Ubuntu/Debian 解决 /etc/rc.local 开机启动问题

由于某些软件并没有增加开启启动的服务，很多时候需要手工添加，一般我们都是推荐添加命令到 /etc/rc.local 文件，但是 Ubuntu 默认不带 /etc/rc.local 文件，而 rc.local 服务却还是自带的

很多时候有些程序或者脚本都需要添加开机自启，最简单的方法就是使用rc.local自启，不过由于系统版本更替，很多新版本系统都没有rc.local文件了，比如Debian 9、Ubuntu 17.10、Ubuntu 18.04。这时候就需要我们手动设置下。

root@ubuntu ~ # cat /etc/systemd/system/rc-local.service
    # cat /lib/systemd/system/rc.local.service
    #  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
    ConditionFileIsExecutable=/etc/rc.local
    After=network.target
    
    [Service]
    Type=forking
    ExecStart=/etc/rc.local start
    TimeoutSec=0
    RemainAfterExit=yes
    GuessMainPID=no

并且默认情况下这个服务还是关闭的状态
    root@ubuntu ~ # systemctl status rc-local
    ● rc-local.service - /etc/rc.local Compatibility
       Loaded: loaded (/lib/systemd/system/rc-local.service; static; vendor preset: enabled)
      Drop-In: /lib/systemd/system/rc-local.service.d
               └─debian.conf
       Active: inactive (dead)

1、添加rc-local.service
--------------------

#以下为一整条命令，一起复制运行
    cat > /etc/systemd/system/rc-local.service <<EOF
    [Unit]
    Description=/etc/rc.local
    ConditionPathExists=/etc/rc.local
     
    [Service]
    Type=forking
    ExecStart=/etc/rc.local start
    TimeoutSec=0
    StandardOutput=tty
    RemainAfterExit=yes
    SysVStartPriority=99
     
    [Install]
    WantedBy=multi-user.target
    EOF

2、添加一个 /etc/rc.local 文件
-----------------------

#以下为一整条命令，一起复制运行
    cat <<EOF >/etc/rc.local
    #!/bin/sh -e
    #
    # rc.local
    #
    # This script is executed at the end of each multiuser runlevel.
    # Make sure that the script will "exit 0" on success or any other
    # value on error.
    #
    # In order to enable or disable this script just change the execution
    # bits.
    #
    # By default this script does nothing.
    
    exit 0
    EOF

3、添加权限并设置开机自启
-------------

chmod +x /etc/rc.local
    systemctl enable rc-local
    systemctl start rc-local.service

检查状态：
systemctl status rc-local.service

返回Active:active信息，则成功。

再次查看状态

root@ubuntu ~ # systemctl status rc-local
    ● rc-local.service - /etc/rc.local Compatibility
       Loaded: loaded (/lib/systemd/system/rc-local.service; static; vendor preset: enabled)
      Drop-In: /lib/systemd/system/rc-local.service.d
               └─debian.conf
       Active: active (exited) since Thu 2017-08-03 09:41:18 UTC; 14s ago
      Process: 20901 ExecStart=/etc/rc.local start (code=exited, status=0/SUCCESS)
    
    Aug 03 09:41:18 xtom-hk systemd[1]: Starting /etc/rc.local Compatibility...
    Aug 03 09:41:18 xtom-hk systemd[1]: Started /etc/rc.local Compatibility.

然后你就可以把需要开机启动的命令添加到 /etc/rc.local 文件，丢在 exit 0 前面即可，并尝试重启以后试试是否生效了

Last modification：May 30, 2020