Linux下tomcat守护程序，避免tomcat中断或内存溢出

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=$PATH:/sbin:/bin:/usr/sbin:/usr/bin; tomcat_port=":8080 "; tomcat_base_dir="/home/test/tomcat-5.0.28"; check_page_url=http://127.0.0.1:8080/testweb/test.jsp; pid_filt_pattern="tomcat"; guarder_dir="/home/test"; log_file="/home/test/tomcat_run_log.log"; d=$(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()); %>