enterprise linux 7 new feature_systemd_booting

Enterprise Linkx 7 New FeatureRHEL , OEL , CentOS , Fedora

Suk Kim , Oracle ACE Director

Nobreak Senior managed Consultant

Copyright 2016 All Right Reversed Nobreak Co.,LTD. Reproduction is strictly PROHIBITED

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Contacts : [email protected]

systemd systemd systemd init (systemd vs. init) , , , / systemd-analyze


( nick : )

) ( Oracle ACE Director )

) /

) IT

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)

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) IT

Service Management AND Boot Troubleshooting


introduce to systemd

init

init

pid 1 systemd

systemd

) Linux control groups

/etc/system /etc/sysconfig


systemd [root@el7 /]# systemctl -t help

Available unit types:

service

socket

target

device

mount

automount

snapshot

timer

swap

path

slice

scope


systemd

Service unit .service

Target unit .target systemd

Automount unit .automount

Device unit .device

Mount unit .mount

Path unit .path

Scope unit .scope

Slice unit .slice

Snapshot unit .snapshot systemd

Socket unit .socket

Swap unit .swap

Timer unit .timer systemd


systemd unit

[root@el7 ~]# systemctl

[root@el7 ~]# systemctl --type=service

failed , maintenance ( -l : full output)

[root@el7 ~]# systemctl status avahi-daemon.service -l


systemd unit

[root@el7 ~]# systemctl is-active sshdactive[root@el7 ~]# systemctl is-enabled sshdenabled

( --all : inactive unit )

[root@el7 ~]# systemctl list-units --type=service[root@el7 ~]# systemctl list-units --type=service all

/

[root@el7 ~]# systemctl list-unit-files [root@el7 ~]# systemctl list-unit-files --type=service

# systemctl --failed --type=service


Systemd init

Single User Mode ( : 1 )

[root@el7 ~]# systemctl rescue

Multi User Mode ( : 3)

[root@el7 ~]# systemctl isolate multi-user.target[root@el7 ~]# systemctl isolate runlevel3.target

graphical.target multi-user.target graphical.target .


Multi User Mode ( : 5)

[root@el7 ~]# systemctl isolate graphical.target[root@el7 ~]# systemctl isolate runlevel5.target

[root@el7 ~]# systemctl get-default graphical.target[root@el7 ~]# systemctl set-default multi-user.target[root@el7 ~]# systemctl get-default multi-user.target


Systemd target vs. SysV Runlevels

0 runlevel0.target , poweroff.target .

1 runlevel1.target , rescue.target .

2 runlevel2.target , multi-user.target .

(non-graphical)


(non-graphical)


(non-graphical)

5 runlevel5.target , graphical.target .

6 runlevel6.target , reboot.target .


Systemd vs. init command

runlevel systemctl list-units --type target .

telinit runlevel systemctl isolate name .target .

runlevel systemd

isolate target .

AllowIsolate=yes ( ex : graphical.target )crtyptsetup.target isolate .


power-off

[root@el7 ~]# systemctl poweroff

emergency (rescue , root )

[root@el7 ~]# systemctl emergency

halt ( , )

[root@el7 ~]# systemctl halt

reboot ()

[root@el7 ~]# systemctl reboot

suspend ( )

[root@el7 ~]# systemctl suspend

hibernate ( )

[root@el7 ~]# systemctl hibernate


halt systemctl halt

poweroff systemctl poweroff .

reboot systemctl reboot

pm-suspend systemctl suspend

pm-hibernate systemctl hibernate

pm-suspend-hybrid systemctl hybrid-sleep


[root@el7 ~]# systemctl list-unit-files

[root@el7 ~]# systemctl list-sockets


[root@el7 ~]# systemctl --failed

/

[root@el7 ~]# systemctl list-dependencies swap.target

/ ( --reverse )

[root@el7 ~]# systemctl list-dependencies sshd.service reverse


[root@el7 ~]# systemctl enable sshd

[root@el7 ~]# systemctl disable sshd

[root@el7 ~]# systemctl start sshd

[root@el7 ~]# systemctl stop sshd

[root@el7 ~]# systemctl restart sshd

[root@el7 ~]# systemctl reload sshd


(is-enabled)

[root@el7 ~]# systemctl is-enabled sshd

(is-active)

[root@el7 ~]# systemctl is-active sshd

[root@el7 ~]# systemctl reenable sshd

[root@el7 ~]# systemctl daemon-reload

[root@el7 ~]# systemctl daemon-reexcute

kill

[root@el7 ~]# systemctl kill httpd


[root@el7 ~]# systemctl mask network

[root@el7 ~]# systemctl unmask network

disable . . .

( ex. network vs NetworkManager)


( -l : )

[root@el7 ~]# systemctl status sshd


Loaded

.

,

.

Active

Main PID PID

Status .

Process .

CGroup Control Group .


systemctl summary vs. service utility

systemctl

service name start systemctl start name .service

service name stop systemctl stop name .service

service name restart systemctl restart name .service

Service name condrestart systemctl try-restart name .service

service name reload systemctl reload name .service

service name status systemctl status name .service

systemctl is-active name .service

service --status-all systemctl list-units --type service --all

chkconfig name on systemctl enable unit

chkconfig name off systemctl disable unit

systemctl mask unit ,

systemctl unmask unit mask

systemctl list-dependencies unit ,


systemctl vs. chkconfig utility

chkconfig systemctl

chkconfig name on systemctl enable name .service .

chkconfig name off systemctl disable name .service .

chkconfig --list namesystemctl status name .service

systemctl is-enabled name .service

.

chkconfig --list systemctl list-unit-files --type service .


Systemd

/usr/lib/systemd/system/ RPM systemd

/run/systemd/system/ systemd , .

/etc/systemd/system/ systemd unit. unit .


( System V Boot Process )

BIOS/UEFI

GRUB/LILO

KERNEL

init

Read inittab

rc.sysint

Run level 1

Run level 2

Run level 3

Run level 4

Run level 5


symlink

symlink

( Systemd Boot Process )

BIOS/UEFI

GRUB/LILO

KERNEL

systemd

Default target

rescue target

unit

sysinit target

unit

basic target

unit

multi-user target

unit


UEFI or BIOS

MBR or UEFI boot firmware

System firmware reads -> boot loader ( grub2 )#grub2-install

/etc/grub.d/ , /etc/default/grub , /boot/grub2/grub.cfg

initramfs kernel #/etc/dracut.conf

initramfs ,

/etc/grub.d/ , /etc/default/grub , /boot/grub2/grub.cfg

dracut initramfs low-level #man dracut


(initramfs )PID 1 /sbin/init ( RHEL 7 udev daemon /sbin/init systemd )

initramfs systemd initrd.target , /sysroot root file system

/sysroot initramfs systemd systemd

systemd -> default target , / ( )

/etc/system/system/default/target, /etc/system/system


Systemd init

systemd-journal

Journalctl Syslog , ,

[root@el7 ~]# journalctl-- Logs begin at 2015-02-14 01:33:52 KST, end at 2015-02-15 01:20:01 KST. --2 14 01:33:52 localhost systemd-journal[62]: Runtime journal is using 8.0M (max 184.5M, leaving 276.7M of free 1.7G, curre2 14 01:33:52 localhost systemd-journal[62]: Runtime journal is using 8.0M (max 184.5M, leaving 276.7M of free 1.7G, curre2 14 01:33:52 localhost kernel: Initializing cgroup subsys cpuset2 14 01:33:52 localhost kernel: Initializing cgroup subsys cpu2 14 01:33:52 localhost kernel: Linux version 3.8.13-35.3.1.el7uek.x86_64 ([email protected]) (gcc versio2 14 01:33:52 localhost kernel: e820: BIOS-provided physical RAM map:2 14 01:33:52 localhost kernel: BIOS-e820: [mem 0x0000000000000000-0x000000000009efff] usable2 14 01:33:52 localhost kernel: BIOS-e820: [mem 0x000000000009f000-0x000000000009ffff] reserved2 14 01:33:54 localhost kernel: sd 2:0:0:0: [sda] Assuming drive cache: write through2 14 01:33:54 localhost kernel: sd 2:0:0:0: [sda] Cache data unavailable2 14 01:33:54 localhost kernel: sd 2:0:0:0: [sda] Assuming drive cache: write through


Journalctl

red color bold

root

adm .

Journal Persitent storage


( -n : )

[root@el7 ~]# journalctl n 10

[root@el7 ~]# journalctl o verbose

Liveview

[root@el7 ~]# journalctl f

(-p : : debug~emerg)

[root@el7 ~]# journalctl p err

system.journal-fields(7)


(-b : )

[root@el7 ~]# journalctl -b

(--since , --until : )

[root@el7 ~]# journalctl --since=2015-01-01 --until=2015-01-31

[root@el7 ~]# journalctl -p warning --since = "2013-3-16 23:59:59"

(-p : : debug~emerg)

[root@el7 ~]# journalctl p err

system.journal-fields(7)


( )

[root@el7 ~]# journalctl /sbin/sshd

(Logical AND )

[root@el7 ~]# journalctl -F -F

(Logical OR )

[root@el7 ~]# journalctl -F = + =

)

[root@el7 ~]# journalctl _UID = 70 _SYSTEMD_UNIT = avahi-daemon.service _SYSTEMD_UNIT = crond.service


Persistent Storage /run/log/journal /run/log/journal ,

/var/log/journal

Persistent Storage /

: , journal

: ,


Persistent (

[root@el7 ~]# mkdir -p /var/log/journal

[root@el7 ~]# systemctl restart system-jounald

[root@el7 ~]# mkdir -p -m 2775 /var/log/journal[root@el7 ~]# chown :systemd-journal /var/log/journal/[root@el7 ~]# killall -USR1 systemd-journald


GUI # yum -y install gnome-system-log

root


GUI -


Systemd Cgroup

Systemd Cgroup ( Control Group )

Cgroup

[root@el7 ~]# system-cgls


Systemd Cgroup

Systemd Cgroup ( Control Group )

Cgroup top

[root@el7 ~]# system-cgtop


Systemctl

http.service CPUShare 512

[root@el7 ~]# systemctl set-property sshd.service CPUShares=512

http.service

[root@el7 ~]# systemctl show httpd.service CPUShares

[root@el7 ~]# systemctl show sshd.service | grep CPUCPUShares=1024[root@el7 ~]# systemctl set-property sshd.service CPUShares=512[root@el7 ~]# systemctl show sshd.service | grep CPUCPUShares=512[root@el7 ~]# cat /sys/fs/cgroup/cpu/system.slice/sshd.service/cpu.shares512

[root@el7 ~]# man systemd.resource-control


Systemd (/)

[root@el7 ~]# hostnamectl

[root@el7 ~]# hostnamectl set-hostname newlinux

[root@el7 ~]# localectl

[root@el7 ~]# localectl set-locale LANG=ko_KR.UTF-8

localectl list-keymaps set-keymap set-x11-keymap list-locales set-locale status


Systemd ()

(systemd )

[root@el7 ~]# loginctl

loginctl

[root@el7 ~]# loginctl list-users

terminate-userunlock-sessionuser-status

activateattachdisable-lingerenable-lingerflush-deviceskill-session

kill-user list-seatslist-sessionslist-userslock-sessionseat-status

session-status show-seat show-session show-user terminate-seat terminate-session


Systemd ()

(RTC) (UTC) UTC (DST) UTC

,


Systemd ()

[root@el7 ~]# timedatectl

[root@el7 ~]# timedatectl set-time 2015-02-15

( HH:MM:SS )

[root@el7 ~]# timedatectl set-time 12:30:00

( RTC : true(1) , false(0) )

[root@el7 ~]# localectl set-local-rtc true

[root@el7 ~]# localectl list-timezone

( RTC : true(1) , false(0) )

[root@el7 ~]# localectl set-timezone Asia/Seoul


Systemd ( )

[root@el7 ~]#hostnamectl -H [email protected] set-hostname newlinux

[root@el7 ~]# hostnamectl -H [email protected]

mailto:[email protected]:[email protected]


boot taget (rescue.target )

1. e .

2. linux16

3. systemd.unit=rescue.target

4. ctrl + x


root password

1. e .

2. linux16

3. rd.break

4. ctrl + x

5. # mount -o remount,rw /sysroot

6. # chroot /sysroot

7. # passwd root

8. # touch /.autorelabel


debug shell

crtl + alt + F9

Debug Shell

[root@el7 ~]# systemctl enable debug-shell.serviceln -s '/usr/lib/systemd/system/debug-shell.service' '/etc/systemd/system/sysinit.target.wants/debug-shell.service'

debug shell root .


Systemd systemd-analyze time

system-analyze time

RAM(initrd) ( ) (spawned) , .


Systemd

systemd-analyze time

systemd-analyze time

[root@el7 ~]# systemd-analyze Startup finished in 1.502s (kernel) + 3.274s (initrd) + 26.716s (userspace) = 31.493s


Systemd

systemd-analyze blame . , .

systemd-analyze blame

[root@el7 ~]# systemd-analyze blame 12.945s kdump.service4.579s firewalld.service3.748s network.service2.920s tuned.service2.829s postfix.service1.957s iprupdate.service


Systemd

systemd-analyze critical-chain @ , "+" .

systemd-analyze critical-chain

[[root@el7 ~]# systemd-analyze critical-chain multi-user.target @26.690skdump.service @13.744s +12.945snetwork.target @13.710snetwork.service @9.960s +3.748sNetworkManager.service @8.652s +1.303s


Systemd

systemd-analyze plot SVG . , .

systemd-analyze plot

[[root@el7 ~]# systemd-analyze plot > analyze.svg


Systemd

systemd-analyze dotGraphViz dot GraphViz ( #yum -y install GraphViz )

eyes of gnome (#yum -y install eog)

systemd-analyze dot

[[root@el7 ~]# systemd-analyze dot 'avahi-daemon.*' | dot -Tsvg > avahi.svg


Systemd

Color legend: black = Requiresdark blue = Requisitedark grey = Wantsred = Conflictsgreen = After

systemd-analyze dot avahi-daemon


Systemd

systemd-analyze dot

[[root@el7 ~]# systemd-analyze dot --to-pattern='*.target' --from-pattern='*.target' | dot -Tsvg > targets.svg

systemd-analyze dot target unit

1 Service Management AND Boot Troubleshootingintroduce to systemd systemd systemd systemd unit systemd unit Systemd target vs. SysV RunlevelsSystemd vs. init command systemctl summary vs. service utilitysystemctl vs. chkconfig utilitySystemd ( System V Boot Process ) ( Systemd Boot Process ) GUI GUI - Systemd Cgroup Systemd Cgroup Systemd (/)Systemd ()Systemd ()Systemd ()Systemd ( )Systemd Systemd Systemd Systemd Systemd Systemd Systemd Systemd

enterprise linux 7 new feature_systemd_booting

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