【CentOS 7筆記47】，systemd系統服務管理#

時間 2019-12-09

標籤 CentOS 7筆記47 systemd 系統服務管理欄目 CentOS 简体版

原文原文鏈接

shallow丿ovenode

systemd

systemctl list-units --all --type=service
幾個經常使用的服務相關的命令
systemctl enable crond.service #讓服務開機啓動
systemctl disable crond #不讓開機啓動
systemctl status crond #查看狀態
systemctl stop crond #中止服務
systemctl start crond #啓動服務
systemctl restart crond #重啓服務
systemctl is-enabled crond #檢查服務是否開機啓動

[root@localhost ~]# systemctl list-unit-files
	UNIT FILE                                   STATE   
	proc-sys-fs-binfmt_misc.automount           static  
	dev-hugepages.mount                         static  
	dev-mqueue.mount                            static  
	proc-fs-nfsd.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
	var-lib-nfs-rpc_pipefs.mount                static  
	brandbot.path                               disabled
	systemd-ask-password-console.path           static  
	systemd-ask-password-plymouth.path          static  
	systemd-ask-password-wall.path              static  
	session-1.scope                             static  
	session-2.scope                             static  
	session-26.scope                            static  

	lines 1-18

[root@localhost ~]# systemctl list-units --all --type=service
	  UNIT                                 LOAD      ACTIVE   SUB     DESCRIPTION
	  auditd.service                       loaded    active   running Security Auditing Service
	  auth-rpcgss-module.service           loaded    inactive dead    Kernel Module supporting RPCSEC_G
	  avahi-daemon.service                 loaded    active   running Avahi mDNS/DNS-SD Stack
	  brandbot.service                     loaded    inactive dead    Flexible Branding Service
	  cpupower.service                     loaded    inactive dead    Configure CPU power related setti
	  crond.service                        loaded    active   running Command Scheduler
	  dbus.service                         loaded    active   running D-Bus System Message Bus
	● display-manager.service              not-found inactive dead    display-manager.service
	  dm-event.service                     loaded    inactive dead    Device-mapper event daemon
	  dracut-shutdown.service              loaded    inactive dead    Restore /run/initramfs
	  ebtables.service                     loaded    inactive dead    Ethernet Bridge Filtering tables
	  emergency.service                    loaded    inactive dead    Emergency Shell
	● exim.service                         not-found inactive dead    exim.service
	  firewalld.service                    loaded    active   running firewalld - dynamic firewall daem
	  getty@tty1.service                   loaded    active   running Getty on tty1
	  gssproxy.service                     loaded    active   running GSSAPI Proxy Daemon
	  ip6tables.service                    loaded    inactive dead    IPv6 firewall with ip6tables

	lines 1-18

不加--allshell

[root@localhost ~]# systemctl list-units --type=service
	  UNIT                                  LOAD   ACTIVE SUB     DESCRIPTION
	  auditd.service                        loaded active running Security Auditing Service
	  avahi-daemon.service                  loaded active running Avahi mDNS/DNS-SD Stack
	  crond.service                         loaded active running Command Scheduler
	  dbus.service                          loaded active running D-Bus System Message Bus
	  firewalld.service                     loaded active running firewalld - dynamic firewall daemon
	  getty@tty1.service                    loaded active running Getty on tty1
	  gssproxy.service                      loaded active running GSSAPI Proxy Daemon
	  iprdump.service                       loaded active running LSB: Start the ipr dump daemon
	  iprinit.service                       loaded active running LSB: Start the ipr init daemon
	  iprupdate.service                     loaded active running LSB: Start the iprupdate utility
	  kdump.service                         loaded active exited  Crash recovery kernel arming
	  kmod-static-nodes.service             loaded active exited  Create list of required static device
	  lvm2-lvmetad.service                  loaded active running LVM2 metadata daemon
	  lvm2-monitor.service                  loaded active exited  Monitoring of LVM2 mirrors, snapshots
	  lvm2-pvscan@8:17.service              loaded active exited  LVM2 PV scan on device 8:17
	  lvm2-pvscan@8:18.service              loaded active exited  LVM2 PV scan on device 8:18
	  lvm2-pvscan@8:19.service              loaded active exited  LVM2 PV scan on device 8:19

	lines 1-18

[root@localhost ~]# systemctl enable crond.service
[root@localhost ~]# systemctl disable crond.service
	Removed symlink /etc/systemd/system/multi-user.target.wants/crond.service.
[root@localhost ~]# systemctl enable crond.service
	Created symlink from /etc/systemd/system/multi-user.target.wants/crond.service to /usr/lib/systemd/system/crond.service.
[root@localhost ~]# systemctl status crond.service
	● crond.service - Command Scheduler
	   Loaded: loaded (/usr/lib/systemd/system/crond.service; enabled; vendor preset: enabled)
	   Active: active (running) since Tue 2017-12-05 00:02:52 CST; 4h 42min ago
	 Main PID: 3052 (crond)
	   CGroup: /system.slice/crond.service
	           └─3052 /usr/sbin/crond -n

	Dec 05 00:02:52 localhost.localdomain crond[3052]: (CRON) INFO (RANDOM_DELAY will be scaled wi....)
	Dec 05 00:02:52 localhost.localdomain systemd[1]: Started Command Scheduler.
	Dec 05 00:02:52 localhost.localdomain crond[3052]: (CRON) INFO (running with inotify support)
	Dec 05 00:02:52 localhost.localdomain systemd[1]: Starting Command Scheduler...
	Dec 05 00:02:52 localhost.localdomain crond[3052]: (CRON) INFO (@reboot jobs will be run at co....)
	Hint: Some lines were ellipsized, use -l to show in full.
[root@localhost ~]# systemctl is-enabled crond.service
	enabled

disable的路徑session

[root@localhost ~]# ls -l /etc/systemd/system/multi-user.target.wants/crond.service 
	lrwxrwxrwx 1 root root 37 Dec  5 04:44 /etc/systemd/system/multi-user.target.wants/crond.service -> /usr/lib/systemd/system/crond.service

能夠看出這是個連接路徑，而真正的路徑/usr/lib/systemd/system/crond.serviceapp

[root@localhost ~]# systemctl disable crond.service
	Removed symlink /etc/systemd/system/multi-user.target.wants/crond.service.
[root@localhost ~]# ls -l /etc/systemd/system/multi-user.target.wants/crond.service 
	ls: cannot access /etc/systemd/system/multi-user.target.wants/crond.service: No such file or directory

unit

ls /usr/lib/systemd/system #系統全部unit，分爲如下類型
service 系統服務
target 多個unit組成的組
device 硬件設備
mount 文件系統掛載點
automount 自動掛載點
path 文件或路徑
scope 不是由systemd啓動的外部進程
slice 進程組
snapshot 不是由systemd啓動的外部進程
socket systemd快照
swap swap文件
timer 定時器

系統全部unitdom

[root@localhost ~]# ls /usr/lib/systemd/system/
	arp-ethers.service                      quotaon.service
	auditd.service                          rc-local.service
	auth-rpcgss-module.service              rdisc.service
	autovt@.service                         reboot.target
	avahi-daemon.service                    reboot.target.wants
	avahi-daemon.socket                     remote-fs-pre.target
	basic.target                            remote-fs.target
	basic.target.wants                      rescue.service
	blk-availability.service                rescue.target
	bluetooth.target                        rescue.target.wants
	brandbot.path                           rhel-autorelabel-mark.service
	brandbot.service                        rhel-autorelabel.service
	console-getty.service                   rhel-configure.service
	console-shell.service                   rhel-dmesg.service
	container-getty@.service                rhel-domainname.service
	cpupower.service                        rhel-import-state.service
	.
	.
	.

[root@localhost ~]# ls -l /usr/lib/systemd/system/runlevel*
lrwxrwxrwx. 1 root root 15 Nov 23 15:36 /usr/lib/systemd/system/runlevel0.target -> poweroff.target
lrwxrwxrwx. 1 root root 13 Nov 23 15:36 /usr/lib/systemd/system/runlevel1.target -> rescue.target
lrwxrwxrwx. 1 root root 17 Nov 23 15:36 /usr/lib/systemd/system/runlevel2.target -> multi-user.target
lrwxrwxrwx. 1 root root 17 Nov 23 15:36 /usr/lib/systemd/system/runlevel3.target -> multi-user.target
lrwxrwxrwx. 1 root root 17 Nov 23 15:36 /usr/lib/systemd/system/runlevel4.target -> multi-user.target
lrwxrwxrwx. 1 root root 16 Nov 23 15:36 /usr/lib/systemd/system/runlevel5.target -> graphical.target
lrwxrwxrwx. 1 root root 13 Nov 23 15:36 /usr/lib/systemd/system/runlevel6.target -> reboot.target

/usr/lib/systemd/system/runlevel1.target.wants:
total 0
lrwxrwxrwx. 1 root root 39 Nov 23 15:36 systemd-update-utmp-runlevel.service -> ../systemd-update-utmp-runlevel.service

/usr/lib/systemd/system/runlevel2.target.wants:
total 0
lrwxrwxrwx. 1 root root 39 Nov 23 15:36 systemd-update-utmp-runlevel.service -> ../systemd-update-utmp-runlevel.service

/usr/lib/systemd/system/runlevel3.target.wants:
total 0
lrwxrwxrwx. 1 root root 39 Nov 23 15:36 systemd-update-utmp-runlevel.service -> ../systemd-update-utmp-runlevel.service

/usr/lib/systemd/system/runlevel4.target.wants:
total 0
lrwxrwxrwx. 1 root root 39 Nov 23 15:36 systemd-update-utmp-runlevel.service -> ../systemd-update-utmp-runlevel.service

/usr/lib/systemd/system/runlevel5.target.wants:
total 0
lrwxrwxrwx. 1 root root 39 Nov 23 15:36 systemd-update-utmp-runlevel.service -> ../systemd-update-utmp-runlevel.service

unit相關的命令
systemctl list-units #列出正在運行的unit
systemctl list-units --all #列出全部，包括失敗的或者inactive
systemctl list-units --all --state=inactive #列出inactive的unit
systemctl list-units --type=service #列出狀態爲active的service
systemctl list is-active crond.service #查看某個服務是否爲active

[root@localhost ~]# systemctl list-units
	  UNIT                                 LOAD   ACTIVE SUB       DESCRIPTION
	  proc-sys-fs-binfmt_misc.automount    loaded active waiting   Arbitrary Executable File Formats Fi
	  sys-devices-pci0000:00-0000:00:07.1-ata2-host2-target2:0:0-2:0:0:0-block-sr0.device loaded active
	  sys-devices-pci0000:00-0000:00:10.0-host0-target0:0:0-0:0:0:0-block-sda-sda1.device loaded active
	  sys-devices-pci0000:00-0000:00:10.0-host0-target0:0:0-0:0:0:0-block-sda-sda2.device loaded active
	  sys-devices-pci0000:00-0000:00:10.0-host0-target0:0:0-0:0:0:0-block-sda-sda3.device loaded active
	  sys-devices-pci0000:00-0000:00:10.0-host0-target0:0:0-0:0:0:0-block-sda.device loaded active plug
	  sys-devices-pci0000:00-0000:00:10.0-host0-target0:0:1-0:0:1:0-block-sdb-sdb1.device loaded active
	  sys-devices-pci0000:00-0000:00:10.0-host0-target0:0:1-0:0:1:0-block-sdb-sdb2.device loaded active
	  sys-devices-pci0000:00-0000:00:10.0-host0-target0:0:1-0:0:1:0-block-sdb-sdb3.device loaded active
	  sys-devices-pci0000:00-0000:00:10.0-host0-target0:0:1-0:0:1:0-block-sdb.device loaded active plug
	  sys-devices-pci0000:00-0000:00:11.0-0000:02:01.0-net-eno16777736.device loaded active plugged   P
	  sys-devices-pci0000:00-0000:00:11.0-0000:02:02.0-sound-card0.device loaded active plugged   Audio
	  sys-devices-pci0000:00-0000:00:11.0-0000:02:05.0-net-ens37.device loaded active plugged   PRO/100
	  sys-devices-platform-serial8250-tty-ttyS1.device loaded active plugged   /sys/devices/platform/se
	  sys-devices-platform-serial8250-tty-ttyS2.device loaded active plugged   /sys/devices/platform/se
	  sys-devices-platform-serial8250-tty-ttyS3.device loaded active plugged   /sys/devices/platform/se
	  sys-devices-pnp0-00:08-tty-ttyS0.device loaded active plugged   /sys/devices/pnp0/00:08/tty/ttyS0

	lines 1-18

[root@localhost ~]# systemctl list-units --all
	  UNIT                                LOAD      ACTIVE   SUB       DESCRIPTION
	  proc-sys-fs-binfmt_misc.automount   loaded    active   waiting   Arbitrary Executable File Format
	  dev-block-8:17.device               loaded    active   plugged   LVM PV DEzGdZ-eZpX-qWYI-XndU-e5X
	  dev-block-8:18.device               loaded    active   plugged   LVM PV QI4y20-GOdg-8CBJ-PfZF-GO8
	  dev-block-8:19.device               loaded    active   plugged   LVM PV JeafFf-5aVO-xNf2-DUv6-17S
	  dev-cdrom.device                    loaded    active   plugged   VMware_Virtual_IDE_CDROM_Drive C
	  dev-disk-by\x2did-ata\x2dVMware_Virtual_IDE_CDROM_Drive_10000000000000000001.device loaded    act
	  dev-disk-by\x2did-dm\x2dname\x2dvg1\x2dlv1.device loaded    active   plugged   /dev/disk/by-id/dm
	  dev-disk-by\x2did-dm\x2duuid\x2dLVM\x2dad3wQ3M3m1btaWae4bRhQl9iPMxBDFaSbxXagDlt0CiJLOnaqpvj6Vvsyq
	  dev-disk-by\x2did-lvm\x2dpv\x2duuid\x2dDEzGdZ\x2deZpX\x2dqWYI\x2dXndU\x2de5X9\x2dSEcT\x2dMsiLCc.d
	  dev-disk-by\x2did-lvm\x2dpv\x2duuid\x2dJeafFf\x2d5aVO\x2dxNf2\x2dDUv6\x2d17S2\x2dN8Cg\x2df0E3vX.d
	  dev-disk-by\x2did-lvm\x2dpv\x2duuid\x2dQI4y20\x2dGOdg\x2d8CBJ\x2dPfZF\x2dGO8l\x2dambD\x2df7Jikz.d
	  dev-disk-by\x2dlabel-CentOS\x5cx207\x5cx20x86_64.device loaded    active   plugged   VMware_Virtu
	  dev-disk-by\x2dpath-pci\x2d0000:00:07.1\x2data\x2d2.0.device loaded    active   plugged   VMware_
	  dev-disk-by\x2dpath-pci\x2d0000:00:10.0\x2dscsi\x2d0:0:0:0.device loaded    active   plugged   VM
	  dev-disk-by\x2dpath-pci\x2d0000:00:10.0\x2dscsi\x2d0:0:0:0\x2dpart1.device loaded    active   plu
	  dev-disk-by\x2dpath-pci\x2d0000:00:10.0\x2dscsi\x2d0:0:0:0\x2dpart2.device loaded    active   plu
	  dev-disk-by\x2dpath-pci\x2d0000:00:10.0\x2dscsi\x2d0:0:0:0\x2dpart3.device loaded    active   plu

	lines 1-18

[root@localhost ~]# systemctl list-units --all --state=inactive
	  UNIT                                  LOAD      ACTIVE   SUB  DESCRIPTION
	  proc-sys-fs-binfmt_misc.mount         loaded    inactive dead Arbitrary Executable File Formats F
	  sys-fs-fuse-connections.mount         loaded    inactive dead FUSE Control File System
	  tmp.mount                             loaded    inactive dead Temporary Directory
	  systemd-ask-password-console.path     loaded    inactive dead Dispatch Password Requests to Conso
	  auth-rpcgss-module.service            loaded    inactive dead Kernel Module supporting RPCSEC_GSS
	  brandbot.service                      loaded    inactive dead Flexible Branding Service
	  cpupower.service                      loaded    inactive dead Configure CPU power related setting
	● display-manager.service               not-found inactive dead display-manager.service
	  dm-event.service                      loaded    inactive dead Device-mapper event daemon
	  dracut-shutdown.service               loaded    inactive dead Restore /run/initramfs
	  ebtables.service                      loaded    inactive dead Ethernet Bridge Filtering tables
	  emergency.service                     loaded    inactive dead Emergency Shell
	● exim.service                          not-found inactive dead exim.service
	  ip6tables.service                     loaded    inactive dead IPv6 firewall with ip6tables
	  iptables.service                      loaded    inactive dead IPv4 firewall with iptables
	  irqbalance.service                    loaded    inactive dead irqbalance daemon
	● libvirtd.service                      not-found inactive dead libvirtd.service

	lines 1-18

僅列出active和failedssh

[root@localhost ~]# systemctl list-units --type=service
	  UNIT                                  LOAD   ACTIVE SUB     DESCRIPTION
	  auditd.service                        loaded active running Security Auditing Service
	  avahi-daemon.service                  loaded active running Avahi mDNS/DNS-SD Stack
	  crond.service                         loaded active running Command Scheduler
	  dbus.service                          loaded active running D-Bus System Message Bus
	  firewalld.service                     loaded active running firewalld - dynamic firewall daemon
	  getty@tty1.service                    loaded active running Getty on tty1
	  gssproxy.service                      loaded active running GSSAPI Proxy Daemon
	  iprdump.service                       loaded active running LSB: Start the ipr dump daemon
	  iprinit.service                       loaded active running LSB: Start the ipr init daemon
	  iprupdate.service                     loaded active running LSB: Start the iprupdate utility
	  kdump.service                         loaded active exited  Crash recovery kernel arming
	  kmod-static-nodes.service             loaded active exited  Create list of required static device
	  lvm2-lvmetad.service                  loaded active running LVM2 metadata daemon
	  lvm2-monitor.service                  loaded active exited  Monitoring of LVM2 mirrors, snapshots
	  lvm2-pvscan@8:17.service              loaded active exited  LVM2 PV scan on device 8:17
	  lvm2-pvscan@8:18.service              loaded active exited  LVM2 PV scan on device 8:18
	  lvm2-pvscan@8:19.service              loaded active exited  LVM2 PV scan on device 8:19

	lines 1-18

列出全部socket

[root@localhost ~]# systemctl list-units --all --type=service
	  UNIT                                 LOAD      ACTIVE   SUB     DESCRIPTION
	  auditd.service                       loaded    active   running Security Auditing Service
	  auth-rpcgss-module.service           loaded    inactive dead    Kernel Module supporting RPCSEC_G
	  avahi-daemon.service                 loaded    active   running Avahi mDNS/DNS-SD Stack
	  brandbot.service                     loaded    inactive dead    Flexible Branding Service
	  cpupower.service                     loaded    inactive dead    Configure CPU power related setti
	  crond.service                        loaded    active   running Command Scheduler
	  dbus.service                         loaded    active   running D-Bus System Message Bus
	● display-manager.service              not-found inactive dead    display-manager.service
	  dm-event.service                     loaded    inactive dead    Device-mapper event daemon
	  dracut-shutdown.service              loaded    inactive dead    Restore /run/initramfs
	  ebtables.service                     loaded    inactive dead    Ethernet Bridge Filtering tables
	  emergency.service                    loaded    inactive dead    Emergency Shell
	● exim.service                         not-found inactive dead    exim.service
	  firewalld.service                    loaded    active   running firewalld - dynamic firewall daem
	  getty@tty1.service                   loaded    active   running Getty on tty1
	  gssproxy.service                     loaded    active   running GSSAPI Proxy Daemon
	  ip6tables.service                    loaded    inactive dead    IPv6 firewall with ip6tables

	lines 1-18

[root@localhost ~]# systemctl is-active crond.service
	active
[root@localhost ~]# systemctl is-enabled crond.service
	disabled

target

系統爲了方便管理用target來管理unit
systemctl list-unit-files --type=target
systemctl list-dependencies multi-user.target #查看指定target下面有哪些unit
systemctl get-default #查看系統默認的target
systemctl set-default multi-user.target
一個service屬於一種類型的unit
多個unit組成了一個target
一個target裏面包含了多個service
cat /usr/lib/systemd/system/sshd.service #查看[install]部分

[root@localhost ~]# systemctl list-units --type=target
	UNIT                  LOAD   ACTIVE SUB    DESCRIPTION
	basic.target          loaded active active Basic System
	cryptsetup.target     loaded active active Encrypted Volumes
	getty.target          loaded active active Login Prompts
	local-fs-pre.target   loaded active active Local File Systems (Pre)
	local-fs.target       loaded active active Local File Systems
	multi-user.target     loaded active active Multi-User System
	network-online.target loaded active active Network is Online
	network.target        loaded active active Network
	nfs-client.target     loaded active active NFS client services
	nss-lookup.target     loaded active active Host and Network Name Lookups
	paths.target          loaded active active Paths
	remote-fs-pre.target  loaded active active Remote File Systems (Pre)
	remote-fs.target      loaded active active Remote File Systems
	slices.target         loaded active active Slices
	sockets.target        loaded active active Sockets
	sound.target          loaded active active Sound Card
	swap.target           loaded active active Swap

	lines 1-18

[root@localhost ~]# systemctl list-dependencies multi-user.target
	multi-user.target
	● ├─auditd.service
	● ├─avahi-daemon.service
	● ├─brandbot.path
	● ├─dbus.service
	● ├─iprdump.service
	● ├─iprinit.service
	● ├─iprupdate.service
	● ├─irqbalance.service
	● ├─kdump.service
	● ├─network.service
	● ├─NetworkManager.service
	● ├─nfs-server.service
	● ├─plymouth-quit-wait.service
	● ├─plymouth-quit.service
	● ├─postfix.service
	● ├─rsyslog.service
	● ├─sshd.service

	lines 1-18

系統默認targetpost

[root@localhost ~]# systemctl get-default
	multi-user.target

設置默認targetui

[root@localhost ~]# 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@localhost ~]# ls -l /etc/systemd/system/default.target
	lrwxrwxrwx 1 root root 41 Dec  5 09:07 /etc/systemd/system/default.target -> /usr/lib/systemd/system/multi-user.target

設置默認target的同時，會生成軟連接spa

多個unit組成了一個target 一個target裏面包含了多個service

查看[install]部分

[root@localhost ~]# cat /usr/lib/systemd/system/sshd.service 
	[Unit]
	Description=OpenSSH server daemon
	After=syslog.target network.target auditd.service
	
	[Service]
	EnvironmentFile=/etc/sysconfig/sshd
	ExecStartPre=/usr/sbin/sshd-keygen
	ExecStart=/usr/sbin/sshd -D $OPTIONS
	ExecReload=/bin/kill -HUP $MAINPID
	KillMode=process
	Restart=on-failure
	RestartSec=42s
	
	[Install]
	WantedBy=multi-user.target

經過查看[install]部分咱們能夠得知屬於哪一個target

對比

[root@localhost ~]# cat /usr/lib/systemd/system/crond.service 
	[Unit]
	Description=Command Scheduler
	After=syslog.target auditd.service systemd-user-sessions.service time-sync.target

	[Service]
	EnvironmentFile=/etc/sysconfig/crond
	ExecStart=/usr/sbin/crond -n $CRONDARGS
	KillMode=process

	[Install]
	WantedBy=multi-user.target