System Boot Method
V init
- 커널에 의해 init 프로그램이 제일 먼저 실행 (pid=1)
- init process: 순차처리
- 부팅 속도가 빨라지지 않음 -> Upstart로 변경
Upstart
- 마찬가지로 init process 사용
- 사실 이전과 큰 차이가 없다.
Systemd
-
CentOS 7,8버전에 해당
-
init process가 아닌, systemd process를 통해서 다른 process를 관리 처리하겠다고 변경
-
순차처리가 아닌, 병렬처리(Parallel) -> 부팅 속도 빨라짐
- 즉, systemd가 여러 process를 병렬로 처리하여 속도의 향상
- 만약 의존성 관계가 있으면 tree형태로 처리
[root@station14 ~]# pstree -p systemd(1)─┬─NetworkManager(871)─┬─dhclient(938) │ ├─{NetworkManager}(913) │ └─{NetworkManager}(915) ├─abrt-watch-log(821) ├─abrt-watch-log(857) ├─abrtd(819) ├─accounts-daemon(830)─┬─{accounts-daemon}(841) │ └─{accounts-daemon}(844) ├─acpid(868) ├─at-spi-bus-laun(1895)─┬─dbus-daemon(1900)───{dbus-daemon}(1901) │ ├─{at-spi-bus-laun}(1896) │ ├─{at-spi-bus-laun}(1897) │ └─{at-spi-bus-laun}(1899) ├─at-spi2-registr(1903)─┬─{at-spi2-registr}(1904) │ └─{at-spi2-registr}(1905) ├─atd(1146) ├─auditd(775)─┬─audispd(788)─┬─sedispatch(795) │ │ └─{audispd}(796) │ └─{auditd}(787) ├─automount(7447)─┬─{automount}(7448) │ ├─{automount}(7449) │ ├─{automount}(7452) │ ├─{automount}(7455) │ ├─{automount}(7456) │ └─{automount}(7457) ├─avahi-daemon(839)───avahi-daemon(845) ├─caribou(1993)─┬─{caribou}(1996) │ └─{caribou}(1999) ├─chronyd(846) ├─colord(1485)─┬─{colord}(1488) │ └─{colord}(1490) ├─crond(1144) ├─cupsd(1121) ├─dbus-daemon(1724)───{dbus-daemon}(1725) ├─dbus-daemon(810)───{dbus-daemon}(813) ├─dbus-launch(1723) ├─dconf-service(2384)─┬─{dconf-service}(2385) │ └─{dconf-service}(2386) ├─dnsmasq(1353)───dnsmasq(1354) ├─evolution-calen(2155)─┬─{evolution-calen}(2160) │ ├─{evolution-calen}(2162) │ ├─{evolution-calen}(2163) │ ├─{evolution-calen}(2164) │ └─{evolution-calen}(2167) ├─evolution-sourc(1964)─┬─{evolution-sourc}(1965) │ └─{evolution-sourc}(1966) ├─gconfd-2(2318) ├─gdm(1143)─┬─Xorg(1398)─┬─{Xorg}(1399) │ │ ├─{Xorg}(1400) │ │ └─{Xorg}(1401) │ ├─gdm-session-wor(1696)─┬─gnome-session(1716)─┬─abrt-applet(2043)─┬─{abrt-applet+ │ │ │ │ └─{abrt-applet+ │ │ │ ├─gnome-settings-(1912)─┬─{gnome-s+ │ │ │ │ ├─{gnome-s+ │ │ │ │ ├─{gnome-s+ │ │ │ │ └─{gnome-s+ │ │ │ ├─gnome-shell(1928)─┬─firefox(2261+ │ │ │ │ ├─ibus-daemon(+ │ │ │ │ ├─{gnome-shell+ │ │ │ │ ├─{gnome-shell+ │ │ │ │ ├─{gnome-shell+ │ │ │ │ ├─{gnome-shell+ │ │ │ │ └─{gnome-shell+ │ │ │ ├─gnome-software(2052)─┬─{gnome-so+ │ │ │ │ ├─{gnome-so+ │ │ │ │ └─{gnome-so+ │ │ │ ├─nautilus(2026)─┬─{nautilus}(2028+ │ │ │ │ ├─{nautilus}(2029+ │ │ │ │ └─{nautilus}(2068+ │ │ │ ├─seapplet(2032) │ │ │ ├─ssh-agent(1883) │ │ │ ├─tracker-extract(2046)─┬─{tracker+ │ │ │ │ ├─{tracker+ │ │ │ │ ├─{tracker+ │ │ │ │ ├─{tracker+ │ │ │ │ ├─{tracker+ │ │ │ │ ├─{tracker+ │ │ │ │ ├─{tracker+ │ │ │ │ ├─{tracker+ │ │ │ │ ├─{tracker+ │ │ │ │ ├─{tracker+ │ │ │ │ ├─{tracker+ │ │ │ │ ├─{tracker+ │ │ │ │ └─{tracker+ │ │ │ ├─tracker-miner-a(2047)─┬─{tracker+ │ │ │ │ └─{tracker+ │ │ │ ├─tracker-miner-f(2050)─┬─{tracker+ │ │ │ │ ├─{tracker+ │ │ │ │ └─{tracker+ │ │ │ ├─tracker-miner-u(2051)─┬─{tracker+ │ │ │ │ └─{tracker+ │ │ │ ├─{gnome-session}(1906) │ │ │ ├─{gnome-session}(1907) │ │ │ └─{gnome-session}(1908) │ │ ├─{gdm-session-wor}(1697) │ │ └─{gdm-session-wor}(1698) │ ├─{gdm}(1179) │ ├─{gdm}(1180) │ └─{gdm}(1397) ├─gnome-keyring-d(1706)─┬─{gnome-keyring-d}(1707) │ ├─{gnome-keyring-d}(1920) │ ├─{gnome-keyring-d}(1921) │ └─{gnome-keyring-d}(1922) ├─gnome-shell-cal(1957)─┬─{gnome-shell-cal}(1960) │ ├─{gnome-shell-cal}(1962) │ ├─{gnome-shell-cal}(1977) │ ├─{gnome-shell-cal}(1978) │ └─{gnome-shell-cal}(2153) ├─gnome-terminal-(16364)─┬─bash(16372)───pstree(7971) │ ├─gnome-pty-helpe(16371) │ ├─{gnome-terminal-}(16365) │ ├─{gnome-terminal-}(16366) │ └─{gnome-terminal-}(16367) ├─goa-daemon(1969)─┬─{goa-daemon}(1970) │ ├─{goa-daemon}(1972) │ └─{goa-daemon}(1973) ├─goa-identity-se(1976)─┬─{goa-identity-se}(1981) │ ├─{goa-identity-se}(1982) │ └─{goa-identity-se}(1983) ├─gpm(823) ├─gsd-printer(1932)─┬─{gsd-printer}(1933) │ └─{gsd-printer}(1934) ├─gssproxy(869)─┬─{gssproxy}(885) │ ├─{gssproxy}(886) │ ├─{gssproxy}(887) │ ├─{gssproxy}(888) │ └─{gssproxy}(889) ├─gvfs-afc-volume(2011)─┬─{gvfs-afc-volume}(2012) │ ├─{gvfs-afc-volume}(2013) │ └─{gvfs-afc-volume}(2015) ├─gvfs-goa-volume(2017)─┬─{gvfs-goa-volume}(2018) │ └─{gvfs-goa-volume}(2019) ├─gvfs-gphoto2-vo(2022)─┬─{gvfs-gphoto2-vo}(2023) │ └─{gvfs-gphoto2-vo}(2025) ├─gvfs-mtp-volume(2006)─┬─{gvfs-mtp-volume}(2007) │ └─{gvfs-mtp-volume}(2009) ├─gvfs-udisks2-vo(2001)─┬─{gvfs-udisks2-vo}(2002) │ └─{gvfs-udisks2-vo}(2003) ├─gvfsd(1792)─┬─{gvfsd}(1793) │ └─{gvfsd}(1794) ├─gvfsd-fuse(1797)─┬─{gvfsd-fuse}(1800) │ ├─{gvfsd-fuse}(1801) │ ├─{gvfsd-fuse}(1804) │ ├─{gvfsd-fuse}(1805) │ └─{gvfsd-fuse}(1811) ├─gvfsd-metadata(6761)─┬─{gvfsd-metadata}(6762) │ └─{gvfsd-metadata}(6763) ├─gvfsd-recent(2717)─┬─{gvfsd-recent}(2718) │ └─{gvfsd-recent}(2719) ├─gvfsd-trash(2094)─┬─{gvfsd-trash}(2097) │ └─{gvfsd-trash}(2098) ├─ibus-x11(1951)─┬─{ibus-x11}(1958) │ └─{ibus-x11}(1959) ├─irqbalance(817) ├─ksmtuned(882)───sleep(7962) ├─libvirtd(1131)─┬─{libvirtd}(1184) │ ├─{libvirtd}(1185) │ ├─{libvirtd}(1186) │ ├─{libvirtd}(1187) │ ├─{libvirtd}(1188) │ ├─{libvirtd}(1189) │ ├─{libvirtd}(1190) │ ├─{libvirtd}(1191) │ ├─{libvirtd}(1192) │ ├─{libvirtd}(1193) │ ├─{libvirtd}(1204) │ ├─{libvirtd}(1205) │ ├─{libvirtd}(1206) │ ├─{libvirtd}(1207) │ ├─{libvirtd}(1208) │ └─{libvirtd}(2862) ├─lsmd(836) ├─lvmetad(571) ├─master(1275)─┬─cleanup(7944) │ ├─local(7946) │ ├─pickup(7941) │ ├─qmgr(1277) │ └─trivial-rewrite(7945) ├─mcelog(870) ├─mission-control(1986)─┬─{mission-control}(1990) │ ├─{mission-control}(1994) │ └─{mission-control}(1995) ├─packagekitd(1554)─┬─{packagekitd}(1560) │ └─{packagekitd}(1561) ├─polkitd(801)─┬─{polkitd}(808) │ ├─{polkitd}(814) │ ├─{polkitd}(815) │ ├─{polkitd}(816) │ └─{polkitd}(820) ├─qemu-kvm(7074)─┬─{qemu-kvm}(7099) │ ├─{qemu-kvm}(7100) │ ├─{qemu-kvm}(7101) │ └─{qemu-kvm}(7970) ├─rngd(838) ├─rsyslogd(1117)─┬─{rsyslogd}(1133) │ └─{rsyslogd}(1134) ├─rtkit-daemon(809)─┬─{rtkit-daemon}(858) │ └─{rtkit-daemon}(859) ├─smartd(798) ├─sshd(1118) ├─systemd-journal(550) ├─systemd-logind(800) ├─systemd-machine(7075) ├─systemd-udevd(590) ├─tracker-store(2038)─┬─{tracker-store}(2042) │ ├─{tracker-store}(2044) │ ├─{tracker-store}(2045) │ ├─{tracker-store}(2054) │ ├─{tracker-store}(2055) │ ├─{tracker-store}(2056) │ └─{tracker-store}(2057) ├─tuned(1119)─┬─{tuned}(1215) │ ├─{tuned}(1216) │ ├─{tuned}(1217) │ └─{tuned}(1218) ├─udisksd(1576)─┬─{udisksd}(1579) │ ├─{udisksd}(1581) │ ├─{udisksd}(1602) │ └─{udisksd}(1606) ├─upowerd(1454)─┬─{upowerd}(1455) │ └─{upowerd}(1456) ├─virt-manager(2752)─┬─{virt-manager}(2756) │ ├─{virt-manager}(2757) │ ├─{virt-manager}(2758) │ ├─{virt-manager}(2759) │ ├─{virt-manager}(7103) │ └─{virt-manager}(7104) ├─virtlogd(2776)───{virtlogd}(2778) ├─wpa_supplicant(1546) └─xinetd(1122)
systemd
- system 뿐만 아니라 service까지 관리
- daemon
- systemd 를 관리하는 컨트롤러 : systemctl
- systemd의 핵심 키워드 :
- 1) target : run level
- 2) unit : script
runlevel
- 비슷한 작업을 하는 unit들(script들)의 묶음 : target
- 즉, runlevel == target
- Runlevel-Target
- 0-poweroff.target -> halt
- 1-rescue.target -> Single-user mode
- 2-multi-user.target -> Full multi-user without networking
- 3-multi-user.target -> Full multi-user with text mode login
- 4-multi-user.target -> custom or local
- 5-graphical.target -> Full multi-user with graphical login
- 6-reboot.target -> reboot
[root@localhost]# who -r run-level 5 2023-04-17 11:17 [root@localhost]# runlevel N 5 > runlevel 3으로 변경 [root@localhost]# init 3 [root@localhost]# runlevel 5 3 > runlevel 1으로 변경 [root@localhost]# init 1 [root@localhost]# runlevel 3 1 [root@localhost]# runlevel [root@localhost]# systemctl isolate graphical.target [root@localhost]# who -r run-level 5 2023-04-18 11:01 last=1
default boot target 확인 가능
[root@localhost] systemctl get-default
default boot target 설정 가능
[root@localhost] systemctl set-default multi-user.target
재부팅해보자 (reboot, or init 6 입력)
부트로더 : 커널 & 램디스크 로딩
- GRUB
- 커널 & 램디스크를 메모리로 로딩
- systemd가
- systemd에 의해 나머지 process들이 병렬로 처리
-
단계
-
부트로더 설정파일
- linux16 행 -> 커널 관련 설정
- utf-8뒤에 rd.break 추가 : 커널 램디스크 로딩되자마자 멈춘다.
- initrd16 행 -> 램디스크 관련 설경
- linux16 행 -> 커널 관련 설정
-
root 디렉토리 변경
- mount -o rw,remount /sysroot
- chroot /sysroot
- ls --- 평소에 보던 root 디렉토리가 출력됨.
-
passwd -- 비밀번호 변경
-
장애처리 복구
- vi /etc/fstab -> LVM관련 실습 코드 삭제 (부팅 지연된 이유:LVM 다 삭제했는데 fstab에는 남아있어서 부팅하기 전에 계속 시도하는 것)
-
세팅했던 내용이 적용될 수 있도록 해당 파일 꼭 작성 필요함.
- touch /.autorelabel
-
부팅과 서비스
-
Listing and Service (system 부팅 시 service 활성화되는지 아닌지 목록 확인)
- systemctl list-unit-files --type=service
- static -> 특정 서비스에 종속되어 있는 것
- systemctl list-unit-files --type=service
-
Start and Stop Service
- service 서비스명 start|stop|status
- /etc/init.d/스크립트명
-
Enabling and Disablig a service
- chkconfig 서비스명 on|off
- ntsysv
- setup
Booting Linux on PC
- 전원 ON
- ROM : BIOS/UEFI
- 부트로더의 커널, 램디스크 로딩
- 부팅매체 : 하드디스크 드라이브 (HDD)
- MBR, GPT -> 부트로더(lilo, GRUB(v1.x,v2.x))
- 부트로더의 역할 : 커널 & 램디스크를 메모리로 로딩 (-> systemd, init)
- systemd 실행 후, 여러 프로세스 병렬 처리
부트로더가 깨졌을 때
grub2-install /dev/vda
실행 시, 부트로더 다시 install
부트로더 다시 설정해야할 때
- 가정
- LAN 카드이름 : eth(x) -> en(o|s|pxsx)
- 카드 이름이 바뀌어서 변경해야할 경우?
- 템플릿 파일 편집: /etc/defaults/grub
- grub2-mkconifg를 통해
- /boot/grub2grub.cfg(BIOS/MBR boot) 또는 /boot/efi/EFI/distro.grub.cfg(UEFI/GPT boot) 에 반영
vi /etc/default/grub
grub2-mkconfig -o /boot/grub2/grub.cfg
> 재부팅 후 ifconfig로 inet6 부분 삭제 확인
> 커널에 전달된 명령어 조회 가능
cat /proc/cmdline RAM disk
[root@station14 ~]# ls -l /boot
total 119432
-rw-r--r--. 1 root root 137701 Jun 30 2017 config-3.10.0-514.26.1.el7.x86_64
drwxr-xr-x. 2 root root 27 Apr 8 05:27 grub
drwx------. 6 root root 111 Apr 8 05:41 grub2
-rw-------. 1 root root 64540882 Apr 8 05:37 initramfs-0-rescue-2544d59d80f44d02b6ae0264364abe2e.img
-rw-------. 1 root root 33206678 Apr 8 05:41 initramfs-3.10.0-514.26.1.el7.x86_64.img
-rw-r--r--. 1 root root 10210059 Apr 8 05:36 initrd-plymouth.img
-rw-r--r--. 1 root root 277955 Jun 30 2017 symvers-3.10.0-514.26.1.el7.x86_64.gz
-rw-------. 1 root root 3114429 Jun 30 2017 System.map-3.10.0-514.26.1.el7.x86_64
-rwxr-xr-x. 1 root root 5397328 Apr 8 05:37 vmlinuz-0-rescue-2544d59d80f44d02b6ae0264364abe2e
-rwxr-xr-x. 1 root root 5397328 Jun 30 2017 vmlinuz-3.10.0-514.26.1.el7.x86_64
[root@station14 ~]# rm -f /boot/initramfs-3.10.0-514.26.1.el7.x86_64.img
[root@station14 ~]# dracut --regenerate-all
[root@station14 ~]# ls -l /boot/
total 117028
-rw-r--r--. 1 root root 137701 Jun 30 2017 config-3.10.0-514.26.1.el7.x86_64
drwxr-xr-x. 2 root root 27 Apr 8 05:27 grub
drwx------. 6 root root 111 Apr 8 05:41 grub2
-rw-------. 1 root root 64540882 Apr 8 05:37 initramfs-0-rescue-2544d59d80f44d02b6ae0264364abe2e.img
-rw-------. 1 root root 30745655 Apr 18 14:00 initramfs-3.10.0-514.26.1.el7.x86_64.img
-rw-r--r--. 1 root root 10210059 Apr 8 05:36 initrd-plymouth.img
-rw-r--r--. 1 root root 277955 Jun 30 2017 symvers-3.10.0-514.26.1.el7.x86_64.gz
-rw-------. 1 root root 3114429 Jun 30 2017 System.map-3.10.0-514.26.1.el7.x86_64
-rwxr-xr-x. 1 root root 5397328 Apr 8 05:37 vmlinuz-0-rescue-2544d59d80f44d02b6ae0264364abe2e
-rwxr-xr-x. 1 root root 5397328 Jun 30 2017 vmlinuz-3.10.0-514.26.1.el7.x86_64
[root@station14 ~]# mkdir /tmp/ram
[root@station14 ~]# cd /tmp/ram/
[root@station14 ram]# /lib/dracut/skipcpio /boot/initramfs-3.10.0-514.26.1.el7.x86_64.img | zcat | cpio -icdmu
131313 blocks
[root@station14 ram]# ls
bin etc lib proc run shutdown sysroot usr
dev init lib64 root sbin sys tmp var
> target들 간의 연간관계 확인
[root@station14 ram]# systemctl list-dependencies
default.target
● ├─accounts-daemon.service
● ├─gdm.service
● ├─network.service
● ├─rtkit-daemon.service
● ├─systemd-readahead-collect.service
● ├─systemd-readahead-replay.service
● ├─systemd-update-utmp-runlevel.service
● └─multi-user.target
● ├─abrt-ccpp.service
● ├─abrt-oops.service
● ├─abrt-vmcore.service
● ├─abrt-xorg.service
● ├─abrtd.service
● ├─acpid.service
● ├─atd.service
● ├─auditd.service
● ├─autofs.service
● ├─avahi-daemon.service
● ├─brandbot.path
● ├─chronyd.service
● ├─crond.service
● ├─cups.path
lines 1-23...skipping...
local bootup script support
[root@station14 ram]# cat -n /etc/rc.local
1 #!/bin/bash
2 # THIS FILE IS ADDED FOR COMPATIBILITY PURPOSES
3 #
4 # It is highly advisable to create own systemd services or udev rules
5 # to run scripts during boot instead of using this file.
6 #
7 # In contrast to previous versions due to parallel execution during boot
8 # this script will NOT be run after all other services.
9 #
10 # Please note that you must run 'chmod +x /etc/rc.d/rc.local' to ensure
11 # that this script will be executed during boot.
12
13 touch /var/lock/subsys/local
[root@station14 ram]# vi /etc/rc.local
1 #!/bin/bash
2 # THIS FILE IS ADDED FOR COMPATIBILITY PURPOSES
3 #
4 # It is highly advisable to create own systemd services or udev rules
5 # to run scripts during boot instead of using this file.
6 #
7 # In contrast to previous versions due to parallel execution during boot
8 # this script will NOT be run after all other services.
9 #
10 # Please note that you must run 'chmod +x /etc/rc.d/rc.local' to ensure
11 # that this script will be executed during boot.
12
13 touch /var/lock/subsys/local
14 rdate -s time.bora.net -- 부팅할 때 time.bora.net과 시간동기화
[root@station14 ram]# chmod +x /etc/rc.d/rc.local
[root@station14 ram]# ll /etc/rc.local
lrwxrwxrwx. 1 root root 13 Apr 8 05:28 /etc/rc.local -> rc.d/rc.local부팅 장애 발생 시킨 후, 장애 해결해보기
@@Physical computer
[root@station14 ~]# cd /var/lib/libvirt/images/
[root@station14 images]# ll
total 6385268
-rw-------. 1 root root 1074135040 Apr 17 10:52 vm1-1.qcow2
-rw-------. 1 root root 1074135040 Apr 17 09:59 vm1-2.qcow2
-rw-------. 1 root root 1074135040 Apr 17 11:11 vm1-3.qcow2
-rw-------. 1 root root 1074135040 Apr 17 11:11 vm1-4.qcow2
-rw-------. 1 qemu qemu 1074135040 Apr 18 14:18 vm1-5.qcow2
-rw-------. 1 qemu qemu 1074135040 Apr 18 14:18 vm1-6.qcow2
-rw-------. 1 qemu qemu 1074921472 Apr 18 14:18 vm1-7.qcow2
-rw-------. 1 qemu qemu 1074135040 Apr 18 14:18 vm1-8.qcow2
-rw-------. 1 qemu qemu 22654550016 Apr 18 14:19 vm1.qcow2
[root@station14 images]# wget http://59.29.224.181/CentOS.iso
--2023-04-18 14:20:02-- http://59.29.224.181/CentOS.iso
Connecting to 59.29.224.181:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 1020264448 (973M) [application/octet-stream]
Saving to: ‘CentOS.iso’
100%[============================================================>] 1,020,264,448 4.28MB/s in 2m 42s
2023-04-18 14:22:43 (6.01 MB/s) - ‘CentOS.iso’ saved [1020264448/1020264448]
@@ Virtual Machine
> 부트로더 손상시키기
dd if=/dev/zero of=/dev/vda bs=64 count=1
study log