rc-local.service

flexmi@td1:~$ cd /lib/systemd/system/
flexmi@td1:/lib/systemd/system$ ls |grep rc-local.service
rc-local.service
rc-local.service.d
flexmi@td1:/lib/systemd/system$ pwd
/lib/systemd/system
flexmi@td1:/lib/systemd/system$

确保有rc-local.service文件，没有手动添加，内容如下：

#flexmi@td1:/lib/systemd/system$ cat ./rc-local.service

#  SPDX-License-Identifier: LGPL-2.1+
#
#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.

# This unit gets pulled automatically into multi-user.target by
# systemd-rc-local-generator if /etc/rc.local is executable.
[Unit]
Description=/etc/rc.local Compatibility
Documentation=man:systemd-rc-local-generator(8)
ConditionFileIsExecutable=/etc/rc.local
After=network.target

[Service]
Type=forking
ExecStart=/etc/rc.local start
TimeoutSec=0
RemainAfterExit=yes
GuessMainPID=no

rc.local

找到rc.local文件，没有就创建在/etc目录下，内容为你需要执行的脚本内容或者你需要执行的脚本启动命令

flexmi@td1:/lib/systemd/system$ cd /etc
flexmi@td1:/etc$ ls |grep rc.local
rc.local
flexmi@td1:/etc$ cat ./rc.local
#!/bin/bash
cd /home/flexmi/cmss
sudo ./start.sh
exit 0
flexmi@td1:/etc$

注意要给rc.local脚本文件添加执行权限

sudo chmod +x ./rc.local

启动服务

sudo systemctl enable rc-local

sudo systemctl start rc-local.service

sudo systemctl status rc-local.service

注意

1. 如果服务启动失败，看看是不是rc.local的问题，脚本的开头一定要是 #!/bin/bash
2. rc.local脚本的后面一定要加上exit 0

下面是我在操作过程中的截图：
启动失败：

启动成功