Initial commit: llama.cpp watchdog service

Monitors llama-server health with multi-phase checks (zombie detection,
health endpoint, loaded model probing) and auto-restarts via systemd or
manual relaunch on consecutive failures.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-02-06 22:47:12 -05:00
commit 321a43ac81
2 changed files with 234 additions and 0 deletions

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#!/usr/bin/env python3
"""
llama.cpp Watchdog Service
Monitors llama-server health and restarts on failure.
Detects:
- Router health endpoint failures
- Zombie child model-server processes
- Loaded models that are unreachable through the router
"""
import subprocess
import requests
import time
import signal
from datetime import datetime
# Configuration
SERVERS = [
{"name": "llama-main", "port": 11434, "service": "llama-cpp"},
{"name": "llama-alt", "port": 8082, "service": None},
]
LLAMA_SERVER_BIN = "/home/aj/llama.cpp/build/bin/llama-server"
MODELS_DIR = "/home/aj/models"
MODELS_PRESET = "/home/aj/models/models.ini"
CHECK_INTERVAL = 30 # seconds between health checks
HEALTH_TIMEOUT = 10 # seconds to wait for health response
DEEP_CHECK_TIMEOUT = 30 # seconds to wait for model probe
MAX_CONSECUTIVE_FAILURES = 2 # restart after this many failures
# Track failures per server
failure_counts = {}
def log(message):
"""Log with timestamp."""
print(f"[{datetime.now().strftime('%Y-%m-%d %H:%M:%S')}] {message}", flush=True)
def check_health(port):
"""Check if the router process is responding."""
try:
response = requests.get(f"http://localhost:{port}/health", timeout=HEALTH_TIMEOUT)
return response.status_code == 200
except requests.exceptions.RequestException:
return False
def get_loaded_models(port):
"""Get list of models the router reports as loaded."""
try:
response = requests.get(f"http://localhost:{port}/v1/models", timeout=HEALTH_TIMEOUT)
if response.status_code != 200:
return []
data = response.json()
return [
m["id"] for m in data.get("data", [])
if m.get("status", {}).get("value") == "loaded"
]
except Exception:
return []
def probe_model(port, model_name):
"""Send a minimal completions request to verify a loaded model actually works."""
try:
response = requests.post(
f"http://localhost:{port}/v1/chat/completions",
json={
"model": model_name,
"messages": [{"role": "user", "content": "hi"}],
"max_tokens": 1,
},
timeout=DEEP_CHECK_TIMEOUT,
)
return response.status_code == 200
except requests.exceptions.RequestException:
return False
def check_zombies():
"""Check for zombie llama-server processes."""
result = subprocess.run(["ps", "aux"], capture_output=True, text=True)
zombies = []
for line in result.stdout.split("\n"):
if "llama-server" in line and "<defunct>" in line:
parts = line.split()
if len(parts) >= 2:
zombies.append(parts[1])
return zombies
def restart_via_systemd(service_name):
"""Restart a server using systemd."""
log(f"Restarting {service_name} via systemd...")
result = subprocess.run(
["sudo", "systemctl", "restart", service_name],
capture_output=True,
text=True,
)
if result.returncode == 0:
log(f"{service_name} restart command succeeded")
else:
log(f"{service_name} restart failed: {result.stderr.strip()}")
# Give it time to come up
time.sleep(5)
def restart_manual(server):
"""Restart a server that has no systemd service by killing and re-launching."""
port = server["port"]
host = server["host"] if "host" in server else "0.0.0.0"
name = server["name"]
log(f"Restarting {name} (manual, port {port})...")
# Kill existing
subprocess.run(["pkill", "-9", "-f", f"llama-server.*--port.*{port}"], capture_output=True)
time.sleep(2)
cmd = [
LLAMA_SERVER_BIN,
"--host", host,
"--port", str(port),
"--models-dir", MODELS_DIR,
"--models-preset", MODELS_PRESET,
]
subprocess.Popen(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL, start_new_session=True)
time.sleep(5)
if check_health(port):
log(f"{name} started successfully")
else:
log(f"{name} failed to start")
def restart_server(server):
"""Restart a server using the appropriate method."""
service = server.get("service")
if service:
restart_via_systemd(service)
else:
restart_manual(server)
def run_watchdog():
"""Main watchdog loop."""
log("llama.cpp watchdog starting...")
for server in SERVERS:
failure_counts[server["port"]] = 0
while True:
try:
# --- Phase 1: Check for zombie child processes ---
zombies = check_zombies()
if zombies:
log(f"Found {len(zombies)} zombie llama-server process(es): {zombies}")
for server in SERVERS:
restart_server(server)
failure_counts[server["port"]] = 0
time.sleep(CHECK_INTERVAL)
continue
# --- Phase 2: Basic health checks ---
for server in SERVERS:
port = server["port"]
name = server["name"]
if not check_health(port):
failure_counts[port] += 1
log(f"{name} health check failed ({failure_counts[port]}/{MAX_CONSECUTIVE_FAILURES})")
if failure_counts[port] >= MAX_CONSECUTIVE_FAILURES:
restart_server(server)
failure_counts[port] = 0
continue
# --- Phase 3: Deep check - probe loaded models ---
loaded = get_loaded_models(port)
if loaded:
all_ok = True
for model in loaded:
if not probe_model(port, model):
log(f"{name}: loaded model '{model}' is unreachable!")
all_ok = False
break
if not all_ok:
failure_counts[port] += 1
log(f"{name} deep check failed ({failure_counts[port]}/{MAX_CONSECUTIVE_FAILURES})")
if failure_counts[port] >= MAX_CONSECUTIVE_FAILURES:
restart_server(server)
failure_counts[port] = 0
continue
# All checks passed
if failure_counts[port] > 0:
log(f"{name} recovered")
failure_counts[port] = 0
time.sleep(CHECK_INTERVAL)
except KeyboardInterrupt:
log("Watchdog stopping...")
break
except Exception as e:
log(f"Watchdog error: {e}")
time.sleep(CHECK_INTERVAL)
if __name__ == "__main__":
run_watchdog()

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[Unit]
Description=llama.cpp Watchdog Service
After=network.target
[Service]
Type=simple
User=aj
ExecStart=/usr/bin/python3 /home/aj/llamacpp-watchdog/llamacpp-watchdog.py
Restart=always
RestartSec=10
# Logging
StandardOutput=journal
StandardError=journal
SyslogIdentifier=llamacpp-watchdog
[Install]
WantedBy=multi-user.target