LPIC 1 init, upstart, systemd

.service

Files ending in ________ represent a service unit

.target

Files ending in ________ represent a target that our system enters (similar to runlevels)

true

True of false, the service command works for backwards compatibility under systemd, but it is a link to /bin/systemctl

true

True or false, the location of the shutdown command under systemd systems is actually a sym link to /bin/systemctl

unit

a systemd configuration file that encodes information about a service, socket, device, mount point, swap file or partition, etc.

SysVinit startup scripts

bash scripts

.conf

file extension for SysVinit and upstart jobs

/etc/systemd/system/default.target

file used to enter into the default.target

telinit 3

in older Linux systems, runlevel command to change to multiuser mode with networking, starts the system normally

telinit 2

in older Linux systems, runlevel command to change to multiuser mode, does not configure network interfaces and does not export networks services

telinit 1

in older Linux systems, runlevel command to change to single-user mode, mode for administrative tasks

telinit 0

in older Linux systems, runlevel command to halt, shut down the system

telinit 6

in older Linux systems, runlevel command to reboot

telinit 5

in older Linux systems, runlevel command to start the system normally with appropriate display (GUI), same as runlevel 3 + display manager

telinit 4

in older Linux systems, runlevel not used/user definable, for special purposes

SysVinit

in older linux systems, the first process to run that starts and manages other processes and services during the boot process

systemctl isolate graphical.target

in systemd, command to change into the graphical target

systemctl isolate rescue.target

in systemd, command to change into the rescue target

systemctl isolate shutdown.target

in systemd, command to change into the shutdown target

systemctl disable httpd

in systemd, command to disable httpd service

systemctl list-units --type=target

in systemd, command to list active targets on the system (loaded and active)

systemctl list-units --type=service --all

in systemd, command to list all services on the system

systemctl list-unit-files --type=services

in systemd, command to list all services on the system and whether they are enabled

systemctl list-units --type=target --all

in systemd, command to list all targets on the system (loaded vs. not loaded, active vs. inactive)

systemctl list-dependencies multi-user.target

in systemd, command to list dependencies in multi-user.target

systemctl list-dependencies basic.target

in systemd, command to list dependencies of the basic target

systemctl list-units --type=service

in systemd, command to list services running on the system, active

systemctl is-enabled httpd

in systemd, command to see if httpd is enabled

systemctl list-unit-files --type=target --all

in systemd, lists an overview of targets on the system

multi-user.target

in systemd, similar to multi-user runlevel

upstart

initialization used by Ubuntu 14 and newer initialization service, launches services in parallel, backwards compatible with SysVinit

upstart startup scripts

jobs

initctl list

lists all jobs or services managed by upstart

/etc/init/

location of jobs in both old SysVinit and upstart

/usr/lib/systemd/

location/path of systemd files

/usr/lib/systemd/user/

location/path of user target files

exec

section in .conf file that defines the job that is to be run if the event criteria is met, loading the process into the current run session

stanza

sections in .conf files

Ctrl-d

sends a wall message

systemctl isolate

similar to telinit in SysVinit systems, in systemd used to go in and out of target modes

systemd

system initialization in Fedora, Centos 7, Red Hat 7, Debian 7, Ubuntu 15, and Arch Linux manages all other daemons and services on the system, first process to load on boot, no start up scripts or jobs

journalctl -xn

view the most recent information that's gone through the system file

restart ssh

using upstart, what is the command used to restart a service such as ssh

runlevel

command to display the current run level

systemctl -t help

command to list types of units

systemctl get-default

command to show the default target that we are working in

wall -n

command used to broadcast messages and suppresses the from user

wall

command used to broadcast messages to other users on the system

telinit

command used to change the current runlevel

systemctl set-default graphical.target

command used to change the default.target

init-checkconf test.conf

command used to verify the syntax of the job test.conf

service ssh restart

old command used to restart a service such as ssh

events

upstart listens for _______ to occur to trigger a process or service to start

journald

used by systemd to monitor events and loggings on the system