问题描述：监控MYSQL服务是否正常启动，如果未正常启动，就启动MYSQL
判断mysql的方法：
1)端口判断
[root@localhost ~]# netstat -lntup | grep 3306
tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 2288/mysqld
2)进程判断
[root@localhost ~]# ps -ef | grep mysqld
mysql 2071 1 0 11:32 ? 00:00:00 /bin/sh /usr/bin/mysqld_safe –basedir=/usr
mysql 2288 2071 0 11:32 ? 00:00:24 /usr/libexec/mysqld –basedir=/usr –datadir=/var/lib/mysql –plugin-dir=/usr/lib64/mysql/plugin –log-error=/var/log/mariadb/mariadb.log –pid-file=/var/run/mariadb/mariadb.pid –socket=/var/lib/mysql/mysql.sock
root 10097 6962 0 17:27 pts/1 00:00:00 grep –color=auto mysqld
3)返回值判断
[root@localhost ~]# mysql -uroot -proot -e “select version();” &>/dev/null
[root@localhost ~]# echo $?
0
法一：实现思路是过滤出MYSQL端口3306进行判断：
#!/bin/bash
port=`netstat -lnt|grep 3306|wc-l`
if [ $port -ne 1 ]
then
/etc/init.d/mysql start
else
echo “MySQL is running.”
fi
执行结果：
[root@localhost ~]# sh mysql1.sh
MySQL is running.
法二：实现思路是通过MYSQL进程进行判断：
#!/bin/bash
portcess=`ps -ef|grep mysql|grep -v grep|wc -l`
if [ $portcess -ne 2 ]
then
/etc/init.d/mysqld start
else
echo “MySQL is running.”
fi
执行结果：
[root@localhost ~]# sh mysql1.sh
MySQL is running.
注意：过滤的字符串‘mysql’不要在脚本名字出现，如果出现则不准
法三：实现思路是通过web连接返回值判断：
#!/bin/bash
mysql -uroot -proot -e “select version();” &>/dev/null
if [ $? -ne 0 ]
then
/etc/init.d/mysqld start
else
echo “MySQL is running.”
fi
执行结果：
[root@localhost ~]# sh mysql1.sh
MySQL is running.
摘自：http://blog.51cto.com/baishuchao/1942148