Systemd 101

[GreyGeek]

An excellent summary of systemd and systemctl:
https://wiki.sabayon.org/index.php?t...HOWTO:_systemd

[GreyGeek]

systemd-analyze blame > blame.txt
Creates a text file containing starting times and durations for units during the boot process

systemd-analyze plot > plot.svg
Outputs an svg graphic of blame that can be read by GIMP or GwenView.

jerry@jerry-Aspire-7739:~$ [B]systemd-analyze critical-chain[/B]
The time after the unit is active or started is printed after the "@" character.
The time the unit takes to start is printed after the "+" character.

graphical.target @31.583s
└─multi-user.target @31.583s
  └─aiccu.service @26.697s +4.885s
    └─network-online.target @26.350s
      └─NetworkManager-wait-online.service @16.513s +9.836s
        └─NetworkManager.service @13.598s +2.896s
          └─dbus.service @12.653s
            └─basic.target @12.649s
              └─sockets.target @12.649s
                └─snapd.socket @12.590s +51ms
                  └─sysinit.target @12.569s
                    └─apparmor.service @5.391s +7.123s
                      └─local-fs.target @5.390s
                        └─run-user-118.mount @24.505s
                          └─local-fs-pre.target @5.390s
                            └─systemd-remount-fs.service @5.261s +73ms
                              └─systemd-journald.socket @2.133s
                                └─-.mount @2.130s
                                  └─system.slice @2.132s
                                    └─-.slice @2.130s
jerry@jerry-Aspire-7739:~$

Reboot: systemctl reboot
Shutdown: systemctl poweroff

Others:

System Commands:
  is-system-running               Check whether system is fully running
  default                         Enter system default mode
  rescue                          Enter system rescue mode
  emergency                       Enter system emergency mode
  halt                            Shut down and halt the system
  poweroff                        Shut down and power-off the system
  reboot [ARG]                    Shut down and reboot the system
  kexec                           Shut down and reboot the system with kexec
  exit [EXIT_CODE]                Request user instance or container exit
  switch-root ROOT [INIT]         Change to a different root file system
  suspend                         Suspend the system
  hibernate                       Hibernate the system
  hybrid-sleep                    Hibernate and suspend the system

Systemd binaries:

/bin/systemd
/bin/systemd-ask-password
/bin/systemd-escape
/bin/systemd-hwdb
/bin/systemd-inhibit
/bin/systemd-machine-id-setup
/bin/systemd-notify
/bin/systemd-tmpfiles
/bin/systemd-tty-ask-password-agent
/usr/bin/systemd-analyze
/usr/bin/systemd-cat
/usr/bin/systemd-cgls
/usr/bin/systemd-cgtop
/usr/bin/systemd-delta
/usr/bin/systemd-detect-virt
/usr/bin/systemd-gnome-ask-password-agent
/usr/bin/systemd-manager
/usr/bin/systemd-manager-pkexec
/usr/bin/systemd-path
/usr/bin/systemd-resolve
/usr/bin/systemd-run
/usr/bin/systemd-stdio-bridge

Starting, stopping and reloading a unit:
systemctl {start, stop, restart, reload} some.service

Later: Using systemd to replace cron tasks, and the three states of a service: enabled, disabled and mask.

[GreyGeek]

YAST - Yet Another Systemd Tutorial