secret/agent/signing-key` and survives restarts, so the `public_key` you pin in
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`agent.yml` keeps matching. (It used to be generated in memory at boot and
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changed on every restart, which made pinning impossible.) If the SSO cannot load
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or store a key it **refuses** to send high-risk commands rather than signing with
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one no agent has seen — `GET /api/agent/nodes` reports this as
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`signingAvailable: false`.
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This requires the `sso-broker` OpenBao policy to grant `secret/agent/*`. Re-run
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`./setup.sh` from theta-suite if you are upgrading.
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**Verification is fail-closed on the agent.** An agent with no `public_key`
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configured rejects every high-risk command. Earlier versions logged "skipping
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signature verification" and executed them, so an agent installed without a key
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would run `reboot`, `configure_ldap` and `arbitrary_bash` unverified.
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---
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## Installation & Deployment
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### Quick One-Liner Install
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Run the following command as `root` on the target Linux host:
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```bash
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curl -fsSL https://<SSO_HOST>/resources/theta-agent/install.sh | sh -s -- \
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--url "https://<SSO_HOST>" --token "<ISSUED_TOKEN>" --public-key "<BASE64_PUBLIC_KEY>"
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```
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Both values come from enrollment. The **Install Agent** modal builds this line
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for you with them already filled in. Omitting `--public-key` leaves the agent
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able to report telemetry but unable to accept any high-risk command.
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### Custom Config Wizard
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You can generate a Base64-encoded custom configuration using the **Install Agent** button on the **Directory Management** page in the SSO Manager UI:
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```bash
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curl -fsSL https://<SSO_HOST>/resources/theta-agent/install.sh | sh -s -- "<BASE64_ENCODED_CONFIG>"
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```
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---
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## Configuration File Example (`/etc/theta42/agent.yml`)
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```yaml
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# /etc/theta42/agent.yml
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server_url: "wss://sso.example.com"
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# Issued by the SSO. Left empty when installing with a join key -- the agent
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# fills it in itself once the server enrolls it.
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auth_token: "c8181ce0e55bf7302b11d719a7ae39adcd7604de461e6e363f8bb4fadf126acb"
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# Bootstrap credential. Used only while auth_token is empty, and blanked by the
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# agent once it has its own token.
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join_key: ""
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location: "dc-01-rack-12"
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# Base64 of the RAW 32-byte Ed25519 public key -- exactly the `publicKey` value
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# from enrollment or GET /api/agent/nodes. Not a PEM body: a base64-decoded
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# SPKI blob is 44 bytes, the agent requires 32, and it will refuse every signed
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# command if this is wrong.
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public_key: "D0cJB3iuStTzhXlu7tFDh/eEXFxRZwkuwQJJhFSqwlQ="
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capabilities:
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telemetry: true
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configure_ldap: true
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reboot: false
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service_control: ["nginx", "docker", "sssd"]
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arbitrary_bash: false
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```
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---
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## Troubleshooting: agent is rejected (`close 4001`)
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If the agent logs that the server rejected its token, the enrollment — not the
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network — is the problem. The SSO accepts the WebSocket upgrade and then closes
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with an application code:
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| Code | Meaning | Fix |
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| :--- | :--- | :--- |
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| `4001` | Token unknown, or never issued by this server | Enroll the host and put the issued token in `agent.yml` |
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| `4002` | Superseded — another connection authenticated as this agent | Normal; two copies of the agent are running |
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| `4003` | Enrollment revoked or deleted | Re-enroll |
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| `4004` | Token rotated; `agent.yml` has the old value | Copy the new token |
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The agent backs off for 5 minutes on `4001`/`4003`/`4004` rather than retrying
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every 5 seconds — a credential that is wrong will not fix itself, and hammering
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the SSO only floods its audit log.
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An agent installed before protocol v1.2.0 carries a token generated in the
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browser that the server never recorded, so it will be rejected with `4001` until
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re-enrolled. The quickest fix is to put a **join key** in its `agent.yml` as
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`join_key` and blank `auth_token` — it will re-enroll itself on the next
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reconnect.
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---
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## Troubleshooting: agent can't connect (`dial tcp ... i/o timeout`)
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If the agent host logs `Dial error: dial tcp <ip>:443: i/o timeout` while
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connecting to `wss://<sso-host>/api/agent/ws`, the WebSocket path is usually
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fine — this is a **network/NAT** problem, not an agent or SSO bug. A host behind
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the same NAT that owns the SSO often cannot reach its own **public IP** (no
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hairpin/loopback NAT on many home routers), so the TCP dial times out even
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though the same address works from outside.
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Fix options:
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1. Point `agent.yml` `server_url` at an address the host can reach directly —
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e.g. the SSO host's LAN IP (`http://<lan-ip>` or `http://<lan-ip>:3001` for a
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no-TLS direct path).
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2. Enable **NAT reflection / hairpin NAT** on the router so LAN hosts can reach
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their own public IP:443.
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3. Add a local route/firewall rule on the agent host for its public IP.
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> Note: on a deployment where the theta42 proxy fronts `sso.suite.example`, make
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> sure the proxy has a **persistent Host record** for the real SSO domain — not
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> just the `localtest.me` placeholder — so routing survives a proxy restart
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> (an in-memory lookup cache can mask a missing Redis record for up to ~1h).
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