Otu esi ejikwa Systemd Ọrụ na nkeji site na iji Systemctl na Linux


Systemctl bụ akụrụngwa sistemụ na-ahụ maka njikwa sistemụ na njikwa ọrụ. Systemd bụ nchịkọta daemons njikwa sistemu, akụrụngwa, na ọba akwụkwọ nke na-arụ ọrụ dị ka nnọchi nke Sistemụ V init daemon. Sistemu na-arụ ọrụ dị ka njikwa etiti yana ikpo okwu nhazi maka UNIX dị ka sistemụ.

Na Linux, Ecosystem System ka etinyere n'ọtụtụ nkesa Linux ọkọlọtọ ma ewezuga ole na ole. Systemd bụ usoro nne na nna nke daemons ndị ọzọ na-emekarị ma ọ bụghị mgbe niile.

Edemede a bu n'obi ịgbanye ọkụ na \Otu esi ejikwa Sistemu na Ọrụ na sistemụ na-arụ ọrụ.

Malite na Systemtd na Systemctl Basics

1. Nke mbụ, lelee ma ọ bụrụ na arụnyere sistemu na sistemụ gị ma ọ bụ na ọ bụghị, gịnịkwa bụ ụdị sistemụ arụnyere ugbu a?

# systemctl --version

systemd 215
+PAM +AUDIT +SELINUX +IMA +SYSVINIT +LIBCRYPTSETUP +GCRYPT +ACL +XZ -SECCOMP -APPARMOR

O doro anya na ihe atụ dị n'elu, na anyị etinyela ụdị 215 sistemu.

2. Lelee ebe etinyere ọnụọgụ abụọ na ọba akwụkwọ nke systemd na systemctl.

# whereis systemd 
systemd: /usr/lib/systemd /etc/systemd /usr/share/systemd /usr/share/man/man1/systemd.1.gz


# whereis systemctl
systemctl: /usr/bin/systemctl /usr/share/man/man1/systemctl.1.gz

3. Lelee ma systemd na-agba ọsọ ma ọ bụ na ọ bụghị.

# ps -eaf | grep [s]ystemd

root         1     0  0 16:27 ?        00:00:00 /usr/lib/systemd/systemd --switched-root --system --deserialize 23
root       444     1  0 16:27 ?        00:00:00 /usr/lib/systemd/systemd-journald
root       469     1  0 16:27 ?        00:00:00 /usr/lib/systemd/systemd-udevd
root       555     1  0 16:27 ?        00:00:00 /usr/lib/systemd/systemd-logind
dbus       556     1  0 16:27 ?        00:00:00 /bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation

Mara: systemd na-agba ọsọ dị ka daemon nne na nna (PID=1). N'iwu dị n'elu ps na (-e) họrọ usoro niile, (-a) họrọ usoro niile ma e wezụga ndị isi nnọkọ na (-f) maka ndepụta usoro zuru ezu (ie -eaf).

Ọzọkwa, rịba ama brackets square dị n'ụkpụrụ dị n'elu yana ihe atụ ndị ọzọ ị ga-eso. Okwu bracket Square bụ akụkụ nke ndakọrịta ụkpụrụ agwa grep.

4. Nyochaa usoro buut sistemu.

# systemd-analyze
Startup finished in 487ms (kernel) + 2.776s (initrd) + 20.229s (userspace) = 23.493s

5. Nyochaa oge ewepụtara usoro ọ bụla na buut.

# systemd-analyze blame

8.565s mariadb.service
7.991s webmin.service
6.095s postfix.service
4.311s httpd.service
3.926s firewalld.service
3.780s kdump.service
3.238s tuned.service
1.712s network.service
1.394s lvm2-monitor.service
1.126s systemd-logind.service
....

6. Nyochaa agbụ dị egwu na buut.

# systemd-analyze critical-chain

The time after the unit is active or started is printed after the "@" character.
The time the unit takes to start is printed after the "+" character.

multi-user.target @20.222s
└─mariadb.service @11.657s +8.565s
  └─network.target @11.168s
    └─network.service @9.456s +1.712s
      └─NetworkManager.service @8.858s +596ms
        └─firewalld.service @4.931s +3.926s
          └─basic.target @4.916s
            └─sockets.target @4.916s
              └─dbus.socket @4.916s
                └─sysinit.target @4.905s
                  └─systemd-update-utmp.service @4.864s +39ms
                    └─auditd.service @4.563s +301ms
                      └─systemd-tmpfiles-setup.service @4.485s +69ms
                        └─rhel-import-state.service @4.342s +142ms
                          └─local-fs.target @4.324s
                            └─boot.mount @4.286s +31ms
                              └─[email \x2duuid-79f594ad\x2da332\x2d4730\x2dbb5f\x2d85d19608096
                                └─dev-disk-by\x2duuid-79f594ad\x2da332\x2d4730\x2dbb5f\x2d85d196080964.device @4

Ihe dị mkpa: Systemctl na-anabata ọrụ (.ọrụ), mount point (.mount), sockets (.socket) na ngwaọrụ (.ngwaọrụ) dị ka nkeji.

7. Depụta nkeji niile dị.

# systemctl list-unit-files

UNIT FILE                                   STATE   
proc-sys-fs-binfmt_misc.automount           static  
dev-hugepages.mount                         static  
dev-mqueue.mount                            static  
proc-sys-fs-binfmt_misc.mount               static  
sys-fs-fuse-connections.mount               static  
sys-kernel-config.mount                     static  
sys-kernel-debug.mount                      static  
tmp.mount                                   disabled
brandbot.path                               disabled
.....

8. Depụta nkeji niile na-agba ọsọ.

# systemctl list-units

UNIT                                        LOAD   ACTIVE SUB       DESCRIPTION
proc-sys-fs-binfmt_misc.automount           loaded active waiting   Arbitrary Executable File Formats File Syste
sys-devices-pc...0-1:0:0:0-block-sr0.device loaded active plugged   VBOX_CD-ROM
sys-devices-pc...:00:03.0-net-enp0s3.device loaded active plugged   PRO/1000 MT Desktop Adapter
sys-devices-pc...00:05.0-sound-card0.device loaded active plugged   82801AA AC'97 Audio Controller
sys-devices-pc...:0:0-block-sda-sda1.device loaded active plugged   VBOX_HARDDISK
sys-devices-pc...:0:0-block-sda-sda2.device loaded active plugged   LVM PV Qzyo3l-qYaL-uRUa-Cjuk-pljo-qKtX-VgBQ8
sys-devices-pc...0-2:0:0:0-block-sda.device loaded active plugged   VBOX_HARDDISK
sys-devices-pl...erial8250-tty-ttyS0.device loaded active plugged   /sys/devices/platform/serial8250/tty/ttyS0
sys-devices-pl...erial8250-tty-ttyS1.device loaded active plugged   /sys/devices/platform/serial8250/tty/ttyS1
sys-devices-pl...erial8250-tty-ttyS2.device loaded active plugged   /sys/devices/platform/serial8250/tty/ttyS2
sys-devices-pl...erial8250-tty-ttyS3.device loaded active plugged   /sys/devices/platform/serial8250/tty/ttyS3
sys-devices-virtual-block-dm\x2d0.device    loaded active plugged   /sys/devices/virtual/block/dm-0
sys-devices-virtual-block-dm\x2d1.device    loaded active plugged   /sys/devices/virtual/block/dm-1
sys-module-configfs.device                  loaded active plugged   /sys/module/configfs
...

9. Depụta nkeji niile dara ada.

# systemctl --failed

UNIT          LOAD   ACTIVE SUB    DESCRIPTION
kdump.service loaded failed failed Crash recovery kernel arming

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.

1 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.

10. Lelee ma ọ bụrụ na agbanyere Unit (cron.service) ma ọ bụ na ọ kwadoghị?.

# systemctl is-enabled crond.service

enabled

11. Lelee ma Unit ma ọ bụ Ọrụ na-agba ọsọ ma ọ bụ na ọ naghị arụ ọrụ?

# systemctl status firewalld.service

firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled)
   Active: active (running) since Tue 2015-04-28 16:27:55 IST; 34min ago
 Main PID: 549 (firewalld)
   CGroup: /system.slice/firewalld.service
           └─549 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid

Apr 28 16:27:51 tecmint systemd[1]: Starting firewalld - dynamic firewall daemon...
Apr 28 16:27:55 tecmint systemd[1]: Started firewalld - dynamic firewall daemon.

Jikwaa ma jikwaa ọrụ Iji Systemctl

12. Depụta ọrụ niile (gụnyere enyere na nkwarụ).

# systemctl list-unit-files --type=service

UNIT FILE                                   STATE   
arp-ethers.service                          disabled
auditd.service                              enabled 
[email                              disabled
blk-availability.service                    disabled
brandbot.service                            static  
collectd.service                            disabled
console-getty.service                       disabled
console-shell.service                       disabled
cpupower.service                            disabled
crond.service                               enabled 
dbus-org.fedoraproject.FirewallD1.service   enabled 
....

13. Kedu ka m ga-esi malite, malitegharịa, kwụsị, bugharịa ma lelee ọnọdụ ọrụ (httpd.service) na Linux.

# systemctl start httpd.service
# systemctl restart httpd.service
# systemctl stop httpd.service
# systemctl reload httpd.service
# systemctl status httpd.service

httpd.service - The Apache HTTP Server
   Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled)
   Active: active (running) since Tue 2015-04-28 17:21:30 IST; 6s ago
  Process: 2876 ExecStop=/bin/kill -WINCH ${MAINPID} (code=exited, status=0/SUCCESS)
 Main PID: 2881 (httpd)
   Status: "Processing requests..."
   CGroup: /system.slice/httpd.service
           ├─2881 /usr/sbin/httpd -DFOREGROUND
           ├─2884 /usr/sbin/httpd -DFOREGROUND
           ├─2885 /usr/sbin/httpd -DFOREGROUND
           ├─2886 /usr/sbin/httpd -DFOREGROUND
           ├─2887 /usr/sbin/httpd -DFOREGROUND
           └─2888 /usr/sbin/httpd -DFOREGROUND

Apr 28 17:21:30 tecmint systemd[1]: Starting The Apache HTTP Server...
Apr 28 17:21:30 tecmint httpd[2881]: AH00558: httpd: Could not reliably determine the server's fully q...ssage
Apr 28 17:21:30 tecmint systemd[1]: Started The Apache HTTP Server.
Hint: Some lines were ellipsized, use -l to show in full.

Mara: Mgbe anyị na-eji iwu dị ka mmalite, malitegharịa, kwụsị ma bugharịa ya na systemctl, anyị agaghị enweta nsonaazụ ọ bụla na ọnụ, naanị iwu ọkwa ga-ebipụta nsonaazụ ahụ.

14. Otu esi arụ ọrụ ma mee ka ma ọ bụ gbanyụọ ọrụ n'oge buut (ọrụ autostart na sistemụ buut).

# systemctl is-active httpd.service
# systemctl enable httpd.service
# systemctl disable httpd.service

15. Otu esi ekpuchi (na-eme ka ọ ghara ịmalite ịmalite) ma ọ bụ wepụ ọrụ (httpd.service).

# systemctl mask httpd.service
ln -s '/dev/null' '/etc/systemd/system/httpd.service'

# systemctl unmask httpd.service
rm '/etc/systemd/system/httpd.service'

16. Otu esi egbu ọrụ site na iji systemctl iwu.

# systemctl kill httpd
# systemctl status httpd

httpd.service - The Apache HTTP Server
   Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled)
   Active: failed (Result: exit-code) since Tue 2015-04-28 18:01:42 IST; 28min ago
 Main PID: 2881 (code=exited, status=0/SUCCESS)
   Status: "Total requests: 0; Current requests/sec: 0; Current traffic:   0 B/sec"

Apr 28 17:37:29 tecmint systemd[1]: httpd.service: Got notification message from PID 2881, but recepti...bled.
Apr 28 17:37:29 tecmint systemd[1]: httpd.service: Got notification message from PID 2881, but recepti...bled.
Apr 28 17:37:39 tecmint systemd[1]: httpd.service: Got notification message from PID 2881, but recepti...bled.
Apr 28 17:37:39 tecmint systemd[1]: httpd.service: Got notification message from PID 2881, but recepti...bled.
Apr 28 17:37:49 tecmint systemd[1]: httpd.service: Got notification message from PID 2881, but recepti...bled.
Apr 28 17:37:49 tecmint systemd[1]: httpd.service: Got notification message from PID 2881, but recepti...bled.
Apr 28 17:37:59 tecmint systemd[1]: httpd.service: Got notification message from PID 2881, but recepti...bled.
Apr 28 17:37:59 tecmint systemd[1]: httpd.service: Got notification message from PID 2881, but recepti...bled.
Apr 28 18:01:42 tecmint systemd[1]: httpd.service: control process exited, code=exited status=226
Apr 28 18:01:42 tecmint systemd[1]: Unit httpd.service entered failed state.
Hint: Some lines were ellipsized, use -l to show in full.

Jikwaa ma jikwaa ebe ugwu site na iji Systemctl

17. Depụta ihe niile usoro ugwu ugwu.

# systemctl list-unit-files --type=mount

UNIT FILE                     STATE   
dev-hugepages.mount           static  
dev-mqueue.mount              static  
proc-sys-fs-binfmt_misc.mount static  
sys-fs-fuse-connections.mount static  
sys-kernel-config.mount       static  
sys-kernel-debug.mount        static  
tmp.mount                     disabled

18. Kedu ka m ga-esi na-ebuli, bulite, remount, reload system mount point na-elele ọnọdụ nke ugwu ihe na usoro?

# systemctl start tmp.mount
# systemctl stop tmp.mount
# systemctl restart tmp.mount
# systemctl reload tmp.mount
# systemctl status tmp.mount

tmp.mount - Temporary Directory
   Loaded: loaded (/usr/lib/systemd/system/tmp.mount; disabled)
   Active: active (mounted) since Tue 2015-04-28 17:46:06 IST; 2min 48s ago
    Where: /tmp
     What: tmpfs
     Docs: man:hier(7)
           http://www.freedesktop.org/wiki/Software/systemd/APIFileSystems
  Process: 3908 ExecMount=/bin/mount tmpfs /tmp -t tmpfs -o mode=1777,strictatime (code=exited, status=0/SUCCESS)

Apr 28 17:46:06 tecmint systemd[1]: Mounting Temporary Directory...
Apr 28 17:46:06 tecmint systemd[1]: tmp.mount: Directory /tmp to mount over is not empty, mounting anyway.
Apr 28 17:46:06 tecmint systemd[1]: Mounted Temporary Directory.

19. Otu esi arụ ọrụ, mee ma ọ bụ gbanyụọ ebe mgbago n'oge buut (na-ebugo akpaaka na boot system).

# systemctl is-active tmp.mount
# systemctl enable tmp.mount
# systemctl disable  tmp.mount

20. Otu esi ekpuchi (na-eme ka ọ ghara ịmalite ịmalite) ma ọ bụ kpughee ebe ugwu na Linux.

# systemctl mask tmp.mount

ln -s '/dev/null' '/etc/systemd/system/tmp.mount'

# systemctl unmask tmp.mount

rm '/etc/systemd/system/tmp.mount'

Jikwaa ma jikwaa Sockets site na iji Systemctl

21. Depụta oghere sistemụ niile dị.

# systemctl list-unit-files --type=socket

UNIT FILE                    STATE   
dbus.socket                  static  
dm-event.socket              enabled 
lvm2-lvmetad.socket          enabled 
rsyncd.socket                disabled
sshd.socket                  disabled
syslog.socket                static  
systemd-initctl.socket       static  
systemd-journald.socket      static  
systemd-shutdownd.socket     static  
systemd-udevd-control.socket static  
systemd-udevd-kernel.socket  static  

11 unit files listed.

22. Kedu ka m ga-esi malite, malitegharịa, kwụsị, bugharịa ma lelee ọnọdụ nke oghere (ihe atụ: cups.socket) na Linux.

# systemctl start cups.socket
# systemctl restart cups.socket
# systemctl stop cups.socket
# systemctl reload cups.socket
# systemctl status cups.socket

cups.socket - CUPS Printing Service Sockets
   Loaded: loaded (/usr/lib/systemd/system/cups.socket; enabled)
   Active: active (listening) since Tue 2015-04-28 18:10:59 IST; 8s ago
   Listen: /var/run/cups/cups.sock (Stream)

Apr 28 18:10:59 tecmint systemd[1]: Starting CUPS Printing Service Sockets.
Apr 28 18:10:59 tecmint systemd[1]: Listening on CUPS Printing Service Sockets.

23. Otu esi arụ ọrụ oghere ma mee ma ọ bụ gbanyụọ n'oge buut (autostart socket na system boot).

# systemctl is-active cups.socket
# systemctl enable cups.socket
# systemctl disable cups.socket

24. Otu esi ekpuchi (na-eme ka ọ ghara ịmalite ịmalite) ma ọ bụ wepụ ihe mkpuchi (cup.socket).

# systemctl mask cups.socket
ln -s '/dev/null' '/etc/systemd/system/cups.socket'

# systemctl unmask cups.socket
rm '/etc/systemd/system/cups.socket'