101.2 Boot the System (Boot Process - systemd and upstart - Power on to System Prompt) Flashcards
systemd
default on most modern Linux distributions
systemd
systemd
systemd was designed to replace the “__” mehod of managing system init and startup
sysvinit
systemd
systemd is more efficient and allows
parallel operation
systemd
has fewer
dependencies
systemd
service prioritization and
precedence
systemd
reduces “______” time
startup
systemd
units replace sysvinit
init scripts
systemd
‘name.service’ rather than
init script name
systemd major components
manager for services and systems
systemd
systemd major components
primary command for controlling service start/stop/restart/status
systemctl
systemd major components
display performance info on system bootup and allows for trace/debugging info
systemd-analyze
systemd major components
replaces consolekit, supports X Windows manager
logind
systemd major components
console daemon that replaces virtual terminals
consoled
systemd major components
logging system uses binary logs and is replaceable by other logging systems
journald
systemd major components
networking support daemon
networkd
systemd runlevels
indicated in component groups
cgroup
systemd units
the units insalled
/usr/lib/systemd/system
systemd units
units that have priority over other units are controlled by sysadmin
/etc/systemd/system
systemd units
units created at runtime and may have priority over non-runtime or installed units
/run/systmd/system
systemd service target dependencies
method of inidicating dependency units or groups of units
on the system
systemd service target dependencies
Requires
once requirement is met any other ‘wanted’ units started
systemd service target dependencies
only executed upon completion of any other ‘wanted units
/usr/lib/systemd/system/graphical.target
example
systemd boot process changes
not read and no longer in use
/etc/inittab
systemd boot process changes
a tree of ‘requires’ and ‘wants’ is followed
throughout process