理论基础：
User - > web ->nginx ->tomcat1 ->*.jsp
80 8080
↓ -> tomcat2
html -> tomcat3
用户通过web访问网页，默认访问的是80端口，即访问nginx。由于nginx只支持静态网页，如果用户访问的是类似*.jsp的动态网页，需要通过应用服务器tomcat先进行处理。tomcat相当与一个媒介，将动态网页经过处理之后交给nginx，最终返回给用户。
nginx后端的tomcat可以实现负载均衡，但是为了防止用户在访问过程出现类似下列情况：
访问登录页面时,帐号密码输入完成后，按下一步后马上又弹出一个登录界面
需要给nginx添加sticky模块，使得对于来自同一个用户的请求始终交给同一个tomcat处理
192.168.0.1 -> tomcat1
192.168.0.2 ->tomcat2 根据IP进行负载均衡
为了防止当用户在访问注册页面时，当用户填写注册信息到一半时，服务器宕机，当用户按“下一步”之后，用户之前提交的资料全部消失了，需要结合memcached来解决此问题。
nginx
|
T1 T2
| \ / |
| \/ |
| /\ |
| / \ |
M1 M2
交叉式存储，完美解决单点故障的问题
1号机子上有两个服务 T1和 M1
2号机子上有两个服务 T2 和 M2
默认的T1的数据往M2中存，T2的数据往M1中存，防止单点故障。
当T1服务挂掉之后，由T2接管，T2从M2中取得之前T1存在M2上的数据,之后提交的数据继续往M2上存（注：如果此时开启了另一个请求由T2接管，数据默认的往M1上存，而不是M2）；
接着如果连M2也挂掉了，但是由于T2是正常工作的，T2会将M2上所有的数据取出，并存到M1中，使得用户提交的数据仍然存在，不会丢失。
当1号机子挂掉后，T2存在M1上的数据将丢失
配置：
系统环境: rhel6 x86_64 iptables and selinux disabled
主机: n1:192.168.122.185:nginx tomcat memcached server85.example.com
n2:192.168.122.117:tomcat memcached server17.example.com
相关网址: rpm.pbone.net tomcat.apache.org
所需的包：memcache-2.2.5.tgz memcached-1.4.15.tar.gz libevent-devel-1.4.13-4.el6.x86_64.rpm libevent-doc-1.4.13-4.el6.noarch.rpm libevent-headers-1.4.13-4.el6.noarch.rpm webbench-1.5.tar.gz jdk-6u32-linux-x64.bin apache-tomcat-7.0.37.tar.gznginx-sticky-module-1.0.tar.gz asm-3.2.jar kryo-1.04.jar kryo-serializers-0.10.jar memcached-session-manager-1.6.3.jar memcached-session-manager-tc7-1.6.3.jar minlog-1.2.jar msm-kryo-serializer-1.6.3.jar reflectasm-1.01.jar spymemcached-2.7.3.jar
1.安装memcached
[root@server85 kernel]# tar zxf memcache-2.2.5.tgz
[root@server85 kernel]# cd memcache-2.2.5
[root@server85 memcache-2.2.5]# phpize
[root@server85 memcache-2.2.5]# ./configure
[root@server85 memcache-2.2.5]# make && make install
[root@server85 memcache-2.2.5]# vim /usr/local/lnmp/php/etc/php.ini
extension=memcache.so
[root@server85 memcache-2.2.5]# /etc/init.d/php-fpm reload
[root@server85 kernel]# tar zxf memcached-1.4.15.tar.gz
[root@server85 kernel]# cd memcached-1.4.15
[root@server85 memcached-1.4.15]# ./configure
此时会出现以下错误:
checking for libevent directory... configure: error: libevent is required. You can get it from http://www.monkey.org/~provos/libevent/
解决方法如下:
[root@server85 memcached-1.4.15]# yum install libevent
[root@server85 kernel]# rpm -ivh libevent-*
注：libevent-*包含:libevent-devel-1.4.13-4.el6.x86_64.rpm libevent-doc-1.4.13-4.el6.noarch.rpm libevent-headers-1.4.13-4.el6.noarch.rpm
[root@server85 memcached-1.4.15]# make && make install
[root@server85 ~]# memcached -m 50M -d -u root （若不制定大小默认64M,每次最大不超过2G)
[root@server85 ~]# ps ax
6106 ? Ssl 0:00 memcached -m 50M -d -u root
[root@server85 ~]# netstat -antple
tcp 0 0 0.0.0.0:11211 0.0.0.0:* LISTEN 0 12791 6106/memcached
出现类似上方的内容表示安装成功.
[root@server85 kernel]# cd memcache-2.2.5/
[root@server85 memcache-2.2.5]# cp memcache.php /usr/local/lnmp/nginx/html/
[root@server85 memcache-2.2.5]# vim /usr/local/lnmp/nginx/html/memcache.php
define('ADMIN_PASSWORD','westos'); // Admin Password
#$MEMCACHE_SERVERS[] = 'mymemcache-server1:11211';
$MEMCACHE_SERVERS[] = '192.168.122.185:11211';
[root@server85 memcache-2.2.5]# nginx -s reload
访问server85.example.com/memcache.php:
进行压力测试:
[root@server85 kernel]# tar zxf webbench-1.5.tar.gz
[root@server85 kernel]# cd webbench-1.5
[root@server85 webbench-1.5]# make
此时会出现以下错误:
/bin/sh: ctags: command not found
解决方法如下:
[root@server85 webbench-1.5]# yum install ctags -y
[root@server85 webbench-1.5]# make clean
[root@server85 webbench-1.5]# make install
[root@server85 ~]# webbench -c 500 -t 10 http://192.168.122.185/memcache.php
Webbench - Simple Web Benchmark 1.5
Copyright (c) Radim Kolar 1997-2004, GPL Open Source Software.
Benchmarking: GET http://server85.example.com/memcache.php
500 clients, running 10 sec.
Speed=20442 pages/min, 102477 bytes/sec.
Requests: 3407 susceed, 0 failed.
或者访问server85.example.com/status:
2.安装tomcat
[root@server85 kernel]# chmod +x jdk-6u32-linux-x64.bin
[root@server85 kernel]# ./jdk-6u32-linux-x64.bin
[root@server85 kernel]# mv jdk1.6.0_32/ /usr/local/jdk
[root@server85 kernel]# vim /etc/profile
export JAVA_HOME=/usr/local/jdk
export CLASSPATH=:$JAVA_HOME/lib
export PATH=$PATH:$JAVA_HOME/bin
[root@server85 kernel]# source /etc/profile
执行echo $PATH能看到/usr/local/jdk/bin说明已生效.
[root@server85 ~]# vim test.java
public class test{
public static void main(String[] agre) {
System.out.println("Hello World!");
}
}
[root@server85 ~]# javac test.java
[root@server85 ~]# java test
打印出Hello World!说明安装成功!
[root@server85 kernel]# tar zxf apache-tomcat-7.0.37.tar.gz -C /usr/local/
[root@server85 kernel]# cd /usr/local/
[root@server85 local]# mv apache-tomcat-7.0.37/ tomcat
[root@server85 local]# cd tomcat/bin/
[root@server85 bin]# ./startup.sh
[root@server85 bin]# netstat -antple
tcp 0 0 :::8080 :::* LISTEN 0 57982 7465/java
查看到8080端口说明启动成功.
访问server85.example.com:8080出现如下页面说明tomcat正常.
[root@server85 bin]# cd /usr/local/tomcat/webapps/ROOT/
[root@server85 ROOT]# vim test.jsp
the time is: <%=new java.util.Date() %>
访问server85.example.com:8080/test.jsp出现如下页面为正常.
[root@server85 ROOT]# vim /usr/local/lnmp/nginx/conf/nginx.conf
location ~ \.jsp$ {
proxy_pass http://127.0.0.1:8080;
} (访问*.jsp时候交给8080端口处理)
[root@server85 ROOT]# nginx -s reload
以下步骤在server85上实施：
[root@server85 kernel]# tar zxf nginx-sticky-module-1.0.tar.gz
[root@server85 kernel]# tar zxf nginx-1.2.7.tar.gz
[root@server85 kernel]# cd nginx-1.2.7
[root@server85 nginx-1.2.7]# vim src/core/nginx.h
#define NGINX_VER "nginx"
[root@server85 nginx-1.2.7]# vim auto/cc/gcc
# debug
#CFLAGS="$CFLAGS -g"
[root@server85 nginx-1.2.7]# ./configure --prefix=/usr/local/lnmp/nginx/ --with-http_ssl_module --with-http_stub_status_module –add-module=/root/kernel/nginx-sticky-module-1.0
[root@server85 nginx-1.2.7]# make && make install
[root@server85 nginx-1.2.7]# vim /usr/local/lnmp/nginx/conf/nginx.conf
http {
upstream koen{
sticky;
server 192.168.122.185:8080;
server 192.168.122.117:8080;
}
server {
listen 80;
server_name server85.example.com;
location ~ \.jsp$ {
proxy_pass http://koen;
}
}
}
[root@server85 nginx-1.2.7]# nginx -s stop
[root@server85 nginx-1.2.7]# nginx
[root@server85 nginx-1.2.7]# memcached -d -u root
[root@server85 nginx-1.2.7]# cd /usr/local/tomcat/webapps/ROOT/
[root@server85 ROOT]# vim test.jsp
<%@ page contentType="text/html; charset=GBK" %>
<%@ page import="java.util.*" %>
<html><head><title>Cluster App Test</title></head>
<body>
Server Info:
<%
out.println(request.getLocalAddr() + " : " + request.getLocalPort()+"<br>");%>
<%
out.println("<br> ID " + session.getId()+"<br>");
String dataName = request.getParameter("dataName");
if (dataName != null && dataName.length() > 0) {
String dataValue = request.getParameter("dataValue");
session.setAttribute(dataName, dataValue);
}
out.print("<b>Session list</b>");
Enumeration e = session.getAttributeNames();
while (e.hasMoreElements()) {
String name = (String)e.nextElement();
String value = session.getAttribute(name).toString();
out.println( name + " = " + value+"<br>");
System.out.println( name + " = " + value);
}
%>
<form action="test.jsp" method="POST">
name:<input type=text size=20 name="dataName">
<br>
key:<input type=text size=20 name="dataValue">
<br>
<input type=submit>
</form>
</body>
</html>
[root@server85 ROOT]# cd /usr/local/tomcat/lib/
把如下软件包放置在该目录下：
asm-3.2.jar
kryo-1.04.jar
kryo-serializers-0.10.jar
memcached-session-manager-1.6.3.jar
memcached-session-manager-tc7-1.6.3.jar
minlog-1.2.jar
msm-kryo-serializer-1.6.3.jar
reflectasm-1.01.jar
spymemcached-2.7.3.jar
[root@server85 lib]# vim /usr/local/tomcat/conf/context.xml
<Context>
<Manager className="de.javakaffee.web.msm.MemcachedBackupSessionManager"
memcachedNodes="n1:192.168.122.185:11211,n2:192.168.122.117:11211"
failoverNodes="n1"
requestUriIgnorePattern=".*\.(ico|png|gif|jpg|css|js)$" transcoderFactoryClass="de.javakaffee.web.msm.serializer.kryo.KryoTranscoderFactory"
/>
</Context>
[root@server85 lib]# /usr/local/tomcat/bin/shutdown.sh
[root@server85 lib]# /usr/local/tomcat/bin/startup.sh
以下步骤在server17上实施：
[root@server17 ~]# memcached -d -u root
[root@server17 ~]# cd /usr/local/tomcat/webapps/ROOT/
[root@server17 ROOT]# vim test.jsp
<%@ page contentType="text/html; charset=GBK" %>
<%@ page import="java.util.*" %>
<html><head><title>Cluster App Test</title></head>
<body>
Server Info:
<%
out.println(request.getLocalAddr() + " : " + request.getLocalPort()+"<br>");%>
<%
out.println("<br> ID " + session.getId()+"<br>");
String dataName = request.getParameter("dataName");
if (dataName != null && dataName.length() > 0) {
String dataValue = request.getParameter("dataValue");
session.setAttribute(dataName, dataValue);
}
out.print("<b>Session list</b>");
Enumeration e = session.getAttributeNames();
while (e.hasMoreElements()) {
String name = (String)e.nextElement();
String value = session.getAttribute(name).toString();
out.println( name + " = " + value+"<br>");
System.out.println( name + " = " + value);
}
%>
<form action="test.jsp" method="POST">
name:<input type=text size=20 name="dataName">
<br>
key:<input type=text size=20 name="dataValue">
<br>
<input type=submit>
</form>
</body>
</html>
[root@server17 ROOT]# cd /usr/local/tomcat/lib/
把如下软件包放置在该目录下：
asm-3.2.jar
kryo-1.04.jar
kryo-serializers-0.10.jar
memcached-session-manager-1.6.3.jar
memcached-session-manager-tc7-1.6.3.jar
minlog-1.2.jar
msm-kryo-serializer-1.6.3.jar
reflectasm-1.01.jar
spymemcached-2.7.3.jar
[root@server17 lib]# vim /usr/local/tomcat/conf/context.xml
<Context>
<Manager className="de.javakaffee.web.msm.MemcachedBackupSessionManager"
memcachedNodes="n1:192.168.122.185:11211,n2:192.168.122.117:11211"
failoverNodes="n2"
requestUriIgnorePattern=".*\.(ico|png|gif|jpg|css|js)$" transcoderFactoryClass="de.javakaffee.web.msm.serializer.kryo.KryoTranscoderFactory"
/>
</Context>
[root@server17 bin]# /usr/local/tomcat/bin/shutdown.sh
[root@server17 bin]# /usr/local/tomcat/bin/startup.sh
测试：
1.存储数据:
2.把server85上的m1宕掉然后存入user3
3.重置server85上的m1，存user4
4.把server17上的m2宕掉，存user5
5.重置server17上的m2,存user6
6.把server17上的tomcat关闭，存user7
测试完毕！！！
