SysVinit to Systemd Cheatsheet Linux服务配置

本文主要是介绍SysVinit to Systemd Cheatsheet Linux服务配置，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

1. fedora 15 开始使用systemd代替原来的sysv init了，对比下systemd下systemctl和原来的service，chkconfig。

http://fedoraproject.org/wiki/SysVinit_to_Systemd_Cheatsheet

还有一篇简单介绍systemd，和简单命令的使用的文章：http://fedoraproject.org/wiki/Systemd#Why_systemd.3F

2. Ubuntu下用sysv-rc-conf配置服务，可以用命令，也有ncurse的界面，配置方便；

SysVinit to Systemd Cheatsheet

This is a document to help system administrators who need to understand what commands in systemd replace their old workflow in sysvinit. If you want general information on systemd, refer tosystemd.

Note that the 'service' and 'chkconfig' commands will mostly continue to work as expected in the systemd world, this guide is how to use the native systemctl replacements.

Services

sysvinit Command	systemd Command	Notes
service frobozz start	systemctl start frobozz.service	Used to start a service (not reboot persistent)
service frobozz stop	systemctl stop frobozz.service	Used to stop a service (not reboot persistent)
service frobozz restart	systemctl restart frobozz.service	Used to stop and then start a service
service frobozz reload	systemctl reload frobozz.service	When supported, reloads the config file without interrupting pending operations.
service frobozz condrestart	systemctl condrestart frobozz.service	Restarts if the service is already running.
service frobozz status	systemctl status frobozz.service	Tells whether a service is currently running.
ls /etc/rc.d/init.d/	ls /lib/systemd/system/.service /etc/systemd/system/.service systemctl list-units --all	Used to list the services that can be started or stopped Used to list all the services and other units
chkconfig frobozz on	systemctl enable frobozz.service	Turn the service on, for start at next boot, or other trigger.
chkconfig frobozz off	systemctl disable frobozz.service	Turn the service off for the next reboot, or any other trigger.
chkconfig frobozz	systemctl is-enabled frobozz.service	Used to check whether a service is configured to start or not in the current environment.
chkconfig frobozz --list	ls /etc/systemd/system/*.wants/frobozz.service	Used to list what levels this service is configured on or off
chkconfig frobozz --add	systemctl daemon-reload	Used when you create a new service file or modify any configuration

Note that all /sbin/service and /sbin/chkconfig lines listed above continue to work on systemd, and will be translated to native equivalents as necessary. The only exception is chkconfig --list.

Additional commands
In SysVinit, services can define arbitrary commands. Examples would be service iptables panic, orservice httpd graceful. Native systemd services do not have this ability.

Any service that defines an additional command in this way would need to define some other, service-specific, way to accomplish this task when writing a native systemd service definition.

Check the package-specific release notes for any services that may have done this.

Runlevels/targets

Systemd has a concept of targets which serve a similar purpose as runlevels but act a little different. Eachtarget is named instead of numbered and is intended to serve a specific purpose. Sometargets are implemented by inheriting all of the services of another target and adding additional services to it. There are systemdtargets that mimic the common sysvinit runlevels so you can still switchtargets using the familiartelinit RUNLEVEL command. The runlevels that are assigned a specific purpose on vanilla Fedora installs; 0, 1, 3, 5, and 6; have a 1:1 mapping with a specific systemdtarget. Unfortunately, there's no good way to do the same for the user-defined runlevels like 2 and 4. If you make use of those it is suggested that you make a new named systemdtarget as/etc/systemd/system/$YOURTARGET that takes one of the existing runlevels as a base (you can look at/lib/systemd/system/graphical.target as an example), make a directory/etc/systemd/system/$YOURTARGET.wants, and then symlink the additional services that you want to enable into that directory. (The service unit files that you symlink live in/lib/systemd/system).

sysvinit Runlevel	systemd Target	Notes
0	runlevel0.target, poweroff.target	Halt the system.
1, s, single	runlevel1.target, rescue.target	Single user mode.
2, 4	runlevel2.target, runlevel4.target, multi-user.target	User-defined/Site-specific runlevels. By default, identical to 3.
3	runlevel3.target, multi-user.target	Multi-user, non-graphical. Users can usually login via multiple consoles or via the network.
5	runlevel5.target, graphical.target	Multi-user, graphical. Usually has all the services of runlevel 3 plus a graphical login.
6	runlevel6.target, reboot.target	Reboot
emergency	emergency.target	Emergency shell

Changing runlevels:

sysvinit Command	systemd Command	Notes
telinit 3	systemctl isolate multi-user.target (OR systemctl isolate runlevel3.target OR telinit 3)	Change to multi-user run level.
sed s/^id:.*:initdefault:/id:3:initdefault:/	ln -sf /lib/systemd/system/multi-user.target /etc/systemd/system/default.target	Set to use multi-user runlevel on next reboot.