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
