这一两天现场实施的同事,发现系统的tomcat会因为内存溢出的情况出现假死的情况。现场的同事一时查不出问题,最后一招了写个脚本监控一下。
1 使用环境
操作系统:CentOS 4.8
JDK版本:j2sdk1.4.2
Tomcat版本:tomcat-5.0.28
2 监控脚本
- #!/bin/bash
- #
- # Keep watch at tomcat's status,
- # automatically restart it if it dead or out of memory.
-
- export PATH=$PATH:/sbin:/bin:/usr/sbin:/usr/bin;
- tomcat_port=":8080 ";
- tomcat_base_dir="/home/test/tomcat-5.0.28";
- check_page_url=
- pid_filt_pattern="tomcat";
- guarder_dir="/home/test";
- log_file="/home/test/tomcat_run_log.log";
- d=$(date +%F" "%T);
-
- # init the log file
- touch ${log_file}
-
- do_restart_tomcat() {
- # first, try to shutdown it anyway!
- ${tomcat_base_dir}/bin/shutdown.sh
-
- # second, check if the tomcat pid still exist, if yes then kill it!
- if ps -ef | grep ${pid_filt_pattern} | grep -v grep
- then
- kill -9 $(ps -ef | grep ${pid_filt_pattern} | grep -v grep | awk '{print $2}')
- fi
-
- # run start tomcat
- ${tomcat_base_dir}/bin/startup.sh
- echo "$d success restart tomcat, the new pid is " >> ${log_file}
- ps -ef | grep ${pid_filt_pattern} | grep -v grep | awk '{print $2}' >> ${log_file}
- echo >> ${log_file}
- }
-
- # first, check if the tomcat si listen on the port
- if netstat -ln | grep ${tomcat_port}
- then
- # init the check result file
- if [ -e ${guarder_dir}/checkResult.tmp ]
- then
- cat /dev/null > ${guarder_dir}/checkResult.tmp
- else
- touch ${guarder_dir}/checkResult.tmp
- fi
-
- # try to get the check result
- wget -b -o wget.log -O ${guarder_dir}/checkResult.tmp ${check_page_url}
-
- # wait 5 second to let the get check result job done.
- sleep 5
-
- # check the result
- workflag=$(cat ${guarder_dir}/checkResult.tmp |grep ServerStillWorking)
- memoryflag=$(cat ${guarder_dir}/checkResult.tmp |grep LessOfMemory)
-
- if [ "$workflag" == "" ]; then
- echo "$d can not found [ServerStillWorking] in the check result, try to restart tomcat ......" >> ${log_file}
- do_restart_tomcat
- elif [ "$memoryflag" == "" ]; then
- echo "$d can not found [LessOfMemory] in the check result, the tomcat server may out of memory, try to restart it ......" >> ${log_file}
- do_restart_tomcat
- fi
- else
- echo "$d found the tomcat not listen on ${tomcat_port}, try to restart it ......" >> ${log_file}
- do_restart_tomcat
- fi
3 加入定时任务crontab
3.1 编辑任务
[test@cent4 ~]$ crontab -e
进入编辑crontab的vi界面,按i键进入插入模式,将如下代码复制到输入界面
*/20 * * * * "/home/test/deamon2tomcat.sh" > /dev/null 2>&1
注:每20分钟检查一次(可修改),加“> /dev/null 2>&1 ”是为了不让它发邮件。
3.2 保存退出
按Esc键进入命令模式,输入wq,回车后则会保存退出。
3.3 查看任务
最后查看任务,确认是否编辑成功。
[test@cent4 ~]$ crontab -l
*/20 * * * * "/home/test/deamon2tomcat.sh" > /dev/null 2>&1
4 jsp的内容
- <%@ page contentType="text/html;charset=GBK"%>
- <%@ page import="java.util.*"%>
- <%
- out.println("<br>");
- out.println("<center><h1>");
- out.println("The Web Server is Running!<br><br>");
- out.println("h1>center>");
- out.println("<br><br>");
- out.println("ServerStillWorking");//标记字符!
-
- long maxMemory = Runtime.getRuntime().maxMemory() / 1024 / 1024; //java虚拟机能取得的最大内存
- long totalMemory = Runtime.getRuntime().totalMemory() / 1024 / 1024; //java虚拟机当前取得的内存大小
- long freeMemory = Runtime.getRuntime().freeMemory() / 1024 / 1024; //java虚拟机所占用的内存中的空闲部分
- long usedMemory = totalMemory - freeMemory; //java虚拟机当前实际使用的内存大小
- out.println("<br><br>Max Momery is: " + maxMemory + "M");
- out.println("<br>Total Memory is: " + totalMemory + "M");
- out.println("<br>Used Memory is: " + usedMemory + "M");
- out.println("<br>Free Memory is: " + freeMemory + "M");
- out.println("<br><br>");
-
- if (usedMemory < maxMemory) {
- out.println("LessOfMemory"); //标记字符!
- } else {
- out.println("OutOfMemory"); //标记字符!
- }
- out.println("<br><br>");
- out.println(new java.util.Date());
- out.println("<br>");
- out.println(TimeZone.getDefault().getDisplayName());
- %>