Sec. 39. System INIT

Question 1

What is the first user-level process/task run on the system?

Answer 1

/sbin/init

Question 2

where is the int file located ?

Answer 2

/sbin/int

Question 3

init works with the kernel to clean up processes

when they have ____________.

Answer 3

ended/terminate

Question 4

init _____________ the later stages of the boot process .

Answer 4

coordinates

Question 5

what are two startup alternatives?

Answer 5

1. Upstart
2. systemd

Question 6

Instead of bash scripts, systemd uses _____________.

Answer 6

.service files.

Question 7

systemd

Swap units

Answer 7

Swap units,

are very similar to mount units and encapsulate memory swap partitions or files of the operating system.

Question 8

the _____ program is emutated to work with runlevels .

Answer 8

telinit

Question 9

systemd

socket units

Answer 9

Socket units,

which encapsulate local IPC or network sockets in the system, useful for socket-based activation.

Question 10

Name some features of systemd and session manager:

Answer 10

1. boots faster than previous init systems
2. provides aggressive parallelizationcapabilities
3. uses socket and D-bus activation for starting services
4. Replaces shell script with programs
5. Offers on-demand starting of deamons
6. keeps tracks of processes using cgroups
7. Maintains mount and automount points

Question 11

Systemd sorts all ________ into their own Linux cgroups(control groups)

Answer 11

deamons

Question 12

systemd

device units

Answer 12

Device units,

expose kernel devices in systemd and may be used to implement device-based activation.

Question 13

systemd

Path units

Answer 13

Path units,

may be used to ativate other services when file system objects change or are modified.

Question 14

With systemd what is the main utility for managing services?

Answer 14

systemctl

Question 15

systemd

Target units

Answer 15

Target unit ,

are useful to group units, or provide well-known synchronization points furing boot-up

Question 16

systemd

Slice units

Answer 16

Slice units,

may be used to group units which mange system processes in a hierarchical tree for resource management purposes.

Question 17

what is the syntax of the systemctl command ?

Answer 17

systemctl [options] command [name]

Question 18

How would I see/show the status of everything that systemctl controls?

Answer 18

$ systemctl

Question 19

If I wanted to show all available services using systemctl what would

I do?

Answer 19

$ systemctl list-units -t service –all

Question 20

systemd

timer units

Answer 20

Timer units,

are useful for triggering avtivation of other units based on timers .

Question 21

systemctl

Answer 21

• 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

Question 22

list-units for systemctl

Answer 22

• list-units
  
  • ​list units that systemd currently has in memory.
  • This includes units that are either referenced directly or through a dependency.

Question 23

define runlevel 1

Answer 23

single user mode

Question 24

list-sockets for systemctl

Answer 24

• ​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.

Question 25

# systemd ***Service units***

Answer 25

**Service unit** , which start and control daemons and processes they consist of .

Question 26

# SysV **telinit**

Answer 26

-change SysV runlevel

Question 27

define **runlevel** 0

Answer 27

shutdown the system adn turn power off

Question 28

**telinit** Description

Answer 28

* Description: * **telinit** may be used to change SysV system runlevel. since the concept of SysV runlevels is obsolete the runlevel requests will be transparnently translated into systemd unit activation requests.

Question 29

**wall**

Answer 29

* Name: * **wall** - write a message to all users * Synopsis: * **wall** *[-n] [-t timeout] [-g group] [message \ file]* * Description: * **wall** displays a message , or the contents of a file, or otherwise its standard input, o the terminals of all cuurntly logged inusers.

Question 30

describe the effect of the option **list-timers** for the command **systemctl**

Answer 30

**list-timers** option will list timer units currently in memory, ordered by the time they elapse next. * *Understanding output:* * **NEXT** - shows the next time the timer will run * **LEFT** - shows how long till the next time the timer runs * **LAST** - show the last time the timer ran * **PASSED** - show how long has passsed since the timer last ran * **UNIT** - shows teh name of the timer * **ACTIVATES** - shows the name the service the tmer activates when it runs

Question 31

**loginctl**

Answer 31

* Name: * **loginctl** - Control the systemd login manager * Synopsis: * **loginctl** *[options...] {command} [Name...]* * Description: * **loginctl** may be used to introspect and contro the state of **systemd** login manager

Question 32

# SysV **runlevel**

Answer 32

* Name * **runlevel** - Print previous and current SysV runlevel * Synopsis: * **runlevel** *[options...]* * Description: * "**Runlevels**" are an ***abosolete*** way to start and stop groups of services used in **SysV init**. * **systemd** provides compatibility layer thatmaps runlevels to targets, and associated binaries lik runlevel. * Nevertheless, only **one** runlevel can be "active" at a given time.

Question 33

what directory contains the System V init scripts?

Answer 33

**/etc/init.d**

Question 34

**runlevel**

Answer 34

**runlevels** which define different system states .

Question 35

define **runlevel** 2

Answer 35

Multiple user mode, no NFS , only text login

Question 36

what is the number range for **runlevels**?

Answer 36

0-6

Question 37

define **runlevel** 3

Answer 37

Multiple user ,*with* NFS, only test login

Question 38

Define **runlevel 4**

Answer 38

not used

Question 39

define **runlevel 5**

Answer 39

Mult

Question 40

**init**

Answer 40

* configures all aspects of the environment * **executes** the **later** stages of the **boot process** * starts processes needed to login to the system. * located in **/sbin/init**

Question 41

what are the for phases of the boot process ?

Answer 41

1. the bootstrap phase 2. the bootloader phase 3. the kernel phase 4. system initialization

Question 42

the filesystem drivers for GRUB may be found where?

Answer 42

**/boot/grub**

Question 43

the GRUB menu is configured from what defualt GRUB configuration file? some distributions use what alternate value?

Answer 43

**/boot/grub/menu.lst** **/boot/grub/grub.conf**

Question 44

the **grub.conf** file is seperated into what two files ?

Answer 44

1. gobal 2. title

Question 45

how does GRUB access device names?

Answer 45

**GRUB** accesses devices via the BIOS

Question 46

What is the syntax for naming a device in the **grub.conf** file?

Answer 46

\<**device\_type**\>\<**drive\_number\>**

Question 47

+