How to Ping Multiple Hosts in Parallel with Python ThreadPoolExecutor

A parallel host-pinging script using ThreadPoolExecutor and subprocess to check connectivity across multiple addresses concurrently.

Medium Python 3.9+ Aug 9, 2026 Automation & scripting 13 views 0 copies

thread-pool subprocess ping parallel network automation

Python code

34 lines
Python 3.9+
Run it 
import subprocess
from concurrent.futures import ThreadPoolExecutor
from pathlib import Path

HOSTS = [
    "google.com",
    "github.com",
    "stackoverflow.com",
    "nonexistent.invalid",
    "localhost",
]

def ping_host(host: str) -> str:
    """Ping a single host and return a status string."""
    result = subprocess.run(
        ["ping", "-c", "1", "-W", "1", host],
        capture_output=True,
        text=True,
        timeout=3,
    )
    if result.returncode == 0:
        return f"{host}: OK"
    return f"{host}: FAIL"

def ping_all(hosts: list[str], max_workers: int = 3) -> list[str]:
    """Ping all hosts in parallel using a thread pool."""
    with ThreadPoolExecutor(max_workers=max_workers) as executor:
        results = list(executor.map(ping_host, hosts))
    return results

if __name__ == "__main__":
    output = ping_all(HOSTS)
    for line in output:
        print(line)

Output

stdout 
google.com: OK
github.com: OK
stackoverflow.com: OK
nonexistent.invalid: FAIL
localhost: OK

How it works

The ThreadPoolExecutor creates a pool of worker threads that call ping_host concurrently, so multiple ping subprocesses run in parallel instead of sequentially. Each subprocess.run call captures stdout/stderr, so the script is quiet unless you print results. The -c 1 and -W 1 flags limit each ping to one packet and a one-second timeout, keeping the total runtime short. Using a with block ensures all worker threads and resources are cleaned up automatically. The list(executor.map(...)) preserves the input order, making results easy to pair with hostnames.

Common mistakes

  • Forgetting to set a subprocess timeout, so a slow host blocks the thread forever
  • Using shell=True without need, increasing security risks with host input
  • Passing a generator directly to executor.map and losing the ordered results
  • Assuming ping options work identically on Windows (use -n instead of -c)

Variations

  1. Use `subprocess.run` with `check=False` and handle return codes explicitly for custom error messages
  2. Switch to `asyncio.to_thread` or `asyncio.create_subprocess_exec` for async-friendly host checks

Real-world use cases

  • Monitoring site health from a dashboard by periodically pinging key endpoints across regions.
  • Pre-deployment connectivity checks that verify all services and infrastructure are reachable.
  • Network troubleshooting scripts that quickly identify which hosts are down during an incident.

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