7系统管理

系统管理

概念

进程

服务

守护进程

查看有哪些服务

 

命令

systemctl

用法：systemctl start|stop|restart|status 服务名

案例：

systemctl stop NetworkManger # 关闭网络服务

运行级别

centos7的运行级别

 

 查看当前的系统运行级别：systemctl get-default

[root@192 ~]# systemctl get-default 
graphical.target

 修改当前的系统运行级别：systemctl set-default

[root@192 ~]# systemctl set-default graphical.target 

 配置服务开机自启动

centos6 

chkconfig --list # 查询系统服务的运行级信息
chkconfig network off # 将network服务的开机自启动选项关闭
chkconfig network on # 将network服务的开机自启动选项开启
chkconfig --level 3 network off # 将运行级别3的network服务开启自启动选项关闭

centos7 

查看某个服务是否为开机自启动：systemctl status 服务名

[root@192 ~]# systemctl status NetworkManager # 查看networkmanager服务是否为开机自启动 enabled表示开机自启动
● NetworkManager.service - Network Manager
   Loaded: loaded (/usr/lib/systemd/system/NetworkManager.service; enabled; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:NetworkManager(8)

将某个服务的开机自启动选项关闭：systemctl disable 服务名

[root@192 ~]# systemctl disable NetworkManager # 将networkmanager服务的自启动选项设置为关闭
# disable表示关闭，NetworkManger为服务名
Removed symlink /etc/systemd/system/multi-user.target.wants/NetworkManager.service.
Removed symlink /etc/systemd/system/dbus-org.freedesktop.nm-dispatcher.service.
Removed symlink /etc/systemd/system/network-online.target.wants/NetworkManager-wait-online.service.
[root@192 ~]# systemctl status NetworkManager # 再次查看状态。当前为disabled表示关闭状态
● NetworkManager.service - Network Manager
   Loaded: loaded (/usr/lib/systemd/system/NetworkManager.service; disabled; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:NetworkManager(8)

将某个服务的开机自启动选项开启：systemctl enable 服务名

 [root@192 ~]# systemctl enable NetworkManager # 将networkManger服务的开机自启动选项设置为开启
# enable表示开启，后者为服务名
[root@192 ~]# systemctl status NetworkManager # 再次查看状态。enabled表示开启
● NetworkManager.service - Network Manager
   Loaded: loaded (/usr/lib/systemd/system/NetworkManager.service; enabled; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:NetworkManager(8)

查看开机自启动列表：systemctl list-unit-files

[root@192 ~]# 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  
run-vmblock\x2dfuse.mount                     disabled
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
cups.path                                     enabled 
systemd-ask-password-console.path             static  
systemd-ask-password-plymouth.path            static  
systemd-ask-password-wall.path                static  
session-2.scope                               static  
session-3.scope                               static  
session-6.scope                               static  
abrt-ccpp.service                             enabled 
abrt-oops.service                             enabled 

关闭和开启防火墙服务systemctl start/stop firewalld（加不加service都行）

[root@192 ~]# systemctl stop firewalld.service  # 关闭防火墙，stop表示关闭，换成start表示开启
[root@192 ~]# systemctl status firewalld # 再次查看防火墙状态。inactive表示关闭
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
   Active: inactive (dead) since 二 2024-01-09 20:04:56 CST; 2s ago
     Docs: man:firewalld(1)
  Process: 757 ExecStart=/usr/sbin/firewalld --nofork --nopid $FIREWALLD_ARGS (code=exited, status=0/SUCCESS)
 Main PID: 757 (code=exited, status=0/SUCCESS)

关机重启

sync：将数据从内存中同步到硬盘

halt：停机关闭系统，但不断电

poweroff：关机，断电

reboot：重启

shutdown 选项 时间

shutdown的选项

1. -H：相当于--halt，停机
2. -h：相当于poweroff，关机
3. -r ：相当于reboot，重启

shutdown的时间

1. now：立刻关机
2. 数字：等待多久关机（单位：分钟）
3. 时间：到几点关机(15:20)