#!/bin/bash
pgrep -x mysqld &> /dev/null
if [ $? -ne 0 ]
then
echo "At time: `date` :MySQL  is stop .">> /var/log/mysql_messages
service mysql start
#echo "At time: `date` :MySQL server is stop."
else
echo "MySQL server is running ."
fi

将上述脚本保存到mysql.sh中，上传到服务器，运行该脚本可以发现输出数据库服务正在运行

# sh mysql.sh
MySQL server is running 

每隔一定时间自动运行脚本

Centos7-mqtt消息中间件mosquitto的安装和配置

#!/bin/bash
pgrep -x mysqld &> /dev/null
 
if [ $? -ne 0 ]
 
then
 
mosquitto_pub -t mysql_status -m "Failed"
 
service mysql start
#echo "At time: `date` :MySQL server is stop."
 
else
 
mosquitto_pub -t mysql_status -m "Running"
 
fi

import paho.mqtt.client as mqtt
# The callback for when the client receives a CONNACK response from the server.
def on_connect(client, userdata, flags, rc):
    print("Connected with result code "+str(rc))
    # Subscribing in on_connect() means that if we lose the connection and
    # reconnect then subscriptions will be renewed.
    client.subscribe("mysql_status")
    #订阅，第一个参数是订阅的主题
# The callback for when a PUBLISH message is received from the server.
def on_message(client, userdata, msg):
    print(msg.topic+" "+str(msg.payload))
client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message
client.connect("主机名或ip", 1883, 60)
#第一个参数为主机名，及Mosquitto所在服务器，第二个参数是端口
# Blocking call that processes network traffic, dispatches callbacks and
# handles reconnecting.
# Other loop*() functions are available that give a threaded interface and a
# manual interface.
client.loop_forever()