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systemctl命令使用说明

时间:2019-10-17 16:53:51      阅读:64      评论:0      收藏:0      [点我收藏+]

1、命令概述

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。

在Linux生态系统中,Systemd被部署到了大多数的标准Linux发行版中,只有为数不多的几个发行版尚未部署。Systemd通常是所有其它守护进程的父进程,但并非总是如此。

CentOS7之后从init完全换成了systemd的启动方式,systemd 启动服务的机制主要是通过 systemctl 的这个系统服务管理指令来处理。systemctl在用法上也囊括 service / chkconfig / setup / init 的大部分功能。

2、命令语法

systemctl【选项】 【服务】 

3、命令选项

status:查看服务状态
start:启动服务
stop:停止服务
restart:重启服务
enable:使某服务开机自启
disable:关闭某服务开机自启
list-units:列举所有运行中单元
list-unit-files:列出所有可用单元
list-unit-files --type=service:列出所有服务(包括启用和禁用)
list-unit-files --type=mount:列出所有系统挂载点
list-unit-files –type=socket:列出所有可用系统套接口
list-failed:列出所有启动失败的服务
is-enabled:查看某个服务是否开机自启
is-active:查看某个服务现在是否开启
kill:杀死某个服务
reload:重新加载某个服务配置文件
show:检查某个服务的所有配置细节
list-dependencies:获取某个服务的依赖性列表
get-default:列出当前系统的运行等级
mask:屏蔽(使其无法启动)某个服务
umask:取消屏蔽

4、命令示例

4.1 status 查看 firewalld 服务的状态

 1 [root@localhost ~]# systemctl status firewalld.service
 2 ● firewalld.service - firewalld - dynamic firewall daemon  3 Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)  4 Active: active (running) since 二 2019-10-08 15:58:24 CST; 1 weeks 1 days ago  5 Docs: man:firewalld(1)  6 Main PID: 12434 (firewalld)  7 CGroup: /system.slice/firewalld.service  8 └─12434 /usr/bin/python2 -Es /usr/sbin/firewalld --nofork --nopid  9 10 10月 08 15:58:24 localhost.localdomain systemd[1]: Starting firewalld - dynamic firewall daemon... 11 10月 08 15:58:24 localhost.localdomain systemd[1]: Started firewalld - dynamic firewall daemon. 12 [root@localhost ~]#

4.2 start 启动 firewalld服务

1 [root@localhost ~]# systemctl start firewalld.service

4.3 stop 停止 firewalld 服务

1 [root@localhost ~]# systemctl stop firewalld.service

4.4 restart 重启 firewalld 服务

1 [root@localhost ~]# systemctl restart firewalld.service

4.5 enable 开启 firewalld 服务开机自动启动

1 [root@localhost ~]# systemctl enable firewalld.service

4.6 disable 关闭 firewalld 服务开机自动启动

1 [root@localhost ~]# systemctl disable firewalld.service
2 Removed symlink /etc/systemd/system/multi-user.target.wants/firewalld.service. 3 Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service. 4 [root@localhost ~]#

4.7 list-units:列举所有运行中单元

1 [root@localhost ~]# systemctl list-units

4.8 list-unit-files:列出所有可用单元

1 [root@localhost ~]# systemctl list-unit-files

4.9 --list-failed:列出所有失败的服务

1 [root@localhost ~]# systemctl --failed
2 0 loaded units listed. Pass --all to see loaded but inactive units, too.
3 To show all installed unit files use systemctl list-unit-files.
4 [root@localhost ~]# 

4.10 is-enabled 查看 firewalld 服务是否开机启动

1 [root@localhost ~]# systemctl is-enabled firewalld.service
2 enabled 3 [root@localhost ~]#

4.11 kill 杀死 firewalld 服务

 1 [root@localhost ~]# systemctl kill firewalld.service
 2 [root@localhost ~]# systemctl status firewalld.service
 3 ● firewalld.service - firewalld - dynamic firewall daemon
 4    Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
 5    Active: inactive (dead) since 四 2019-10-17 15:15:24 CST; 21s ago
 6      Docs: man:firewalld(1)
 7   Process: 3659 ExecStart=/usr/sbin/firewalld --nofork --nopid $FIREWALLD_ARGS (code=exited, status=0/SUCCESS)
 8  Main PID: 3659 (code=exited, status=0/SUCCESS)
 9 
10 10月 17 15:07:56 localhost.localdomain systemd[1]: Starting firewalld - dynamic firewall daemon...
11 10月 17 15:07:56 localhost.localdomain systemd[1]: Started firewalld - dynamic firewall daemon.
12 [root@localhost ~]# 

4.12 reload 重新加载 firewalld 服务

1 [root@localhost ~]# systemctl reload firewalld.service

4.13 is-active 查看 firewalld 服务现在是否开启

1 [root@localhost ~]# systemctl is-active firewalld.service
2 active
3 [root@localhost ~]# 

4.14 list-unit-files --type=service:列出所有服务

1 [root@localhost ~]# systemctl list-unit-files --type=service

4.15 list-unit-files --type=mount:列出所有系统挂载点

 1 [root@localhost ~]# systemctl list-unit-files --type=mount
 2 UNIT FILE                     STATE   
 3 dev-hugepages.mount           static  
 4 dev-mqueue.mount              static  
 5 proc-sys-fs-binfmt_misc.mount static  
 6 sys-fs-fuse-connections.mount static  
 7 sys-kernel-config.mount       static  
 8 sys-kernel-debug.mount        static  
 9 tmp.mount                     disabled
10 
11 7 unit files listed.
12 [root@localhost ~]# 

4.16 挂载、卸载、重新挂载、重载系统挂载点并检查系统中挂载点状态 

# systemctl start tmp.mount
# systemctl stop tmp.mount
# systemctl restart tmp.mount
# systemctl reload tmp.mount
# systemctl status tmp.mount
# systemctl is-active tmp.mount
# systemctl enable tmp.mount
# systemctl disable tmp.mount

4.17 列出所有可用系统套接口

1 [root@localhost ~]# systemctl list-unit-files –type=socket
2 UNIT FILE STATE
3 
4 0 unit files listed.
5 [root@localhost ~]# 

4.18 检查某个服务(firewalld)的所有配置细节 

1 [root@localhost ~]# systemctl show firewalld.service

4.19 获取某个服务(firewalld)的依赖性列表

1 [root@localhost ~]# systemctl list-dependencies firewalld.service

4.20 get-default:列出当前系统的运行等级

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

4.21 获取某个服务当前CPU的份额

1 [root@localhost ~]# systemctl show -p CPUShares firewalld.service
2 CPUShares=18446744073709551615
3 [root@localhost ~]# systemctl show -p CPUShares sshd.service
4 CPUShares=18446744073709551615
5 [root@localhost ~]# 
注意:每个服务的默认值都为CPUShare = 1024.您可以增加/减少进程的CPU份额。

4.22 将服务的CPU份额(httpd)限制为2000 CPUShares /

1 [root@localhost ~]# systemctl set-property httpd.service CPUShares=2000

注意:为服务设置CPUShare时,会创建一个名为service的目录(httpd.service.d),其中包含一个包含CPUShare Limit信息的文件90-CPUShares.conf。 您可以将文件视为:
# cat /etc/systemd/system/httpd.service.d/90-CPUShares.conf
[Service]
CPUShares=2000

4.23 分析服务的关键链(firewalld.service):

 1 [root@localhost ~]# systemd-analyze critical-chain firewalld.service
 2 The time after the unit is active or started is printed after the "@" character.
 3 The time the unit takes to start is printed after the "+" character.
 4 
 5 firewalld.service +267ms
 6 └─dbus.service @1.643s
 7   └─basic.target @1.627s
 8     └─sockets.target @1.627s
 9       └─dbus.socket @1.627s
10         └─sysinit.target @1.626s
11           └─systemd-update-utmp.service @1.615s +10ms
12             └─systemd-tmpfiles-setup.service @1.288s +14ms
13               └─rhel-import-state.service @1.232s +55ms
14                 └─local-fs.target @1.232s
15                   └─boot.mount @1.186s +45ms
16                     └─dev-disk-by\x2duuid-806549af\x2dd314\x2d4cb2\x2db124\x2d8599a95e12bd.device @1.186s
17 [root@localhost ~]# 

4.24 按层次列出控制组

 1 [root@localhost ~]# systemd-cgls 
 2 ├─1 /usr/lib/systemd/systemd --system --deserialize 23
 3 ├─user.slice
 4 │ └─user-0.slice
 5 │   └─session-255.scope
 6 │     ├─ 7970 systemd-cgls
 7 │     ├─ 7971 less
 8 │     ├─29914 sshd: root@pts/1    
 9 │     └─29918 -bash
10 └─system.slice
11   ├─firewalld.service
12   │ └─4430 /usr/bin/python2 -Es /usr/sbin/firewalld --nofork --nopid
13   ├─tuned.service
14   │ └─12941 /usr/bin/python2 -Es /usr/sbin/tuned -l -P
15   ├─polkit.service

4.25 根据CPU,内存,输入和输出列出控制组

 1 [root@localhost ~]# systemd-cgtop 
 2 Path                                                                                Tasks   %CPU   Memory  Input/s Output/s
 3 
 4 /                                                                                     174      -     1.4G        -        -
 5 /system.slice/NetworkManager.service                                                    1      -        -        -        -
 6 /system.slice/auditd.service                                                            1      -        -        -        -
 7 /system.slice/chronyd.service                                                           1      -        -        -        -
 8 /system.slice/crond.service                                                             1      -        -        -        -
 9 /system.slice/dbus.service                                                              1      -        -        -        -
10 /system.slice/firewalld.service                                                         1      -        -        -        -
11 /system.slice/irqbalance.service                                                        1      -        -        -        -
12 /system.slice/polkit.service                                                            1      -        -        -        -
13 /system.slice/postfix.service                                                           3      -        -        -        -
14 /system.slice/rsyslog.service                                                           1      -        -        -        -
15 /system.slice/sshd.service                                                              1      -        -        -        -
16 /system.slice/system-getty.slice/getty@tty1.service                                     1      -        -        -        -
17 /system.slice/systemd-journald.service                                                  1      -        -        -        -

4.26 启动救援模式 

1 [root@localhost ~]# systemctl rescue

4.27 进入紧急模式 

1 [root@localhost ~]# systemctl emergency

4.28 分析systemd启动过程

1 [root@localhost ~]# systemd-analyze 
2 Startup finished in 418ms (kernel) + 1.421s (initrd) + 3.471s (userspace) = 5.311s
3 [root@localhost ~]# 

4.29 分析每个进程在引导时花费的时间

 1 [root@localhost ~]# systemd-analyze blame
 2            354ms NetworkManager-wait-online.service
 3            294ms postfix.service
 4            280ms network.service
 5            267ms firewalld.service
 6            266ms dev-sda5.device
 7            185ms NetworkManager.service
 8            154ms tuned.service
 9            126ms auditd.service
10            102ms rhel-dmesg.service
11            101ms systemd-user-sessions.service
12             64ms sys-kernel-debug.mount
13             64ms dev-hugepages.mount
14             63ms systemd-remount-fs.service

4.30 分析启动时的关键链

1 [root@localhost ~]# systemd-analyze critical-chain
2 The time after the unit is active or started is printed after the "@" character.
3 The time the unit takes to start is printed after the "+" character.
4 
5 multi-user.target @3.469s
6 └─NetworkManager.service @2.549s +185ms
7   └─network-pre.target @2.548s
8 [root@localhost ~]# 

 

systemctl命令使用说明

原文:https://www.cnblogs.com/liuzgg/p/11693034.html

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