本文使用到nginx1.5.4、tomcat6.0.35。
1、配置nginx
~/conf/nginx.conf
#user guzicheng;
worker_processes 1;
error_log logs/error.log;
#error_log logs/error.log notice;
#error_log logs/error.log info;
#pid logs/nginx.pid;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
#log_format main '$remote_addr - $remote_user [$time_local] "$request" '
# '$status $body_bytes_sent "$http_referer" '
# '"$http_user_agent" "$http_x_forwarded_for"';
#access_log logs/access.log main;
sendfile on;
#tcp_nopush on;
#keepalive_timeout 0;
keepalive_timeout 65;
gzip on;
upstream localhost {
server 127.0.0.1:8081;
server 127.0.0.1:8082;
}
server {
listen 80;
server_name localhost;
charset utf-8;
#access_log logs/host.access.log main;
location / {
root html;
index index.html index.htm;
proxy_pass http://localhost;
}
#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
# proxy the PHP scripts to Apache listening on 127.0.0.1:80
#
#location ~ \.php$ {
# proxy_pass http://127.0.0.1;
#}
# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
#location ~ \.php$ {
# root html;
# fastcgi_pass 127.0.0.1:9000;
# fastcgi_index index.php;
# fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;
# include fastcgi_params;
#}
# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
#location ~ /\.ht {
# deny all;
#}
}
# another virtual host using mix of IP-, name-, and port-based configuration
#
#server {
# listen 8000;
# listen somename:8080;
# server_name somename alias another.alias;
# location / {
# root html;
# index index.html index.htm;
# }
#}
# HTTPS server
#
#server {
# listen 443 ssl;
# server_name localhost;
# ssl_certificate cert.pem;
# ssl_certificate_key cert.key;
# ssl_session_cache shared:SSL:1m;
# ssl_session_timeout 5m;
# ssl_ciphers HIGH:!aNULL:!MD5;
# ssl_prefer_server_ciphers on;
# location / {
# root html;
# index index.html index.htm;
# }
#}
}
主要修改内容:
……
http{
upstream localhost {
server 127.0.0.1:8081;
server 127.0.0.1:8082;
}
server {
listen 80;
server_name localhost;
……
location / {
……
proxy_pass http://localhost;
}
……
}
}
……
测试修改内容:
/usr/local/nginx/sbin/nginx -t
启动nginx
/usr/local/nginx/sbin/nginx
在浏览器中输入http://localhost,测试nginx是否启动成功。
2、配置Tomcat
分别打开tomcat1和tomcat2下conf中server.xml。
注意端口号不要重复
<Server port="8005" shutdown="SHUTDOWN">
...
<Connector port="8081" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443" />
...
<!-- Define an AJP 1.3 Connector on port 8009 -->
<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />
修改<Engine>节点
<Engine name="Catalina" defaultHost="localhost" jvmRoute="tomcat1">
<Engine name="Catalina" defaultHost="localhost"jvmRoute="tomcat2">
(注:至此,完成了tomcat负载均衡。下面进行session同步配置,通过tomcat自身实现session同步。)
去掉<Cluster>节点的注释
<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/>
打开web.xml,在</web-app>节点前添加:
<distributable/>
a、在tomcat下创建test工程,分别建立测试页面index.jsp
tomcat1:
SessionID:<%=session.getId()%>
<BR>
SessionIP:<%=request.getServerName()%>
<BR>
SessionPort:<%=request.getServerPort()%>
<BR>
<%
String name=(String)session.getAttribute("name");
if(name==null||name.equals("")){
session.setAttribute("name","Hello Host1!");
out.println(session.getAttribute("name"));
}else{
out.println(name);
}
%>
<BR>
This is Tomcat Server 111111!
tomcat2:
SessionID:<%=session.getId()%>
<BR>
SessionIP:<%=request.getServerName()%>
<BR>
SessionPort:<%=request.getServerPort()%>
<BR>
<%
String name=(String)session.getAttribute("name");
if(name==null||name.equals("")){
session.setAttribute("name","Hello Host2!");
out.println(session.getAttribute("name"));
}else{
out.println(name);
}
%>
<BR>
This is Tomcat Server 222222!
b、启动tomcat1、tomcat2、nginx
c、在浏览器中输入http://localhost/test/index.jsp
如果SessionID、CreateTime、“Hello Host”不变,最后易行“This is Tomcat Server ...”不停变化,说明session复制成功。
这种方式实现的session同步存在缺陷:当一个节点的session数据发生变化,要把整个session数据全部序列化,广播给其他节点,造成大量网络通信,导致网络阻塞。下面一篇介绍通过terracotta实现tomcat集群的session同步。
参考:
http://www.blogjava.net/Alpha/archive/2011/06/21/352745.html
http://blog.youkuaiyun.com/shimiso/article/details/8979044
http://blog.163.com/comfort_122/blog/static/48904409201131145149530