控制服务和守护进程

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控制服务和守护进程

1.centos6

命令说明	输入命令
启动服务	service httpd start
关闭服务	service httpd stop
重启服务	service httpd restart
查看服务状态	service httpd status
设置服务开机启动	chkconfig httpd on
设置服务开机关闭	chkconfig httpd off
查看服务开机启动	chkconfig –list systemctl l

例子

[root@centos6 ~]# service httpd start
[root@centos6 ~]# service httpd stop
[root@centos6 ~]# service httpd restart
[root@centos6 ~]# chkconfig httpd on
注意：正在将请求转发到“systemctl enable vsftpd.service”。
Created symlink from /etc/systemd/system/multi-user.target.wants/httpd.service to /usr/lib/systemd/system/httpd.service.
[root@centos6 ~]# chkconfig httpd off
注意：正在将请求转发到“systemctl disable httpds.ervice”。
Removed symlink /etc/systemd/system/multi-user.target.wants/httpd.service
[root@centos6 ~]# service httpd status
Redirecting to /bin/systemctl status httpd.service
● vsftpd.service - httpd daemon
   Loaded: loaded (/usr/lib/systemd/system/httpd.service; disabled; vendor preset: disabled)
   Active: active (running) since 一 2018-11-19 10:32:32 CST; 3h 35min ago
 Main PID: 3158 (vsftpd)
   CGroup: /system.slice/httpd.service
           └─3158 /usr/sbin/httpd/etc/vsftpd/httpd.conf

11月 19 10:32:32 localhost.localdomain systemd[1]: Starting httpd ftp daemon...
11月 19 10:32:32 localhost.localdomain systemd[1]: Started httpd ftp daemon.

2.centos7

命令说明	输入命令
启动服务	systemctl start httpd.service
关闭服务	systemctl stop httpd.service
重启服务	systemctl restart httpd.service
查看服务状态	systemctl status httpd.service
设置服务开机启动	systemctl enable httpd.service
设置服务开机关闭	systemctl disable httpd.service
查看服务开机启动	systemctl list-units –type=service
重载或重启服务	reload-or-restart name.service
重载或条件式重启服务	reload-or-try-restart name.service
禁止设定为开机自启	mask name.service
取消禁止设定为开机自启	umask name.service
查看服务依赖关系	systemctl list-dependencies name.service
查看服务是否激活与否	systemctl is-active httpd.service
查看开机是否启动	systemctl enable httpd.service
禁止服务开机自动启动	systemctl disable httpd.service
设定某服务开机自动启动	systemctl enable name.service
禁止服务开机自动启动	systemctl isolate name.target
查看所有服务的开机自动启动状态（是否开机自启）	systemctl list-units --type service
查看所有的级别	systemctl list -units --type target --all
查看默认运行级别	get-default
设置默认运行级别	set-default name.target
切换至emergency模式（驱动不会加载，系统不会初始化，服务不会启动）	emergency
关机	halt
关机	poweroff
重启	reboot
挂起系统，此时不能关机，否则无用	suspend
创建并保存系统快照，下次系统重启时会自动载入快照	hibernate
混合睡眠，快照并挂起	hybrid-sleep

[root@centos7 ~]#systemctl start httpd.service
[root@centos7 ~]#systemctl stop httpd.service
[root@centos7 ~]#systemctl restart httpd.service
[root@centos7 ~]#systemctl status httpd.service
[root@centos7 ~]# systemctl enable httpd.service
Created symlink from /etc/systemd/system/multi-user.target.wants/httpd.service to /usr/lib/systemd/system/httpd.service.
[root@centos7 ~]# systemctl disable httpd.service
Removed symlink /etc/systemd/system/multi-user.target.wants/httpd.service.
[root@centos7 ~]# systemctl list-units –type=service
0 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.
[root@centos7 ~]# systemctl list-dependencies httpd.service
httpd.service
● ├─-.mount
● ├─system.slice
● └─basic.target
●   ├─microcode.service
●   ├─rhel-dmesg.service
●   ├─[email protected]
●   ├─paths.target
●   ├─slices.target
●   │ ├─-.slice
●   │ └─system.slice
●   ├─sockets.target
●   │ ├─dbus.socket
●   │ ├─dm-event.socket
●   │ ├─systemd-initctl.socket
●   │ ├─systemd-journald.socket
●   │ ├─systemd-shutdownd.socket
●   │ ├─systemd-udevd-control.socket
●   │ └─systemd-udevd-kernel.socket
●   ├─sysinit.target
●   │ ├─dev-hugepages.mount
●   │ ├─dev-mqueue.mount
[root@centos7 ~]# systemctl is-active httpd.service
unknown
[root@centos7 ~]# systemctl  enable httpd.service
Created symlink from /etc/systemd/system/multi-user.target.wants/httpd.service to /usr/lib/systemd/system/httpd.service.
[root@centos7 ~]# systemctl disable httpd.service 
Removed symlink /etc/systemd/system/multi-user.target.wants/httpd.service.

3.centos6和centos7服务命令对比

指令名称	centos 6	centos7
启动服务	service httpd start	systemctl start httpd.service
关闭服务	service httpd stop	systemctl stop httpd.service
重启服务	service httpd restart	systemctl restart httpd.service
查看服务状态	service httpd status	systemctl status httpd.service
设置服务开机启动	chkconfig httpd on	systemctl enable httpd.service
设置服务开机关闭	chkconfig httpd off	systemctl disable httpd.service
查看服务开机启动	chkconfig –list systemctl	systemctl list-units –type=service

4.用三种脚本监控服务

举例
监控端口注意引用命令需要用$()把命令放在括号中
例如监控21vsftpd端口

关于端口监控的脚本方法
第一种方法
#!/bin/bash
a=$(netstat -lntup|grep vsftpd|awk -F ':' '{print $4}')
if [ $a -eq 21 ]
 then
    echo 'vsftpd启动了'
 else [ $a -ge 21 ]
    echo 'vsftpd停止运行'
fi
第二种方法
#!/bin/bash
a=$(systemctl status vsftpd.service|awk 'NR==3 {print $3}')
if [ $a == '(running)' ]
 then       
    echo 'vsftpd正在运行'
 else [ $a == '(dead)' ]
    echo 'vsftpd停止运行'     
fi  
第三种方法
#!/bin/bash
a=$(systemctl status vsftpd.service|awk 'NR==3 {print $3}')
case $a in
\(running\))
echo 'vsftpd正在运行'
;;          
\(dead\))   
echo 'vsftp已停止运行'
;;
esac