Ubuntu shutdown stuck for 90 seconds? A Python asyncio service that won't honour SIGTERM, and how to fix it

Fri, 19 Jun 2026 10:58:00 +0800

TL;DR

After upgrading my home proxy box to Ubuntu 24.04, systemctl reboot stopped being fast: SSH would hang on for 90 seconds before the box actually shut down. journalctl made it obvious: smart-proxy.service: State 'stop-sigterm' timed out. Killing. — systemd sent SIGTERM, waited 90 seconds, nobody reacted, and SIGKILL was the only option left.

The root cause is not systemd’s fault and not Ubuntu’s fault. It is Python’s asyncio runtime not actually ending its child tasks when SIGTERM arrives — it is parked on a socket.recv and never voluntarily looks at the signal queue.

The fix has two halves, both required: (1) a systemd drop-in that lowers TimeoutStopSec from the default 90s down to 20s on the affected Python units; (2) inside the Python service itself, walk asyncio.all_tasks(), .cancel() the in-flight connection handlers on SIGTERM, and wrap self.stop() in asyncio.wait_for(..., timeout=10) as a safety net. After both halves, the same reboot drops from 90 seconds to one second.

Systemd on Margrop Blog

Ubuntu shutdown stuck for 90 seconds? A Python asyncio service that won't honour SIGTERM, and how to fix it