이번 게시물에서는 Centos7 / RHEL7 에 본격 적용이 된 Systemd 에 대해서 알아보고 다양한 활용 예시에 대해서 알아보고자 한다.
Systemd는 Centos6 버전까지 기반이였던 SystemV init을 대체하는 System 통합제어 프로세스로서 PID 1로 기동된다.
SystemV Init 의 역활은 전통적 Unix 와 같이 Kernel Level에서 작동하는 시스템 최상위 초기자로서 하위에 생성되는 모든 Process들 통제하고 관리한다.
하지만 Systemd는 단순 시스템 초기자의 역활만이 아닌 시스템의 통합 로그 관리자는 물론 서비스, HW, Timezone 등 다양한 시스템 영역을 관여하고 있다.
Systemd 에 대한 보다 자세한 사항은 아래 Sysemd 개발 Site을 참고하자 - https://www.freedesktop.org/wiki/Software/systemd/
1. 시스템에 설치되어있는 전체 서비스 상태 확인하기
[root@centos7 ~]# [root@centos7 ~]# systemctl -at service UNIT LOAD ACTIVE SUB DESCRIPTION abrt-ccpp.service loaded active exited Install ABRT coredump hook abrt-oops.service loaded active running ABRT kernel log watcher abrt-vmcore.service loaded inactive dead Harvest vmcores for ABRT abrt-xorg.service loaded active running ABRT Xorg log watcher abrtd.service loaded active running ABRT Automated Bug Reporting Tool accounts-daemon.service loaded active running Accounts Service alsa-restore.service loaded inactive dead Restore Sound Card State alsa-state.service loaded active running Manage Sound Card State (restore and stor alsa-store.service loaded inactive dead Store Sound Card State ● apparmor.service not-found inactive dead apparmor.service atd.service loaded active running Job spooling tools auditd.service loaded active running Security Auditing Service auth-rpcgss-module.service loaded inactive dead Kernel Module supporting RPCSEC_GSS avahi-daemon.service loaded active running Avahi mDNS/DNS-SD Stack blk-availability.service loaded active exited Availability of block devices bluetooth.service loaded active running Bluetooth service brandbot.service loaded inactive dead Flexible Branding Service chronyd.service loaded active running NTP client/server colord.service loaded active running Manage, Install and Generate Color Profil cpupower.service loaded inactive dead Configure CPU power related settings crond.service loaded active running Command Scheduler
※ 시스템에 설치되어있는 전체 Service 파일에 대한 수동 조회
[root@centos7 ~]# [root@centos7 ~]# find /usr/lib/systemd/system/ -name \*.service /usr/lib/systemd/system/tog-pegasus.service /usr/lib/systemd/system/vboxadd.service /usr/lib/systemd/system/systemd-halt.service /usr/lib/systemd/system/autovt@.service /usr/lib/systemd/system/systemd-kexec.service /usr/lib/systemd/system/basic.target.wants/rhel-autorelabel-mark.service /usr/lib/systemd/system/basic.target.wants/rhel-autorelabel.service /usr/lib/systemd/system/basic.target.wants/rhel-configure.service /usr/lib/systemd/system/basic.target.wants/rhel-dmesg.service /usr/lib/systemd/system/basic.target.wants/rhel-loadmodules.service /usr/lib/systemd/system/basic.target.wants/alsa-restore.service /usr/lib/systemd/system/basic.target.wants/alsa-state.service /usr/lib/systemd/system/runlevel4.target.wants/systemd-update-utmp-runlevel.service /usr/lib/systemd/system/console-getty.service /usr/lib/systemd/system/console-shell.service /usr/lib/systemd/system/runlevel5.target.wants/systemd-update-utmp-runlevel.service /usr/lib/systemd/system/systemd-udevd.service /usr/lib/systemd/system/dbus-org.freedesktop.hostname1.service /usr/lib/systemd/system/dbus-org.freedesktop.locale1.service /usr/lib/systemd/system/dbus-org.freedesktop.login1.service /usr/lib/systemd/system/dbus-org.freedesktop.machine1.service /usr/lib/systemd/system/dbus.service /usr/lib/systemd/system/dbus-org.freedesktop.timedate1.service /usr/lib/systemd/system/debug-shell.service /usr/lib/systemd/system/serial-getty@.service /usr/lib/systemd/system/emergency.service /usr/lib/systemd/system/messagebus.service |
2. 현재 활성화 되어있는 Service 확인하기
[root@centos7 ~]# [root@centos7 ~]# systemctl -t service --state=active UNIT LOAD ACTIVE SUB DESCRIPTION abrt-ccpp.service loaded active exited Install ABRT coredump hook abrt-oops.service loaded active running ABRT kernel log watcher abrt-xorg.service loaded active running ABRT Xorg log watcher abrtd.service loaded active running ABRT Automated Bug Reporting Tool accounts-daemon.service loaded active running Accounts Service alsa-state.service loaded active running Manage Sound Card State (restore and store) atd.service loaded active running Job spooling tools auditd.service loaded active running Security Auditing Service avahi-daemon.service loaded active running Avahi mDNS/DNS-SD Stack blk-availability.service loaded active exited Availability of block devices bluetooth.service loaded active running Bluetooth service chronyd.service loaded active running NTP client/server colord.service loaded active running Manage, Install and Generate Color Profiles crond.service loaded active running Command Scheduler cups.service loaded active running CUPS Printing Service dbus.service loaded active running D-Bus System Message Bus firewalld.service loaded active running firewalld - dynamic firewall daemon gdm.service loaded active running GNOME Display Manager gssproxy.service loaded active running GSSAPI Proxy Daemon httpd.service loaded active running The Apache HTTP Server irqbalance.service loaded active running irqbalance daemon iscsi-shutdown.service loaded active exited Logout off all iSCSI sessions on shutdown kdump.service loaded active exited Crash recovery kernel arming kmod-static-nodes.service loaded active exited Create list of required static device nodes fo ksm.service loaded active exited Kernel Samepage Merging loaded active running Command Scheduler
[root@centos7 ~]# [root@centos7 ~]# systemctl list-units --type service UNIT LOAD ACTIVE SUB DESCRIPTION abrt-ccpp.service loaded active exited Install ABRT coredump hook abrt-oops.service loaded active running ABRT kernel log watcher abrt-xorg.service loaded active running ABRT Xorg log watcher abrtd.service loaded active running ABRT Automated Bug Reporting Tool accounts-daemon.service loaded active running Accounts Service alsa-state.service loaded active running Manage Sound Card State (restore and store) atd.service loaded active running Job spooling tools auditd.service loaded active running Security Auditing Service avahi-daemon.service loaded active running Avahi mDNS/DNS-SD Stack blk-availability.service loaded active exited Availability of block devices bluetooth.service loaded active running Bluetooth service chronyd.service loaded active running NTP client/server colord.service loaded active running Manage, Install and Generate Color Profiles crond.service loaded active running Command Scheduler cups.service loaded active running CUPS Printing Service dbus.service loaded active running D-Bus System Message Bus firewalld.service loaded active running firewalld - dynamic firewall daemon
※ Service Link 파일에 대한 트리 직접확인
[root@centos7 ~]# [root@centos7 ~]# find /etc/systemd/system/ -type l -name \*.service /etc/systemd/system/getty.target.wants/getty@tty1.service /etc/systemd/system/multi-user.target.wants/abrtd.service /etc/systemd/system/multi-user.target.wants/abrt-oops.service /etc/systemd/system/multi-user.target.wants/crond.service /etc/systemd/system/multi-user.target.wants/kdump.service /etc/systemd/system/multi-user.target.wants/abrt-vmcore.service /etc/systemd/system/multi-user.target.wants/sysstat.service /etc/systemd/system/multi-user.target.wants/avahi-daemon.service /etc/systemd/system/multi-user.target.wants/libstoragemgmt.service /etc/systemd/system/multi-user.target.wants/abrt-ccpp.service /etc/systemd/system/multi-user.target.wants/abrt-xorg.service /etc/systemd/system/multi-user.target.wants/rpcbind.service /etc/systemd/system/multi-user.target.wants/mdmonitor.service /etc/systemd/system/multi-user.target.wants/rsyslog.service /etc/systemd/system/multi-user.target.wants/NetworkManager.service /etc/systemd/system/multi-user.target.wants/auditd.service /etc/systemd/system/multi-user.target.wants/postfix.service /etc/systemd/system/multi-user.target.wants/irqbalance.service /etc/systemd/system/multi-user.target.wants/smartd.service /etc/systemd/system/multi-user.target.wants/tuned.service |
3. 특정 서비스 시작/중지/상태 확인하기
[root@centos7 ~]# [root@centos7 ~]# systemctl stop httpd.service [root@centos7 ~]# [root@centos7 ~]# systemctl start httpd.service [root@centos7 ~]# [root@centos7 ~]# systemctl status httpd.service ● httpd.service - The Apache HTTP Server Loaded: loaded (/etc/systemd/system/httpd.service; enabled; vendor preset: disabled) Active: active (running) since 금 2016-02-12 15:15:55 KST; 7s ago Docs: man:httpd(8) man:apachectl(8) Process: 28338 ExecStopPost=/usr/bin/kdestroy -A (code=exited, status=0/SUCCESS) Process: 28288 ExecStop=/bin/kill -WINCH ${MAINPID} (code=exited, status=0/SUCCESS) Process: 28406 ExecStartPre=/usr/libexec/ipa/ipa-httpd-kdcproxy (code=exited, status=0/SUCCESS) Main PID: 28456 (httpd) Status: "Processing requests..." CGroup: /system.slice/httpd.service ├─28456 /usr/sbin/httpd -DFOREGROUND ├─28458 /usr/libexec/nss_pcache 524292 off /etc/httpd/alias ├─28460 /usr/sbin/httpd -DFOREGROUND ├─28461 /usr/sbin/httpd -DFOREGROUND ├─28462 /usr/sbin/httpd -DFOREGROUND ├─28463 /usr/sbin/httpd -DFOREGROUND ├─28464 /usr/sbin/httpd -DFOREGROUND └─28465 /usr/sbin/httpd -DFOREGROUND
2월 12 15:15:52 centos7 systemd[1]: Starting The Apache HTTP Server... 2월 12 15:15:54 centos7 ipa-httpd-kdcproxy[28406]: ipa : WARNING Unable to connect to dirsrv: Timeout exceeded 2월 12 15:15:54 centos7 ipa-httpd-kdcproxy[28406]: ipa : WARNING Disabling KDC proxy 2월 12 15:15:54 centos7 httpd[28456]: AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using fe80::a00:27ff:fec3:c843. Set the 'ServerName' directive globally to suppress this message 2월 12 15:15:55 centos7 systemd[1]: Started The Apache HTTP Server. [root@centos7 ~]# [root@centos7 ~]# |
4. 부팅시 특정서비스에 대한 활성/비활성 등록
[root@centos7 ~]# [root@centos7 ~]# systemctl disable httpd.service Removed symlink /etc/systemd/system/multi-user.target.wants/httpd.service. [root@centos7 ~]# [root@centos7 ~]# [root@centos7 ~]# systemctl enable httpd.service Created symlink from /etc/systemd/system/multi-user.target.wants/httpd.service to /etc/systemd/system/httpd.service. [root@centos7 ~]# [root@centos7 ~]# |
5. 특정 서비스에 대한 활성화 여부 확인하기
[root@centos7 ~]# [root@centos7 ~]# systemctl is-enabled httpd.service enabled [root@centos7 ~]# [root@centos7 ~]# |
6. 시스템 기본 Run Level 및 현재 Booting Run Level 확인
[root@centos7 ~]# [root@centos7 ~]# systemctl get-default graphical.target [root@centos7 ~]# [root@centos7 ~]# who -r run-level 5 2016-02-12 13:04 [root@centos7 ~]# [root@centos7 ~]# |
7. 시스템 부팅시 기본 Run Level 변경 설정
[root@centos7 ~]# [root@centos7 ~]# cat /etc/inittab | grep runlevel # systemd uses 'targets' instead of runlevels. By default, there are two main targets: # multi-user.target: analogous to runlevel 3 # graphical.target: analogous to runlevel 5 [root@centos7 ~]# [root@centos7 ~]# [root@centos7 ~]# systemctl set-default multi-user.target Removed symlink /etc/systemd/system/default.target. Created symlink from /etc/systemd/system/default.target to /usr/lib/systemd/system/multi-user.target. [root@centos7 ~]#
[root@centos7 ~]# [root@centos7 ~]# systemctl set-default graphical.target Removed symlink /etc/systemd/system/default.target. Created symlink from /etc/systemd/system/default.target to /usr/lib/systemd/system/graphical.target. [root@centos7 ~]# [root@centos7 ~]# |
8. 시스템 Run Level 즉시 변경
(※ 주의 : 현재 Run Level에 종속적 및 실행중인 Service 중단 및 영향 발생)
[root@centos7 ~]# [root@centos7 ~]# systemctl isolate multi-user.target [root@centos7 ~]# [root@centos7 ~]# who -r run-level 3 2016-02-12 15:32 last=5 [root@centos7 ~]# [root@centos7 ~]#
※ systemctl isolate runlevel3.target 대체가능
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9. 시스템 주요 Log 확인
[root@centos7 ~]# [root@centos7 ~]# [root@centos7 ~]# journalctl -a -m -- Logs begin at 금 2016-02-12 13:03:41 KST, end at 금 2016-02-12 15:40:02 KST. -- 2월 12 13:03:41 centos7 systemd-journal[93]: Runtime journal is using 8.0M (max allowed 92.0M, trying to leave 13 2월 12 13:03:41 centos7 systemd-journal[93]: Runtime journal is using 8.0M (max allowed 92.0M, trying to leave 13 2월 12 13:03:41 centos7 kernel: Initializing cgroup subsys cpuset 2월 12 13:03:41 centos7 kernel: Initializing cgroup subsys cpu 2월 12 13:03:41 centos7 kernel: Initializing cgroup subsys cpuacct 2월 12 13:03:41 centos7 kernel: Linux version 3.10.0-123.el7.x86_64 (builder@kbuilder.dev.centos.org) (gcc versio 2월 12 13:03:41 centos7 kernel: Command line: BOOT_IMAGE=/vmlinuz-3.10.0-123.el7.x86_64 root=/dev/mapper/centos-r 2월 12 13:03:41 centos7 kernel: e820: BIOS-provided physical RAM map: 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x0000000000100000-0x000000007ffeffff] usable 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x000000007fff0000-0x000000007fffffff] ACPI data 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved 2월 12 13:03:41 centos7 kernel: NX (Execute Disable) protection: active 2월 12 13:03:41 centos7 kernel: SMBIOS 2.5 present.
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10. 특정 서비스 Log 확인 ( -f 옵션 추가시 지속 확인 : tail -f 와 동일)
[root@centos7 ~]# [root@centos7 ~]# journalctl -u httpd.service -- Logs begin at 금 2016-02-12 13:03:41 KST. -- 2월 12 13:04:01 centos7 ipa-httpd-kdcproxy[1596]: ipa : WARNING Disabling KDC proxy 2월 12 13:04:01 centos7 httpd[3074]: AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using fe80::a00:27ff:fec3:c843. Set the 'ServerName' directive globally to suppress this message 2월 12 13:04:01 centos7 systemd[1]: Started The Apache HTTP Server. 2월 12 15:15:46 centos7 systemd[1]: Stopping The Apache HTTP Server... 2월 12 15:15:47 centos7 systemd[1]: Stopped The Apache HTTP Server. 2월 12 15:15:52 centos7 systemd[1]: Starting The Apache HTTP Server... 2월 12 15:15:54 centos7 ipa-httpd-kdcproxy[28406]: ipa : WARNING Unable to connect to dirsrv: Timeout exceeded 2월 12 15:15:54 centos7 ipa-httpd-kdcproxy[28406]: ipa : WARNING Disabling KDC proxy 2월 12 15:15:54 centos7 httpd[28456]: AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using fe80::a00:27ff:fec3:c843. Set the 'ServerName' directive globally to suppress this message 2월 12 15:15:55 centos7 systemd[1]: Started The Apache HTTP Server.
[root@centos7 ~]# [root@centos7 ~]# [root@centos7 ~]# journalctl -u crond.service -- Logs begin at 금 2016-02-12 13:03:41 KST, end at 금 2016-02-12 15:58:01 KST. -- 2월 12 13:03:53 centos7 systemd[1]: Started Command Scheduler. 2월 12 13:03:53 centos7 systemd[1]: Starting Command Scheduler... 2월 12 13:03:53 centos7 crond[1645]: (CRON) INFO (RANDOM_DELAY will be scaled with factor 52% if used.) 2월 12 13:03:53 centos7 crond[1645]: (CRON) INFO (running with inotify support) [root@centos7 ~]# |
11. 특정 PID 에 대한 Log 확인
[root@centos7 ~]# [root@centos7 ~]# ps -ef | grep cron root 1645 1 0 13:03 ? 00:00:00 /usr/sbin/crond -n root 3542 14535 0 15:59 pts/0 00:00:00 grep --color=auto cron [root@centos7 ~]# [root@centos7 ~]# [root@centos7 ~]# journalctl _PID=1645 -- Logs begin at 금 2016-02-12 13:03:41 KST, end at 금 2016-02-12 15:58:01 KST. -- 2월 12 13:03:53 centos7 crond[1645]: (CRON) INFO (RANDOM_DELAY will be scaled with factor 52% if used.) 2월 12 13:03:53 centos7 crond[1645]: (CRON) INFO (running with inotify support) [root@centos7 ~]# [root@centos7 ~]# [root@centos7 ~]# |
12. Kernel Messages (dmesg) 확인
[root@centos7 ~]# [root@centos7 ~]# journalctl -k -- Logs begin at 금 2016-02-12 13:03:41 KST, end at 금 2016-02-12 15:50:01 KST. -- 2월 12 13:03:41 centos7 kernel: Initializing cgroup subsys cpuset 2월 12 13:03:41 centos7 kernel: Initializing cgroup subsys cpu 2월 12 13:03:41 centos7 kernel: Initializing cgroup subsys cpuacct 2월 12 13:03:41 centos7 kernel: Linux version 3.10.0-123.el7.x86_64 (builder@kbuilder.dev.centos.org) (gcc versio 2월 12 13:03:41 centos7 kernel: Command line: BOOT_IMAGE=/vmlinuz-3.10.0-123.el7.x86_64 root=/dev/mapper/centos-r 2월 12 13:03:41 centos7 kernel: e820: BIOS-provided physical RAM map: 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x0000000000100000-0x000000007ffeffff] usable 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x000000007fff0000-0x000000007fffffff] ACPI data 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved 2월 12 13:03:41 centos7 kernel: NX (Execute Disable) protection: active
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13. 로그 유형별 조회하기 (debug, info, err)
[root@centos7 ~]# [root@centos7 ~]# journalctl -p err -- Logs begin at 금 2016-02-12 13:03:41 KST, end at 토 2016-02-13 18:10:01 KST. -- 2월 12 13:03:41 centos7 kernel: Detected CPU family 6 model 69 2월 12 13:03:41 centos7 kernel: Warning: Intel CPU model - this hardware has not undergone upstream testing. Plea 2월 12 13:03:41 centos7 kernel: tsc: Fast TSC calibration failed 2월 12 13:03:45 centos7 kernel: piix4_smbus 0000:00:07.0: SMBus base address uninitialized - upgrade BIOS or use 2월 12 13:05:23 centos7 gdm-launch-environment][2779]: pam_systemd(gdm-launch-environment:session): Failed to rel 2월 12 13:05:42 centos7 gdm-password][4116]: pam_unix(gdm-password:auth): conversation failed 2월 12 13:05:42 centos7 gdm-password][4116]: pam_unix(gdm-password:auth): auth could not identify password for [h 2월 12 13:05:49 centos7 gdm-password][4206]: pam_unix(gdm-password:auth): conversation failed 2월 12 13:05:49 centos7 gdm-password][4206]: pam_unix(gdm-password:auth): auth could not identify password for [h 2월 12 13:05:51 centos7 pulseaudio[4475]: [pulseaudio] pid.c: Daemon already running. 2월 12 13:05:58 centos7 gdm-password][4715]: pam_unix(gdm-password:auth): conversation failed 2월 12 13:05:58 centos7 gdm-password][4715]: pam_unix(gdm-password:auth): auth could not identify password for [h 2월 12 15:36:13 centos7 pulseaudio[32753]: [pulseaudio] pid.c: Daemon already running. 2월 12 15:37:41 centos7 mate-session[550]: Gtk-CRITICAL: gtk_image_set_from_icon_name: assertion 'GTK_IS_IMAGE (i 2월 12 15:37:46 centos7 pulseaudio[1455]: [pulseaudio] pid.c: Daemon already running. 2월 12 15:38:12 centos7 gdm-password][1683]: pam_unix(gdm-password:auth): conversation failed 2월 12 15:38:12 centos7 gdm-password][1683]: pam_unix(gdm-password:auth): auth could not identify password for [r 2월 12 16:03:28 centos7 gdm-launch-environment][1374]: pam_systemd(gdm-launch-environment:session): Failed to rel [root@centos7 ~]# [root@centos7 ~]# |
14. 일자기준 로그 조회
[root@centos7 ~]# [root@centos7 ~]# journalctl --since=today -- Logs begin at 금 2016-02-12 13:03:41 KST, end at 토 2016-02-13 18:04:13 KST. -- 2월 13 17:45:24 centos7 systemd[1]: Time has been changed 2월 13 17:45:24 centos7 NetworkManager[1062]: <info> (enp0s3): link disconnected (calling deferred action) 2월 13 17:45:24 centos7 NetworkManager[1062]: <info> (enp0s3): device state change: activated -> unavailable (re 2월 13 17:45:24 centos7 avahi-daemon[868]: Withdrawing address record for fe80::a00:27ff:fec3:c843 on enp0s3. 2월 13 17:45:24 centos7 avahi-daemon[868]: Withdrawing address record for 192.168.137.10 on enp0s3. 2월 13 17:45:24 centos7 avahi-daemon[868]: Leaving mDNS multicast group on interface enp0s3.IPv4 with address 192 2월 13 17:45:24 centos7 avahi-daemon[868]: Interface enp0s3.IPv4 no longer relevant for mDNS. 2월 13 17:45:24 centos7 NetworkManager[1062]: <info> NetworkManager state is now CONNECTED_LOCAL 2월 13 17:45:24 centos7 NetworkManager[1062]: <info> NetworkManager state is now DISCONNECTED 2월 13 17:45:24 centos7 dbus[854]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' 2월 13 17:45:24 centos7 dbus-daemon[854]: dbus[854]: [system] Activating via systemd: service name='org.freedeskt 2월 13 17:45:24 centos7 systemd[1]: Starting Network Manager Script Dispatcher Service... 2월 13 17:45:24 centos7 dbus[854]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher' 2월 13 17:45:24 centos7 dbus-daemon[854]: dbus[854]: [system] Successfully activated service 'org.freedesktop.nm_ 2월 13 17:45:24 centos7 systemd[1]: Started Network Manager Script Dispatcher Service. 2월 13 17:45:24 centos7 nm-dispatcher[11077]: Dispatching action 'down' for enp0s3 2월 13 17:45:24 centos7 systemd[1]: Unit named.service cannot be reloaded because it is inactive. 2월 13 17:45:24 centos7 systemd[1]: Unit named-chroot.service cannot be reloaded because it is inactive. 2월 13 17:45:24 centos7 chronyd[890]: Forward time jump detected! 2월 13 17:45:24 centos7 chronyd[890]: Can't synchronise: no selectable sources 2월 13 17:45:24 centos7 chronyd[890]: Source 114.207.245.166 offline 2월 13 17:45:24 centos7 chronyd[890]: Source 106.247.248.106 offline
[root@centos7 ~]# [root@centos7 ~]# journalctl --since=2016-02-12 -- Logs begin at 금 2016-02-12 13:03:41 KST, end at 토 2016-02-13 18:04:13 KST. -- 2월 12 13:03:41 centos7 systemd-journal[93]: Runtime journal is using 8.0M (max allowed 92.0M, trying to leave 13 2월 12 13:03:41 centos7 systemd-journal[93]: Runtime journal is using 8.0M (max allowed 92.0M, trying to leave 13 2월 12 13:03:41 centos7 kernel: Initializing cgroup subsys cpuset 2월 12 13:03:41 centos7 kernel: Initializing cgroup subsys cpu 2월 12 13:03:41 centos7 kernel: Initializing cgroup subsys cpuacct 2월 12 13:03:41 centos7 kernel: Linux version 3.10.0-123.el7.x86_64 (builder@kbuilder.dev.centos.org) (gcc versio 2월 12 13:03:41 centos7 kernel: Command line: BOOT_IMAGE=/vmlinuz-3.10.0-123.el7.x86_64 root=/dev/mapper/centos-r 2월 12 13:03:41 centos7 kernel: e820: BIOS-provided physical RAM map: 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x0000000000100000-0x000000007ffeffff] usable 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x000000007fff0000-0x000000007fffffff] ACPI data 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved 2월 12 13:03:41 centos7 kernel: NX (Execute Disable) protection: active 2월 12 13:03:41 centos7 kernel: SMBIOS 2.5 present.
[root@centos7 ~]# [root@centos7 ~]# journalctl --since=2016-02-12 --until=2016-02-13 -- Logs begin at 금 2016-02-12 13:03:41 KST, end at 토 2016-02-13 18:04:13 KST. -- 2월 12 13:03:41 centos7 systemd-journal[93]: Runtime journal is using 8.0M (max allowed 92.0M, trying to leave 13 2월 12 13:03:41 centos7 systemd-journal[93]: Runtime journal is using 8.0M (max allowed 92.0M, trying to leave 13 2월 12 13:03:41 centos7 kernel: Initializing cgroup subsys cpuset 2월 12 13:03:41 centos7 kernel: Initializing cgroup subsys cpu 2월 12 13:03:41 centos7 kernel: Initializing cgroup subsys cpuacct 2월 12 13:03:41 centos7 kernel: Linux version 3.10.0-123.el7.x86_64 (builder@kbuilder.dev.centos.org) (gcc versio 2월 12 13:03:41 centos7 kernel: Command line: BOOT_IMAGE=/vmlinuz-3.10.0-123.el7.x86_64 root=/dev/mapper/centos-r 2월 12 13:03:41 centos7 kernel: e820: BIOS-provided physical RAM map: 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x0000000000100000-0x000000007ffeffff] usable 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x000000007fff0000-0x000000007fffffff] ACPI data 2월 12 13:03:41 centos7 kernel: BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved 2월 12 13:03:41 centos7 kernel: NX (Execute Disable) protection: active 2월 12 13:03:41 centos7 kernel: SMBIOS 2.5 present. 2월 12 13:03:41 centos7 kernel: DMI: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 2월 12 13:03:41 centos7 kernel: e820: update [mem 0x00000000-0x00000fff] usable ==
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15. 시스템 서비스 전체 또는 특성 서비스에 대한 종속성 Tree 확인
[root@centos7 ~]# [root@centos7 ~]# 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
... 중략
[root@centos7 ~]# [root@centos7 ~]# systemctl list-dependencies multi-user.target multi-user.target ● ├─abrt-ccpp.service ● ├─abrt-oops.service ● ├─abrt-vmcore.service ● ├─abrt-xorg.service ● ├─abrtd.service ● ├─atd.service ● ├─auditd.service ● ├─avahi-daemon.service ● ├─brandbot.path ● ├─chronyd.service ● ├─crond.service ● ├─cups.path ● ├─cups.service ● ├─dbus.service ● ├─httpd.service
... 중략
[root@centos7 ~]# [root@centos7 ~]# systemctl list-dependencies httpd.service httpd.service ● ├─-.mount ● ├─system.slice ● └─basic.target ● ├─alsa-restore.service ● ├─alsa-state.service ● ├─firewalld.service ● ├─microcode.service ● ├─rhel-autorelabel-mark.service ● ├─rhel-autorelabel.service ● ├─rhel-configure.service ● ├─rhel-dmesg.service ● ├─rhel-loadmodules.service ● ├─paths.target ● ├─slices.target ● │ ├─-.slice ● │ └─system.slice ● ├─sockets.target ● │ ├─avahi-daemon.socket ● │ ├─cups.socket
... 중략
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※ 참고 - Systemd VS SysVinit (http://linoxide.com/linux-command/systemd-vs-sysvinit-cheatsheet/)