Sec. 39. System INIT Flashcards

(47 cards)

1
Q

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

A

/sbin/init

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2
Q

where is the int file located ?

A

/sbin/int

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3
Q

init works with the kernel to clean up processes

when they have ____________.

A

ended/terminate

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4
Q

init _____________ the later stages of the boot process .

A

coordinates

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5
Q

what are two startup alternatives?

A
  1. Upstart
  2. systemd
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6
Q

Instead of bash scripts, systemd uses _____________.

A

.service files.

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7
Q

systemd

Swap units

A

Swap units,

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

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8
Q

the _____ program is emutated to work with runlevels .

A

telinit

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9
Q

systemd

socket units

A

Socket units,

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

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10
Q

Name some features of systemd and session manager:

A
  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
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11
Q

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

A

deamons

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12
Q

systemd

device units

A

Device units,

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

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13
Q

systemd

Path units

A

Path units,

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

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14
Q

With systemd what is the main utility for managing services?

A

systemctl

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15
Q

systemd

Target units

A

Target unit ,

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

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16
Q

systemd

Slice units

A

Slice units,

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

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17
Q

what is the syntax of the systemctl command ?

A

systemctl [options] command [name]

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18
Q

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

A

$ systemctl

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19
Q

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

I do?

A

$ systemctl list-units -t service –all

20
Q

systemd

timer units

A

Timer units,

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

21
Q

systemctl

A
  • 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
22
Q

list-units for systemctl

A
  • list-units
    • list units that systemd currently has in memory.
    • This includes units that are either referenced directly or through a dependency.
23
Q

define runlevel 1

A

single user mode

24
Q

list-sockets for systemctl

A
  • 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.
25
# systemd ***Service units***
**Service unit** , which start and control daemons and processes they consist of .
26
# SysV **telinit**
-change SysV runlevel
27
define **runlevel** 0
shutdown the system adn turn power off
28
**telinit** Description
* 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.
29
**wall**
* 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.
30
describe the effect of the option **list-timers** for the command **systemctl**
**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
31
**loginctl**
* 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
32
# SysV **runlevel**
* 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.
33
what directory contains the System V init scripts?
**/etc/init.d**
34
**runlevel**
**runlevels** which define different system states .
35
define **runlevel** 2
Multiple user mode, no NFS , only text login
36
what is the number range for **runlevels**?
0-6
37
define **runlevel** 3
Multiple user ,*with* NFS, only test login
38
Define **runlevel 4**
not used
39
define **runlevel 5**
Mult
40
**init**
* 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**
41
what are the for phases of the boot process ?
1. the bootstrap phase 2. the bootloader phase 3. the kernel phase 4. system initialization
42
the filesystem drivers for GRUB may be found where?
**/boot/grub**
43
the GRUB menu is configured from what defualt GRUB configuration file? some distributions use what alternate value?
**/boot/grub/menu.lst** **/boot/grub/grub.conf**
44
the **grub.conf** file is seperated into what two files ?
1. gobal 2. title
45
how does GRUB access device names?
**GRUB** accesses devices via the BIOS
46
What is the syntax for naming a device in the **grub.conf** file?
\<**device\_type**\>\<**drive\_number\>**
47
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