為什麼服務不能在啟動時啟動

我想用來systemd在啟動時啟動服務。但是我收到消息說該服務處於非活動狀態（已死）：

root@mdchost:/lib/systemd/system# systemctl status mdc_freespace_vldy_fusion_node.service
● mdc_freespace_vldy_fusion_node.service - MDC Freespace Vldy Fusion Node
  Loaded: loaded (/lib/systemd/system/mdc_freespace_vldy_fusion_node.service; enabled; vendor preset:
  Active: inactive (dead) since Sat 2018-08-04 01:06:48 BST; 5min ago
 Process: 3841 ExecStartPost=/bin/bash /usr/bin/mdc/base/set_limit.sh FUSI mdc_freespace_vldy_fusion_
 Process: 3838 ExecStart=/usr/bin/mdc/fusion/mdc_freespace_vldy_fusion_node (code=exited, status=0/SU
 Process: 3090 ExecStartPre=/opt/x86/ros/kinetic/bin/rosparam load /etc/mdc/fusion/kinematics_dynamic
 Process: 2266 ExecStartPre=/opt/x86/ros/kinetic/bin/rosparam load /etc/mdc/fusion/freespace_vldy_fus
Main PID: 3838 (code=exited, status=0/SUCCESS)

但我可以通過執行以下命令手動啟動它：

systemctl restart mdc_freespace_vldy_fusion_node.service

現在服務的狀態變為活動（執行）：

root@mdchost:/lib/systemd/system# systemctl status mdc_freespace_vldy_fusion_node.service
● mdc_freespace_vldy_fusion_node.service - MDC Freespace Vldy Fusion Node
  Loaded: loaded (/lib/systemd/system/mdc_freespace_vldy_fusion_node.service; enabled; vendor preset:
  Active: active (running) since Sat 2018-08-04 01:29:31 BST; 1s ago
 Process: 2065 ExecStartPost=/bin/bash /usr/bin/mdc/base/set_limit.sh FUSI mdc_freespace_vldy_fusion_
 Process: 2017 ExecStartPre=/opt/x86/ros/kinetic/bin/rosparam load /etc/mdc/fusion/kinematics_dynamic
 Process: 1991 ExecStartPre=/opt/x86/ros/kinetic/bin/rosparam load /etc/mdc/fusion/freespace_vldy_fus
Main PID: 2063 (mdc_freespace_v)
   Tasks: 6
  Memory: 3.5M
     CPU: 469ms
  CGroup: /system.slice/mdc_freespace_vldy_fusion_node.service
          └─2063 /usr/bin/mdc/fusion/mdc_freespace_vldy_fusion_node

這是我的服務文件：

[Unit]
Description=My Node
Requires=start_roscore.service
After=start_roscore.service

[Service]
User=mdc
Group=mdc

Type=simple
KillMode=proces
Restart=on-failure
RestartSec=16
StartLimitInterval=0

EnvironmentFile=/usr/bin/mdc/base/env.cfg
EnvironmentFile=/usr/bin/mdc/ros/ros.cfg

ExecStartPre=/opt/x86/ros/kinetic/bin/rosparam load /etc/mdc/fusion/freespace_vldy_fusion_config.yaml
ExecStartPre=/opt/x86/ros/kinetic/bin/rosparam load /etc/mdc/fusion/kinematics_dynamics.yaml

ExecStart=/usr/bin/mdc/fusion/mdc_freespace_vldy_fusion_node
ExecReload=/usr/bin/mdc/fusion/mdc_freespace_vldy_fusion_node

ExecStartPost=/bin/bash /usr/bin/mdc/base/set_limit.sh FUSI mdc_freespace_vldy_fusion_node

看看journalctl -u mdc_freespace_vldy_fusion_node.service。

此服務以 0 退出。關於早期啟動狀態，有些東西是/usr/bin/mdc/fusion/mdc_freespace_vldy_fusion_node不喜歡的。

引用自：https://unix.stackexchange.com/questions/484397