Sec. 39. System INIT Flashcards
(47 cards)
What is the first user-level process/task run on the system?
/sbin/init
where is the int file located ?
/sbin/int
init works with the kernel to clean up processes
when they have ____________.
ended/terminate
init _____________ the later stages of the boot process .
coordinates
what are two startup alternatives?
- Upstart
- systemd
Instead of bash scripts, systemd uses _____________.
.service files.
systemd
Swap units
Swap units,
are very similar to mount units and encapsulate memory swap partitions or files of the operating system.
the _____ program is emutated to work with runlevels .
telinit
systemd
socket units
Socket units,
which encapsulate local IPC or network sockets in the system, useful for socket-based activation.
Name some features of systemd and session manager:
- boots faster than previous init systems
- provides aggressive parallelizationcapabilities
- uses socket and D-bus activation for starting services
- Replaces shell script with programs
- Offers on-demand starting of deamons
- keeps tracks of processes using cgroups
- Maintains mount and automount points
Systemd sorts all ________ into their own Linux cgroups(control groups)
deamons
systemd
device units
Device units,
expose kernel devices in systemd and may be used to implement device-based activation.
systemd
Path units
Path units,
may be used to ativate other services when file system objects change or are modified.
With systemd what is the main utility for managing services?
systemctl
systemd
Target units
Target unit ,
are useful to group units, or provide well-known synchronization points furing boot-up
systemd
Slice units
Slice units,
may be used to group units which mange system processes in a hierarchical tree for resource management purposes.
what is the syntax of the systemctl command ?
systemctl [options] command [name]
How would I see/show the status of everything that systemctl controls?
$ systemctl
If I wanted to show all available services using systemctl what would
I do?
$ systemctl list-units -t service –all
systemd
timer units
Timer units,
are useful for triggering avtivation of other units based on timers .
systemctl
- systemctl —control the systemd system and service manager
- syntax—– systemctl [options] command [unit …]
- discription:
- –systemctl may be used to introspect and control the state fo the “systemd” system and service manager
list-units for systemctl
-
list-units
- list units that systemd currently has in memory.
- This includes units that are either referenced directly or through a dependency.
define runlevel 1
single user mode
list-sockets for systemctl
- list-sockets
- List socket unite currntly in memory, ordered by listening address.
- If one or more PATTERNs are specified only the socket units matching one of them are shown.