无法让服务noip2在启动时启动

Question

我已经安装了非ip动态ddns，下面是指南：https://www.noip.com/support/knowledgebase/installing-the-linux-dynamic-update-client/。

我让服务通过了

sudo /usr/local/bin/noip2

但是，我希望服务在引导时启动，我尝试在/etc/init.d/noip2.sh中添加以下脚本

#######################################################
#! /bin/sh
# . /etc/rc.d/init.d/functions  # uncomment/modify for your killproc
case "$1" in
    start)
    echo "Starting noip2."
    /usr/local/bin/noip2
    ;;
    stop)
    echo -n "Shutting down noip2."
    killproc -TERM /usr/local/bin/noip2
    ;;
    *)
    echo "Usage: $0 {start|stop}"
    exit 1
esac
exit 0
#######################################################

其次是：

sudo chmod +x /etc/init.d/noip2.sh
sudo update-rc.d noip2.sh defaults

现在我应该可以从

sudo service noip2 start

但我不是。当我运行journalctl -xe时，我得到以下信息：

-- Unit noip2.service has begun starting up.
Nov 03 12:36:11 media systemd[3111]: noip2.service: Failed to execute command: Exec format error
Nov 03 12:36:11 media systemd[3111]: noip2.service: Failed at step EXEC spawning /etc/init.d/noip2.sh: Exec format error
-- Subject: Process /etc/init.d/noip2.sh could not be executed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- The process /etc/init.d/noip2.sh could not be executed and failed.
--
-- The error number returned by this process is 8.
Nov 03 12:36:11 media systemd[1]: noip2.service: Control process exited, code=exited status=203
Nov 03 12:36:11 media systemd[1]: noip2.service: Failed with result 'exit-code'.
Nov 03 12:36:11 media systemd[1]: Failed to start noip2.service.
-- Subject: Unit noip2.service has failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support

为用户PerDuck更新的信息:我得到以下错误尝试您的解决方案.*(试图添加

RestartSec=30

至少它现在一直在尝试，但它仍然没有开始。我仍然可以从sudo /usr/local/bin/noip2开始

错误：

Nov 03 23:26:42 media systemd[1]: noip2.service: Service hold-off time over, scheduling restart.
Nov 03 23:26:42 media systemd[1]: noip2.service: Scheduled restart job, restart counter is at 5.
Nov 03 23:26:42 media systemd[1]: Stopped noip2 service.
Nov 03 23:26:42 media systemd[1]: noip2.service: Start request repeated too quickly.
Nov 03 23:26:42 media systemd[1]: noip2.service: Failed with result 'start-limit-hit'.
Nov 03 23:26:42 media systemd[1]: Failed to start noip2 service.

Answer 1

自从Ubuntu15.04以来，控制后台进程(还有更多的)的标准方法是systemd。我建议从init.d脚本切换到systemd单元：

创建具有以下内容的文件/etc/systemd/system/noip2.service (并删除init.d脚本)：

[Unit]
Description=noip2 service

[Service]
Type=forking
ExecStart=/usr/local/bin/noip2
Restart=always

[Install]
WantedBy=default.target

然后发布

sudo systemctl daemon-reload

要使systemd知道新的单元(systemd缓存单元文件，此命令使systemd重新考虑其缓存)。

现在，您可以尝试启动和停止您的单元并查看其状态：

sudo systemctl status noip2
sudo systemctl start  noip2
sudo systemctl status noip2
sudo systemctl stop   noip2
sudo systemctl status noip2

要在启动时启动该单元，需要启用它：

sudo systemctl enable noip2

若要在启动时禁用自动启动，必须禁用该单元：

sudo systemctl disable noip2

大多数情况下，五个命令足以控制一个单位的行为：

systemctl start   $unit   # starts a unit NOW
systemctl stop    $unit   # stops a unit NOW
systemctl status  $unit   # shows status
systemctl enable  $unit   # starts a unit at boot time (but not NOW)
systemctl disable $unit   # stops autostart (but doesn't stop the unit NOW)

您还可以启用“自动启动”并立即启动该单元，或者禁用“自动启动”并立即停止：

systemctl enable  --now $unit   # enable and start in one go
systemctl disable --now $unit   # disable and stop in one go

更新

一些研究显示，noip2作为守护进程运行，即启动它时，它会创建另一个在后台运行的进程(所谓的分叉)，前台进程将立即返回(退出)。这就是init.d脚本和systemd单元失败的原因:他们启动noip2只是为了看到它立即退出。因此，systemd试图一次又一次地重新启动它，但没有结果。(默认情况下，systemd在放弃进程并使其处于失败状态之前，最多在10秒内重新启动进程5次。)

要告诉系统，该单元是分叉式的，添加行

Type=forking

到[Service]部分，正如我刚才在上面的片段中所做的那样。这告诉systemd预期主进程会立即返回，但会看到noip2生成(分叉)的进程。