feat: add host_agent plugin — push-model host resource monitoring

Lightweight stdlib-only Python agent runs on each monitored host, collects CPU / memory / disk / load / uptime from /proc every 30s, and POSTs signed payloads to the Roundtable ingest endpoint. One-line curl-pipe installer creates a hardened systemd unit; admin UI manages host registrations with rotate / revoke. - agent.py: 370 LoC single-file daemon, ring buffer + exponential backoff - ingest route: bearer-token auth, metric expansion into plugin_metrics - install.sh.j2: systemd unit with NoNewPrivileges / ProtectSystem / ProtectHome - settings UI: add host / rotate token / delete registration (admin-only) - dashboard widgets: fleet-glance table + per-host history chart - stale-agent scheduler: 60s log warning for agents past 180s silence Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-04-15 01:04:51 -04:00
parent be4654fc72
commit 7468806bad
14 changed files with 1210 additions and 0 deletions
@@ -0,0 +1,81 @@
+#!/bin/sh
+# Roundtable host agent installer
+# Generated for: {{ host_name }}  ({{ host_address }})
+# Roundtable URL: {{ url }}
+set -e
+
+ROUNDTABLE_URL="{{ url }}"
+AGENT_TOKEN="{{ token }}"
+AGENT_VERSION="{{ agent_version }}"
+
+AGENT_USER="roundtable-agent"
+AGENT_DIR="/usr/local/lib/roundtable-agent"
+CONF_FILE="/etc/roundtable-agent.conf"
+UNIT_FILE="/etc/systemd/system/roundtable-agent.service"
+
+# ── preflight ────────────────────────────────────────────────────────────────
+[ "$(id -u)" = "0" ] || { echo "must run as root (use sudo)"; exit 1; }
+command -v systemctl >/dev/null 2>&1 || { echo "systemd not found — unsupported init system"; exit 1; }
+command -v python3   >/dev/null 2>&1 || { echo "python3 not found — install python3 first"; exit 1; }
+
+# Handle --uninstall
+if [ "${1:-}" = "--uninstall" ]; then
+    systemctl disable --now roundtable-agent.service 2>/dev/null || true
+    rm -f "$UNIT_FILE" "$CONF_FILE"
+    rm -rf "$AGENT_DIR"
+    systemctl daemon-reload
+    # keep the system user — removing it risks orphaned files elsewhere
+    echo "uninstalled"
+    exit 0
+fi
+
+# ── create system user ───────────────────────────────────────────────────────
+if ! id "$AGENT_USER" >/dev/null 2>&1; then
+    useradd --system --no-create-home --shell /usr/sbin/nologin "$AGENT_USER"
+fi
+
+# ── drop the agent file ──────────────────────────────────────────────────────
+mkdir -p "$AGENT_DIR"
+curl -sSL "${ROUNDTABLE_URL}/plugins/host_agent/agent.py" -o "$AGENT_DIR/agent.py"
+chmod 0755 "$AGENT_DIR/agent.py"
+chown root:root "$AGENT_DIR/agent.py"
+
+# ── write config ─────────────────────────────────────────────────────────────
+cat > "$CONF_FILE" <<EOF
+url = $ROUNDTABLE_URL
+token = $AGENT_TOKEN
+interval_seconds = 30
+EOF
+chown "root:$AGENT_USER" "$CONF_FILE"
+chmod 0640 "$CONF_FILE"
+
+# ── write systemd unit ───────────────────────────────────────────────────────
+cat > "$UNIT_FILE" <<EOF
+[Unit]
+Description=Roundtable host agent
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Type=simple
+User=$AGENT_USER
+ExecStart=/usr/bin/python3 $AGENT_DIR/agent.py
+Restart=on-failure
+RestartSec=10
+NoNewPrivileges=yes
+ProtectSystem=strict
+ProtectHome=yes
+PrivateTmp=yes
+ReadOnlyPaths=/proc /sys
+
+[Install]
+WantedBy=multi-user.target
+EOF
+
+systemctl daemon-reload
+systemctl enable --now roundtable-agent.service
+
+echo
+echo "Roundtable host agent $AGENT_VERSION installed and running."
+echo "Check status:  systemctl status roundtable-agent"
+echo "Logs:          journalctl -u roundtable-agent -f"