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保持 systemd 服务启动的进程处于活动状态时出现问题

tag-icon • tag-icon systemd services systemd-timer
保持 systemd 服务启动的进程处于活动状态时出现问题

我正在努力让我的第一项systemd服务按预期工作。这是我所拥有的：

gateway-watchdog.service：

# A systemd service for the Gateway Watchdog

[Unit]
Description=gateway-watchdog: Watchdog to ensure that Gateway (gateway.py) is running

[Service]
Type=simple
User=root
WorkingDirectory=/home/ubuntu/lora_gateway/
ExecStart=/home/ubuntu/lora_gateway/watchdog.sh

[Install]
WantedBy=multi-user.target

gateway-watchdog.timer：

[Unit]
Description=gateway-watchdog: Timer to run the associated gateway-watchdog service

[Timer]
# Run service 1 minute after boot
OnBootSec=1min
# Run service 15 minutes after the last run
OnUnitActiveSec=30s

[Install]
WantedBy=timers.target

watchdog.sh有这些行（包含在一些if语句中）：

#!/bin/bash
...
if [[condition]]; then
    command="python3 gateway.py"
        # Process needs to be run in the background with '&'. If it isn't, the systemd service will treat this script
        # as still running and so not re-run it at the time specified by the timer service.
    echo "2 $(date +'%F %T'): Running: $command" >> $LOG_FILE_PATH
    eval "$command"
        # Command must be run using eval. If it isn't, the ampersand at the end of the command is effectively ignored
    exit
fi

我需要的：

该服务将运行watchdog.sh。如果if脚本中的条件为真，watchdog.sh则将python3 gateway.py作为单独的进程启动，然后退出，并且该服务将不再被视为活动状态，因此它将在 30 秒后再次运行。

通过不同服务的各种组合Type（我已经尝试过simple、oneshot和forking），在和/或我的命令行&末尾使用，和/或使用，我可以启动并保持活动状态，或者让服务运行30 秒，但不能两者兼而有之。ExecStartnohupgateway.py

当python3 gateway.py保持活动状态时，它始终是服务的一部分CGroup，因此服务会保留active (running)。

我怎样才能改变这种行为以实现我想要做的事情？任何想法都将不胜感激。

编辑：我已经更新了上面的文件内容，以反映根据 U 的建议所做的更改。

根据上面给出的文件，sudo systemctl status gateway-watchdog.service给出：

● gateway-watchdog.service - gateway-watchdog: Watchdog to ensure that Gateway (gateway.py) is running
     Loaded: loaded (/etc/systemd/system/gateway-watchdog.service; enabled; vendor preset: enabled)
     Active: active (running) since Thu 2022-01-13 01:45:25 UTC; 8s ago
TriggeredBy: ● gateway-watchdog.timer
   Main PID: 30684 (watchdog.sh)
      Tasks: 3 (limit: 4435)
     CGroup: /system.slice/gateway-watchdog.service
             ├─30684 /bin/bash /home/ubuntu/lora_gateway/watchdog.sh
             └─30696 python3 gateway.py

Jan 13 01:45:25 ubuntu systemd[1]: Started gateway-watchdog: Watchdog to ensure that Gateway (gateway.py) is running.

好：gateway.py进程保持运行。错误：服务 30 秒后不会再次运行，因为之前的运行仍然处于活动状态。

如果我把&后面放入command="python3 gateway.py &"，sudo systemctl status gateway-watchdog.service给出：

● gateway-watchdog.service - gateway-watchdog: Watchdog to ensure that Gateway (gateway.py) is running
     Loaded: loaded (/etc/systemd/system/gateway-watchdog.service; enabled; vendor preset: enabled)
     Active: inactive (dead) since Thu 2022-01-13 01:49:05 UTC; 6s ago
TriggeredBy: ● gateway-watchdog.timer
    Process: 33724 ExecStart=/home/ubuntu/lora_gateway/watchdog.sh (code=exited, status=0/SUCCESS)
   Main PID: 33724 (code=exited, status=0/SUCCESS)

Jan 13 01:49:05 ubuntu systemd[1]: Started gateway-watchdog: Watchdog to ensure that Gateway (gateway.py) is running.
Jan 13 01:49:05 ubuntu systemd[1]: gateway-watchdog.service: Succeeded.

好：该服务处于非活动状态，因此 30 秒后它会再次运行。坏：python3 gateway.py进程立即终止。

答案1

我通过参考找到了解决方案https://stackoverflow.com/a/57041270/2909854。现在command的行是watchdog.sh：

command="systemd-run --scope -E setsid nohup python3 $GATEWAY_SCRIPT_PATH"

我还必须将我的服务Type集更改为forking，并添加TimeoutSec=1.不确定超时是否必要，但至少在调试时有帮助。

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