When I "stop" a system process, the "ExecStart" command process does not stop

Newskooler

11/2/22, 1:48 PM

I run a system service with the following config my_script.service:

[Unit]
Description=My demo program.

[Service]
User=myname
ExecStart=/my_scripts/some_async_python_script.py
Restart=always
RestartSec=5s

[Install]
WantedBy=multi-user.target

Before running I would do this once: sudo systemctl daemon-reload and sudo systemctl enable my_script.service and then I would start like so: sudo systemctl start my_script.service

So far this work well.

The problem I have is that when I stop it with sudo systemctl stop my_script.service and then do htop I can see /my_scripts/some_async_python_script.py still running. I can see it has a parent process. When I kill the child process, it's dead (i.e. I don't need to kill the parent process).

My question is: Why is my service command still running even though I have stopped the service?

0 + 5

linux

service

systemd

Michael Hampton

11/2/22, 4:22 PM

What is unusual and unexpected about this Python script? e.g. does it fork? How did it get a child process anyway?

Newskooler

11/2/22, 4:46 PM

The python script connects to a websocket and stream data asynchronously and I suspect that's where the issue is (but don't understand fully why). The script uses libraries such as `from aiostream import stream` and `import socket` and `from websockets import connect` Does that info help at all?

Newskooler

11/13/22, 9:54 AM

@MichaelHampton is there any more info on my end I can help with?

Michael Hampton

11/13/22, 9:56 AM

What is the status of the service after you tried to stop it? What was in the journal?

Newskooler

11/13/22, 10:02 AM

Before I `stop` it says `Active: active (running)` and after `stop` it says `Active: inactive (dead)` (as expected). The Main PID is indeed gone (when I do `htop`, I don't see it anywhere), however I do see another PID running which is the code inside my systemd service. That one I need to stop manually. I don't know why systemd does not stop it as well.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: When I "stop" a system process, the "ExecStart" command process does not stop

TH: เมื่อฉัน "หยุด" กระบวนการของระบบ กระบวนการคำสั่ง "ExecStart" จะไม่หยุด

RO: Când „opresc” un proces de sistem, procesul de comandă „ExecStart” nu se oprește

RU: Когда я «останавливаю» системный процесс, процесс команды «ExecStart» не останавливается

VI: Khi tôi "dừng" một quy trình hệ thống, quy trình lệnh "ExecStart" không dừng

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