检测服务是否存在，不存在等待N次从启

server_name ：服务名,ps -ef里面查看的服务名

max_num:检测多少次失败后从启

logfile:日志存放文件

默认是检测失败了3次就会

#!/bin/bash
server_name=nginx
max_num=3
logfile=/tmp/${server_name}_check.log

function check(){
        pid_number=`ps -ef |grep ${server_name}|grep -v grep|wc -l`
        if [ $pid_number -eq 0 ];then
                return 1
        else
                return 0
        fi
}

function start_server(){
        systemctl start nginx
}

for num in `seq ${max_num}`;do
        if check;then
                echo "`date`  ${server_name}  is ok">>${logfile}
                exit 255
        else
                echo "`date`  ${server_name}  is error">>${logfile}
                if [ ${num} -eq 3 ];then
                        start_server
                        echo "`date`  ${server_name}  is start">>${logfile}
                fi
                sleep 3
        fi
done
~      

运行日志截图