记录日常工作关于系统运维,虚拟化云计算,数据库,网络安全等各方面问题。
 
0

How to add a Custom Script to systemd in CentOS/RHEL 7
发表者：admin分类：Devops2020-07-10 18:01:17 阅读[872]

How to add a Custom Script to systemd in CentOS/RHEL 7

如何在CentOS / RHEL 7中将自定义脚本添加到systemd

The systemd facility replaces the older System-V initialization scripts from earlier releases. The systemd is an event-driven facility which allows non-dependent subsystems to be started, controlled, or stopped in parallel. Here we explain how to add a custom script to the systemd facility.

1. Write And Debug The Custom Script

Typically a systemd script is written as a shell script. Begin by writing your custom script using the normal conventions. We will call our script my-custom-script.sh and is straightforward:

#!/bin/sh
echo I am a custom script

2. The script must be executable

Lets make the script executable:

# chmod 0755 my-custom-script.sh

3. Describe The Custom Script To systemd

With the script written and tested manually, the script is ready to be described to the systemd system. To do this, a [name].service file is needed. The syntax uses the INI format commonly used for configuration files. Continuing our example, we need a my-custom-script.service file. The executable will run exactly once for each time the service is started. The service will not be started until the networking layer is up and stable:

# This is my-custom-script.service, which describes the my-custom-script.sh file
[Unit]
Description=This is executed on shutdown or reboot
DefaultDependencies=no
Wants=network-pre.target                                                                   # (if network is required before running the script)
Before=network-pre.target shutdown.target reboot.target halt.target                        # Defines the order in which units are stoped. #(REQUIRED)

[Service]
Type=oneshot                                                                               # enables specifying multiple custom commands that are then executed sequentially. (REQUIRED)
RemainAfterExit=true                                                                       # required by the oneshot setting (REQUIRED)
Environment=ONE='one' "TWO='2"                                                             # you can set some environment variables, that may be necessary to pass as arguments
ExecStart=/bin/true                                                                        # because is a shutdown script nothing is done when this service is started
ExecStop=/bin/bash /usr/local/bin/my-custom-script.sh ${ONE} ${TWO}                        # < --*********** change to the script full path ************ (REQUIRED)
TimeoutStopSec=1min 35s                                                                    # Configures the time to wait for stop.

[Install]
WantedBy=multi-user.target                                                                 # When this unit is enabled, the units listed in WantedBy gain a Want dependency on the unit. (REQUIRED)

4. Place The Service File Into The Expected Service Collection Directory

Lets place the custom script in service collection directory i.e. /etc/systemd/system/:

# cp my-custom-script.sh /etc/systemd/system/

5. Enable The Script For Future Reboots

Similar to the chkconfig from earlier versions, the service must be enabled. Since a new service was added, notify the systemd daemon to reconfigure itself:

# systemctl enable my-custom-script.service
# systemctl daemon-reload


转载请标明出处【How to add a Custom Script to systemd in CentOS/RHEL 7】。

《www.micoder.cc》 虚拟化云计算,系统运维,安全技术服务.

Tags： [阅读全文...]
网站已经关闭评论