练习

1、判断当前磁盘剩余空间是否有20G，如果小于20G，则将报警邮件发送给管理员，每天检查一次磁盘剩余空间。
2、判断web服务是否运行（1、查看进程的方式判断该程序是否运行2、通过查看端口的方式判断该程序是否运行），如果没有运行，则启动该服务。
3、使用curl命令访问第二题的web服务，看能否正常访问，如果能正常访问，则返回web server is running；如果不能正常访问，返回12状态码。

1、判断当前磁盘剩余空间是否有20G，如果小于20G，则将报警邮件发送给管理员，每天检查一次磁盘剩余空间。

[root@redhat9 shellwenjian]# vim ade.sh
#!/bin/bash
mb=`df -m / | awk 'NR==2{print $4}'`
gb=$[mb/1024]
if [ "$gb" -lt 20 ]
then
        echo "您最近的磁盘空间已经小于20G，请及时查看！" |  mail -s "WORNING!" root@localhost
fi
[root@redhat9 shellwenjian]# cat /etc/crontab
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
 
# For details see man 4 crontabs
 
# Example of job definition:
# .---------------- minute (0 - 59)
# |  .------------- hour (0 - 23)
# |  |  .---------- day of month (1 - 31)
# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# |  |  |  |  |
# *  *  *  *  * user-name  command to be executed
0 0 * * * root /shellwenjian/ade.sh

2、判断web服务是否运行（1、查看进程的方式判断该程序是否运行2、通过查看端口的方式判断该程序是否运行），如果没有运行，则启动该服务。 

 

#!/bin/bash

rpm_http=`rpm -qa httpd |wc -l`
if [ $rpm_http -ge 1 ]
then
        systemctl start httpd;
else
        yum install -y httpd;
        systemctl start httpd;
fi
rpm_firewall=`rpm -qa firewalld |wc -l`
if [ $rpm_firewall -ge 1 ]
then
        systemctl start firewalld;
        firewall-cmd --add-service=http --permanent;
else
        yum install -y firewalld;
        systemctl start firewalld;
        firewall-cmd --add-service=http --permanent;
fi
ps_ef=`ps -ef | grep "httpd" | wc -l`
port_web=`ss -lntup | grep -w "80" |  wc -l`
if [ $ps_ef -ge 2 ] && [ $port_web -ge 2 ]
then
        echo "web服务已运行!"
else
        echo "稍后为您开启web服务！"
        systemctl start httpd;
fi
##
#ps_ef=`ps -ef | grep "httpd" | grep -v grep  | wc -l`
#port_web=`ss -lntup | grep -w "80" | grep -v grep | wc -l`
#if [ $ps_ef -ge 1 ] && [ $port_web -ge 1 ]
#then
#        echo "web服务已运行!"
#else
#        echo "稍后为您开启web服务！"
#        systemctl start httpd;
#fi 

测试 

[root@redhat9 shellwenjian]# yum remove httpd firewalld
[root@redhat9 shellwenjian]# bash httpdfirewall.sh
Complete!
Warning: ALREADY_ENABLED: http
success
web服务已运行!
[root@redhat9 shellwenjian]# systemctl status httpd firewalld.service          #状态
● httpd.service - The Apache HTTP Server
     Loaded: loaded (/usr/lib/systemd/system/httpd.service; disabled; vendor preset: disabled)
     Active: active (running) since Wed 2023-04-05 18:21:11 CST; 1min 7s ago
       Docs: man:httpd.service(8)
   Main PID: 58339 (httpd)
     Status: "Total requests: 0; Idle/Busy workers 100/0;Requests/sec: 0; Bytes served/sec:   0 B/sec"
      Tasks: 213 (limit: 64977)
     Memory: 33.8M
        CPU: 104ms
     CGroup: /system.slice/httpd.service
             ├─58339 /usr/sbin/httpd -DFOREGROUND
             ├─58341 /usr/sbin/httpd -DFOREGROUND
             ├─58342 /usr/sbin/httpd -DFOREGROUND
             ├─58343 /usr/sbin/httpd -DFOREGROUND
             └─58476 /usr/sbin/httpd -DFOREGROUND
 
Apr 05 18:21:09 redhat9 systemd[1]: Starting The Apache HTTP Server...
Apr 05 18:21:11 redhat9 httpd[58339]: Server configured, listening on: port 443, port 80
Apr 05 18:21:11 redhat9 systemd[1]: Started The Apache HTTP Server.
 
● firewalld.service - firewalld - dynamic firewall daemon
     Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
     Active: active (running) since Wed 2023-04-05 18:21:14 CST; 1min 5s ago
       Docs: man:firewalld(1)
   Main PID: 59040 (firewalld)
      Tasks: 2 (limit: 64977)
     Memory: 26.0M
        CPU: 357ms
     CGroup: /system.slice/firewalld.service
             └─59040 /usr/bin/python3 -s /usr/sbin/firewalld --nofork --nopid
 
Apr 05 18:21:14 redhat9 systemd[1]: Starting firewalld - dynamic firewall daemon...
Apr 05 18:21:14 redhat9 systemd[1]: Started firewalld - dynamic firewall daemon.
Apr 05 18:21:14 redhat9 firewalld[59040]: WARNING: ALREADY_ENABLED: http
[root@redhat9 shellwenjian]# firewall-cmd --list-services    #firewalld
cockpit dhcpv6-client http ssh
[root@redhat9 shellwenjian]# curl 192.168.2.135         #httpd
<!DOCTYPE html>
<html>
        <head>
                <meta charset="utf-8">
                <title></title>
                <style>
                        .openlab{
                                font-size: 66px;
                                color: red;
                                text-align: center;
                        }
                </style>
        </head>
        <body>
                <div class="openlab">welcome to openlab!!!</div>
        </body>
</html> 

3、使用curl命令访问第二题的web服务，看能否正常访问，如果能正常访问，则返回web server is running；如果不能正常访问，返回12状态码。

curl http://localhost &> /dev/null
if [ $? -eq 0 ];then
          echo web server is running
else
          exit 12

fi