SysVinit to Systemd Cheatsheet/zh

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该文档目的在于帮助系统管理员了解 systemd 中可以取代原先 sysvinit 工作流程的命令。如果想要了解 systemd 的一般信息，参阅 systemd。

注意 'service' 和 'chkconfig' 命令在 systemd 环境下依然可用，该教程目的在于告诉您如何使用原生 systemctl 替代品。

服务

sysvinit 命令	systemd 命令	备注
service frobozz start	systemctl start frobozz.service	用来启动一个服务 (并不会重启现有的)
service frobozz stop	systemctl stop frobozz.service	用来停止一个服务 (并不会重启现有的)。
service frobozz restart	systemctl restart frobozz.service	用来停止并启动一个服务。
service frobozz reload	systemctl reload frobozz.service	当支持时，重新装载配置文件而不中断等待操作。
service frobozz condrestart	systemctl condrestart frobozz.service	如果服务正在运行那么重启它。
service frobozz status	systemctl status frobozz.service	汇报服务是否正在运行。
ls /etc/rc.d/init.d/	ls /lib/systemd/system/*.service /etc/systemd/system/*.service	用来列出可以启动或停止的服务列表。
chkconfig frobozz on	systemctl enable frobozz.service	在下次启动时或满足其他触发条件时设置服务为启用
chkconfig frobozz off	systemctl disable frobozz.service	在下次启动时或满足其他触发条件时设置服务为禁用
chkconfig frobozz	systemctl is-enabled frobozz.service	用来检查一个服务在当前环境下被配置为启用还是禁用。
chkconfig frobozz --list	ls /etc/systemd/system/*.wants/frobozz.service	用来列出该服务在哪些运行级别下启用和禁用。
chkconfig frobozz --add		不需要，没有等效命令。

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, or service 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. Each target is named instead of numbered and is intended to serve a specific purpose. Some targets are implemented by inheriting all of the services of another target and adding additional services to it. There are systemd targets that mimic the common sysvinit runlevels so you can still switch targets using the familiar telinit 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 systemd target. 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 systemd target 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.