Linux下systemctl命令和service、chkconfig命令的区别
Systemctl和service、chkconfig命令的关系
1 systemctl命令：是一个systemd工具，主要负责控制systemd系统和服务管理器。 2 service命令：可以启动、停止、重新启动和关闭系统服务，还可以显示所有系统服务的当前状态。 3 chkconfig命令：是管理系统服务(service)的命令行工具。所谓系统服务(service)，就是随系统启动而启动，随系统关闭而关闭的程序。
systemctl命令是系统服务管理器指令，它实际上将 service 和 chkconfig 这两个命令组合到一起。
systemctl是RHEL 7 的服务管理工具中主要的工具，它融合之前service和chkconfig的功能于一体。可以使用它永久性或只在当前会话中启用/禁用服务。
所以systemctl命令是service命令和chkconfig命令的集合和代替。
例如：使用service启动服务实际上也是调用systemctl命令。
1 [root@localhost ~]# service httpd start 2 Redirecting to /bin/systemctl start httpd.service
systemctl命令的用法
Systemctl命令简介：
Systemctl是一个systemd工具，主要负责控制systemd系统和服务管理器。
Systemd是一个系统管理守护进程、工具和库的集合，用于取代System V初始进程。Systemd的功能是用于集中管理和配置类UNIX系统。
systemd即为system daemon,是linux下的一种init软件。
Systemctl命令常见用法：
（1）列出所有可用单元：
1 [root@alwen ~]# systemctl list-unit-files 2 UNIT FILE STATE 3 proc-sys-fs-binfmt_misc.automount static 4 -.mount generated 5 boot.mount generated 6 dev-hugepages.mount static 7 dev-mqueue.mount static 8 proc-sys-fs-binfmt_misc.mount static 9 sys-fs-fuse-connections.mount static 10 sys-kernel-config.mount static 11 sys-kernel-debug.mount static 12 tmp.mount disabled 13 systemd-ask-password-console.path static 14 systemd-ask-password-wall.path static 15 session-1.scope transient 16 session-3.scope transient 17 session-4.scope transient 18 session-5.scope transient 19 session-6.scope transient 20 session-7.scope transient 21 arp-ethers.service disabled 22 atd.service enabled 23 auditd.service enabled 24 autovt@.service enabled 25 blk-availability.service disabled 26 chrony-dnssrv@.service static 27 chrony-wait.service disabled 28 chronyd.service disabled 29 cockpit-motd.service static 30 cockpit-wsinstance-http-redirect.service static
（2）列出所有可用单元：
1 [root@alwen ~]# systemctl list-units 2 UNIT LOAD ACTIVE SUB DESCRIPTION 3 proc-sys-fs-binfmt_misc.automount loaded active waiting Arbitrary Executable File> 4 sys-devices-pci0000:00-0000:00:07.1-ata2-host1-target1:0:0-1:0:0:0-block-sr0.device loaded active plugged VMwar> 5 sys-devices-pci0000:00-0000:00:10.0-host2-target2:0:0-2:0:0:0-block-sda-sda1.device loaded active plugged VMwar> 6 sys-devices-pci0000:00-0000:00:10.0-host2-target2:0:0-2:0:0:0-block-sda-sda2.device loaded active plugged VMwar> 7 sys-devices-pci0000:00-0000:00:10.0-host2-target2:0:0-2:0:0:0-block-sda.device loaded active plugged VMware_Vir> 8 sys-devices-pci0000:00-0000:00:11.0-0000:02:01.0-net-ens33.device loaded active plugged 82545EM Gigabit Etherne> 9 sys-devices-pci0000:00-0000:00:11.0-0000:02:02.0-sound-card0.device loaded active plugged ES1371/ES1373 / Creat> 10 sys-devices-platform-serial8250-tty-ttyS1.device loaded active plugged /sys/devices/platform/ser> 11 sys-devices-platform-serial8250-tty-ttyS2.device loaded active plugged /sys/devices/platform/ser> 12 sys-devices-platform-serial8250-tty-ttyS3.device loaded active plugged /sys/devices/platform/ser> 13 sys-devices-pnp0-00:05-tty-ttyS0.device loaded active plugged /sys/devices/pnp0/00:05/t> 14 sys-devices-virtual-block-dm\x2d0.device loaded active plugged /sys/devices/virtual/bloc> 15 sys-devices-virtual-block-dm\x2d1.device loaded active plugged /sys/devices/virtual/bloc> 16 sys-module-configfs.device loaded active plugged /sys/module/configfs 17 sys-subsystem-net-devices-ens33.device loaded active plugged 82545EM Gigabit Ethernet > 18 -.mount loaded active mounted Root Mount 19 boot.mount loaded active mounted /boot 20 dev-hugepages.mount loaded active mounted Huge Pages File System 21 dev-mqueue.mount loaded active mounted POSIX Message Queue File > 22 run-user-0.mount loaded active mounted /run/user/0 23 sys-kernel-config.mount loaded active mounted Kernel Configuration File> 24 sys-kernel-debug.mount loaded active mounted Kernel Debug File System 25 systemd-ask-password-console.path loaded active waiting Dispatch Pass
(3)列出所有失败单元：
[root@alwen ~]# systemctl --failed 0 loaded units listed. Pass --all to see loaded but inactive units, too. To show all installed unit files use 'systemctl list-unit-files'.
4）检查某个单元是否启动：
1 [root@localhost ~]# systemctl is-enabled httpd.service 2 enabled
（5）检查某个服务的运行状态：
1 [root@alwen ~]# systemctl status httpd.service 2 ● httpd.service - The Apache HTTP Server 3 Loaded: loaded (/usr/lib/systemd/system/httpd.service; disabled; vendor preset: disabled) 4 Active: active (running) since Thu 2021-06-10 19:58:25 CST; 34min ago 5 Docs: man:httpd.service(8) 6 Main PID: 1919 (httpd) 7 Status: "Total requests: 2; Idle/Busy workers 100/0;Requests/sec: 0.00096; Bytes served/sec: 96 B/sec" 8 Tasks: 278 (limit: 11210) 9 Memory: 48.0M 10 CGroup: /system.slice/httpd.service 11 ├─1919 /usr/sbin/httpd -DFOREGROUND 12 ├─1920 /usr/sbin/httpd -DFOREGROUND 13 ├─1921 /usr/sbin/httpd -DFOREGROUND 14 ├─1922 /usr/sbin/httpd -DFOREGROUND 15 ├─1923 /usr/sbin/httpd -DFOREGROUND 16 └─2148 /usr/sbin/httpd -DFOREGROUND 17 18 Jun 10 19:58:25 alwen.com systemd[1]: Starting The Apache HTTP Server... 19 Jun 10 19:58:25 alwen.com systemd[1]: Started The Apache HTTP Server. 20 Jun 10 19:58:25 alwen.com httpd[1919]: Server configured, listening on: port 80
（6）列出所有服务：
1 [root@alwen ~]# systemctl list-unit-files --type=service 2 UNIT FILE STATE 3 arp-ethers.service disabled 4 atd.service enabled 5 auditd.service enabled 6 autovt@.service enabled 7 blk-availability.service disabled 8 chrony-dnssrv@.service static 9 chrony-wait.service disabled 10 chronyd.service disabled 11 cockpit-motd.service static 12 cockpit-wsinstance-http-redirect.service static 13 cockpit-wsinstance-http.service static 14 cockpit-wsinstance-https-factory@.service static 15 cockpit-wsinstance-https@.service static 16 cockpit.service static 17 console-getty.service disabled 18 container-getty@.service static 19 cpupower.service disabled 20 crond.service enabled 21 dbus-org.freedesktop.hostname1.service static 22 dbus-org.freedesktop.locale1.service static 23 dbus-org.freedesktop.login1.service static 24 dbus-org.freedesktop.nm-dispatcher.service enabled 25 dbus-org.freedesktop.portable1.service static 26 dbus-org.freedesktop.timedate1.service enabled 27 dbus.service static 28 debug-shell.service disabled 29 dm-event.service static 30 dnf-makecache.service static
（7）启动，停止，重启服务等：
1 [root@localhost ~]# systemctl restart httpd.service 2 # systemctl restart httpd.service 3 # systemctl stop httpd.service 4 # systemctl reload httpd.service 5 # systemctl status httpd.service
（8）查询服务是否激活，和配置是否开机启动：
1 [root@alwen ~]# systemctl is-active httpd 2 active 3 [root@alwen ~]# systemctl disable httpd 4 [root@alwen ~]# systemctl enable httpd 5 Created symlink /etc/systemd/system/multi-user.target.wants/httpd.service → /usr/lib/systemd/system/httpd.service. 6 [root@alwen ~]#
（9）使用systemctl命令杀死服务：
[root@alwen ~]# systemctl kill httpd
10）列出系统的各项服务，挂载，设备等：
1 [root@alwen ~]# systemctl list-unit-files 2 UNIT FILE STATE 3 proc-sys-fs-binfmt_misc.automount static 4 -.mount generated 5 boot.mount generated 6 dev-hugepages.mount static 7 dev-mqueue.mount static 8 proc-sys-fs-binfmt_misc.mount static 9 sys-fs-fuse-connections.mount static 10 sys-kernel-config.mount static 11 sys-kernel-debug.mount static 12 tmp.mount disabled 13 systemd-ask-password-console.path static 14 systemd-ask-password-wall.path static 15 session-1.scope transient 16 session-3.scope transient 17 session-4.scope transient 18 session-5.scope transient 19 session-6.scope transient 20 session-7.scope transient 21 arp-ethers.service disabled 22 atd.service enabled
（11）获得系统默认启动级别和设置默认启动级别：
1 [root@alwen ~]# systemctl get-default 2 multi-user.target
1 [root@localhost ~]# systemctl get-default 2 graphical.target 3 [root@localhost ~]# systemctl set-default multi-user.target
12）启动运行等级：
1 [root@alwen ~]# systemctl isolate multiuser.target 2 Failed to start multiuser.target: Operation refused, unit may not be isolated. 3 See system logs and 'systemctl status multiuser.target' for details.
（13）重启、停止，挂起、休眠系统等：
1 # systemctl reboot 2 # systemctl halt 3 # systemctl suspend 4 # systemctl hibernate 5 # systemctl hybrid-sleep
Service命令用法
service命令可以启动、停止、重新启动和关闭系统服务，还可以显示所有系统服务的当前状态。
service命令的作用是去/etc/init.d目录下寻找相应的服务，进行开启和关闭等操作。
使用示例：
开启关闭一个服务：service httpd start/stop
1 [root@localhost ~]# service httpd start 2 Redirecting to /bin/systemctl start httpd.service
查看系统服务的状态：service --status-all
1 [root@alwen ~]# service --status-all 2 [root@alwen ~]# service all status 3 Redirecting to /bin/systemctl status all.service 4 Unit all.service could not be found.
1 [root@localhost ~]# service --status-all 2 未加载 netconsole 模块 3 已配置设备： 4 lo ens33 ens33.old team0 team0-port1 team0-port1.old team0-port2 team0-port2.old team0.old 5 当前活跃设备： 6 lo ens33 virbr0 ens38 ens39 team0 7 ● rhnsd.service - LSB: Starts the Spacewalk Daemon 8 Loaded: loaded (/etc/rc.d/init.d/rhnsd; bad; vendor preset: disabled) 9 Active: active (running) since 五 2018-10-12 14:53:19 CST; 3 days ago 10 Docs: man:systemd-sysv-generator(8) 11 Main PID: 1380 (rhnsd) 12 CGroup: /system.slice/rhnsd.service 13 └─1380 rhnsd
chkconfig命令用法
chkconfig是管理系统服务(service)的命令行工具。所谓系统服务(service)，就是随系统启动而启动，随系统关闭而关闭的程序。
chkconfig可以更新(启动或停止)和查询系统服务(service)运行级信息。更简单一点，chkconfig是一个用于维护/etc/rc[0-6].d目录的命令行工具。
chkconfig常见用法：
1 [root@alwen ~]# chkconfig --help 2 chkconfig version 1.13 - Copyright (C) 1997-2000 Red Hat, Inc. 3 This may be freely redistributed under the terms of the GNU Public License. 4 5 usage: chkconfig [--list] [--type <type>] [name] 6 chkconfig --add <name> 7 chkconfig --del <name> 8 chkconfig --override <name> 9 chkconfig [--level <levels>] [--type <type>] <name> <on|off|reset|resetpriorities>
（一）设置service开机是否启动：
1 chkconfig name on/off/reset
- on、off、reset用于改变service的启动信息。
- on表示开启，off表示关闭，reset表示重置。
- 默认情况下，on和off开关只对运行级2，3，4，5有效，reset可以对所有运行级有效。
1 [root@alwen ~]# chkconfig httpd on 2 Note: Forwarding request to 'systemctl enable httpd.service'.
[root@localhost ~]# chkconfig httpd on 注意：正在将请求转发到“systemctl enable httpd.service”。
在Redhat7上，运行chkconfig命令，都会被转到systemcle命令上。
2）设置service运行级别：
1 [root@alwen ~]# chkconfig --level levels 2 chkconfig version 1.13 - Copyright (C) 1997-2000 Red Hat, Inc. 3 This may be freely redistributed under the terms of the GNU Public License. 4 5 usage: chkconfig [--list] [--type <type>] [name] 6 chkconfig --add <name> 7 chkconfig --del <name> 8 chkconfig --override <name> 9 chkconfig [--level <levels>] [--type <type>] <name> <on|off|reset|resetpriorities>
该命令可以用来指定服务的运行级别，即指定运行级别2,3,4,5等。
- 等级0表示：表示关机
- 等级1表示：单用户模式
- 等级2表示：无网络连接的多用户命令行模式
- 等级3表示：有网络连接的多用户命令行模式
- 等级4表示：不可用
- 等级5表示：带图形界面的多用户模式
- 等级6表示：重新启动
例如：
1 [root@localhost ~]# chkconfig --level 5 httpd on 2 注意：正在将请求转发到“systemctl enable httpd.service”
（三）列出service启动信息：
1 # chkconfig --list [name]
如果不指定name，会列出所有services的信息。
每个service每个运行级别都会有一个启动和停止脚本；当切换运行级别时，init不会重启已经启动的service，也不会重新停止已经停止的service。
例如：
1 [root@localhost ~]# chkconfig --list 2 3 注意：该输出结果只显示 SysV 服务，并不包含原生 systemd 服务。SysV 配置数据可能被原生 systemd 配置覆盖。 4 如果您想列出 systemd 服务,请执行 'systemctl list-unit-files'。 5 欲查看对特定 target 启用的服务请执行 6 'systemctl list-dependencies [target]'。 7 8 netconsole 0:关 1:关 2:关 3:关 4:关 5:关 6:关 9 network 0:关 1:关 2:开 3:开 4:开 5:开 6:关 10 rhnsd 0:关 1:关 2:开 3:开 4:开 5:开 6:关
1 [root@alwen ~]# systemctl list-dependencies 2 default.target 3 ● ├─atd.service 4 ● ├─auditd.service 5 ● ├─crond.service 6 ● ├─dbus.service 7 ● ├─httpd.service 8 ● ├─irqbalance.service 9 ● ├─kdump.service 10 ● ├─libstoragemgmt.service 11 ● ├─mcelog.service 12 ● ├─mdmonitor.service 13 ● ├─NetworkManager.service 14 ● ├─nvmefc-boot-connections.service 15 ● ├─smartd.service 16 ● ├─sshd.service 17 ● ├─sssd.service 18 ● ├─systemd-ask-password-wall.path 19 ● ├─systemd-logind.service 20 ● ├─systemd-update-utmp-runlevel.service 21 ● ├─systemd-user-sessions.service 22 ● ├─tuned.service 23 ● ├─vdo.service 24 ● ├─basic.target 25 ● │ ├─-.mount 26 ● │ ├─microcode.service 27 ● │ ├─paths.target 28 ● │ ├─slices.target 29 ● │ │ ├─-.slice 30 ● │ │ └─system.slice
**总结：**service命令的功能基本都被systemct取代。直接使用systemctl命令即可
查看linux系统的运行级别
查看当前系统的运行级别
[root@apenglinux ~]# runlevel
3 5
查看系统的默认级别
[root@apenglinux ~]# systemctl get-default
graphical.target
设置系统的默认运行级别为3
[root@apenglinux ~]# systemctl set-default multi-user.target
[root@apenglinux ~]# rm -f /etc/systemd/system/default.target
[root@apenglinux ~]# ln -sf /lib/systemd/system/multi-user.target /etc/systemd/system/default.target
设置系统的默认运行级别为5
[root@apenglinux ~]# systemctl set-default graphical.target
[root@apenglinux ~]# rm -f /etc/systemd/system/default.target
[root@apenglinux ~]# ln -sf /lib/systemd/system/graphical.target /etc/systemd/system/default.target
从3级别切换到5级别
init 5
systemctl isolate graphical.target
从5级别切换到3级别
init 3
systemctl isolate multi-user.target
查看系统的运行级别
[root@apenglinux ~]# ls -l /lib/systemd/system/runlevel*target
lrwxrwxrwx. 1 root root 15 1月 18 17:03 /lib/systemd/system/runlevel0.target -> poweroff.target
lrwxrwxrwx. 1 root root 13 1月 18 17:03 /lib/systemd/system/runlevel1.target -> rescue.target
lrwxrwxrwx. 1 root root 17 1月 18 17:03 /lib/systemd/system/runlevel2.target -> multi-user.target
lrwxrwxrwx. 1 root root 17 1月 18 17:03 /lib/systemd/system/runlevel3.target -> multi-user.target
lrwxrwxrwx. 1 root root 17 1月 18 17:03 /lib/systemd/system/runlevel4.target -> multi-user.target
lrwxrwxrwx. 1 root root 16 1月 18 17:03 /lib/systemd/system/runlevel5.target -> graphical.target
lrwxrwxrwx. 1 root root 13 1月 18 17:03 /lib/systemd/system/runlevel6.target -> reboot.target