SysV, SystemD and UpStArt
From Linuxintro
SysV is a framework for scheduling tasks to start at boot time. It is beeing successed by systemd and upstart. This affects how services are started and stopped. With systemd you start a service like
/etc/init.d/ntp start
With SystemD you do it with
systemctl start ntp
| what you want to do | how you do it with SysV | how you do it with SystemD |
|---|---|---|
| start service foo | /etc/init.d/foo start | systemctl start foo |
| stop service foo | /etc/init.d/foo stop | systemctl stop foo |
| find out if service foo is running | /etc/init.d/foo status | systemctl status foo |
| schedule service foo to start on boot | chkconfig foo on | chkconfig foo on |
| change "runlevel" to multi-user | init 2 | systemctl isolate multi-user.target |
SystemD
SystemD cannot only manage services, but also targets. Targets are sets of services. They differ from runlevels in that multiple of them can be active:
# systemctl list-units --type target | cat UNIT LOAD ACTIVE SUB JOB DESCRIPTION basic.target loaded active active Basic System cryptsetup.target loaded active active Encrypted Volumes getty.target loaded active active Login Prompts
