redis

目录



I.redis介绍

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redis是一个key-value存储系统。和Memcached类似,它支持存储的value类型相对更多,包括string(字符串)、list(链表)、set(集合)、zset(sorted set--有序集合)和hash(哈希类型)。与memcached一样,为了保证效率,数据都是缓存在内存中。区别的是redis会周期性的把更新的数据写入磁盘或者把修改操作写入追加的记录文件,并且在此基础上实现master-slave(主从)同步。

Redis 是一个高性能的key-value数据库。 redis的出现,很大程度补偿了memcached这类key/value存储的不足,在部分场合可以对关系数据库起到很好的补充作用。它提供了JavaC/C++C#PHPJavaScriptPerlObject-CPythonRuby等客户端,使用很方便。

i.单地比较RedisMemcached的区别

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基本上有以下3点

  • 1、Redis不仅仅支持简单的k/v类型的数据,同时还提供listsetzsethash等数据结构的存储。
  • 2、Redis支持数据的备份,即master-slave模式的数据备份。
  • 3、Redis支持数据的持久化,可以将内存中的数据保持在磁盘中,重启的时候可以再次加载进行使用。

在Redis中,并不是所有的数据都一直存储在内存中的。这是和Memcached相比一个最大的区别。Redis只会缓存所有的key的信息,如果Redis发现内存的使用量超过了某一个阀值,将触发swap的操作,Redis根据swappability = age*log(size_in_memory)计算出哪些key对应的value需要swap到磁盘。然后再将这些key对应的value持久化到磁盘中,同时在内存中清除。这种特性使得Redis可以保持超过其机器本身内存大小的数据。当然,机器本身的内存必须要能够保持所有的key,因为这些数据是不会进行swap操作的。

当 从Redis中读取数据的时候,如果读取的key对应的value不在内存中,那么Redis就需要从swap文件中加载相应数据,然后再返回给请求方。

ii.memcachedredis的比较

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1.网络IO模型

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Memcached是多线程,非阻塞IO复用的网络模型,分为监听主线程和worker子线程,监听线程监听网络连接,接受请求后,将连接描述字pipe传递给worker线程,进行读写IO, 网络层使用libevent封装的事件库,多线程模型可以发挥多核作用。

Redis使用单线程的IO复用模型,自己封装了一个简单的AeEvent事件处理框架,主要实现了epollkqueueselect,对于单纯只有IO操作来说,单线程可以将速度优势发挥到最大,但是Redis也提供了一些简单的计算功能,比如排序、聚合等,对于这些操作,单线程模型实际会严重影响整体吞吐量,CPU计算过程中,整个IO调度都是被阻塞住的。

2.内存管理方面

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Memcached使用预分配的内存池的方式,使用slab和大小不同的chunk来管理内存,value根据大小选择合适的chunk存储。Redis使用现场申请内存的方式来存储数据。

3.存储方式及其它方面

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Memcached基本只支持简单的key-value存储,不支持持久化和复制等功能,Redis除key/value之外,还支持list,set,sorted set,hash等众多数据结构


II.如何保持session会话

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目前,为了使web能适应大规模的访问,需要实现应用的集群部署。集群最有效的方案就是负载均衡,而实现负载均衡用户每一个请求都有可能被分配到不固定的服务器上,这样我们首先要解决session的统一来保证无论用户的请求被转发到哪个服务器上都能保证用户的正常使用,即需要实现session的共享机制。

在集群系统下实现session统一的有如下几种方案

i.请求精确定位

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session sticky,例如基于访问iphash策略,即当前用户的请求都集中定位到一台服务器中,这样单台服务器保存了用户的session登录信息,如果宕机,则等同于单点部署,会丢失,会话不复制。

ii.session复制共享

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session replication,如tomcat自带session共享,主要是指集群环境下,多台应用服务器之间同步session,使session保持一致,对外透明。 如果其中一台服务器发生故障,根据负载均衡的原理,调度器会遍历寻找可用节点,分发请求,由于session已同步,故能保证用户的session信息不会丢失,会话复制,。

此方案的不足之处

必须在同一种中间件之间完成(如:tomcat-tomcat之间). session复制带来的性能损失会快速增加.特别是当session中保存了较大的对象,而且对象变化较快时, 性能下降更加显著,会消耗系统性能。这种特性使得web应用的水平扩展受到了限制。 Session内容通过广播同步给成员,会造成网络流量瓶颈,即便是内网瓶颈。在大并发下表现并不好

iii.基于cache DB缓存的session共享

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基于memcache/redis缓存的session 共享

即使用cacheDB存取session信息,应用服务器接受新请求将session信息保存在cache DB中,当应用服务器发生故障时,调度器会遍历寻找可用节点,分发请求,当应用服务器发现session不在本机内存时,则去cache DB中查找,如果找到则复制到本机,这样实现session共享和高可用。


III.nginx+tomcat+redis实现负载均衡、session共享

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i.实验环境

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主机 操作系统 IP地址

  • Nginx Centos7.2 192.168.31.141
  • Tomcat-1 192.168.31.83
  • Tomcat-2 192.168.31.250
  • Mysql 192.168.31.225
  • Redis 192.168.31.106

ii.实验拓扑

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在这个图中,nginx做为反向代理,实现静动分离,将客户动态请求根据权重随机分配给两台tomcat服务器,redis做为两台tomcat的共享session数据服务器,mysql做为两台tomcat的后端数据库。

iii.nginx安装配置

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使用Nginx作为Tomcat的负载平衡器,Tomcat的会话Session数据存储在Redis,能够实现零宕机的7x24效果。因为将会话存储在Redis中,因此Nginx就不必配置成stick粘贴某个Tomcat方式,这样才能真正实现后台多个Tomcat负载平衡。

1.安装nginx

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安装zlib-develpcre-devel等依赖包

[root@www ~]# yum -y install gcc gcc-c++ make libtool zlib zlib-devel pcre pcre-devel openssl openssl-devel

注: 结合proxyupstream模块实现后端web负载均衡 结合nginx默认自带的 ngx_http_proxy_module 模块 和ngx_http_upstream_module模块实现后端服务器的健康检查

创建nginx程序用户

[root@www ~]# useradd -s /sbin/nologin www

编译安装nginx

[root@www ~]# tar zxf nginx-1.10.2.tar.gz 
[root@www ~]# cd nginx-1.10.2/
[root@www nginx-1.10.2]# ./configure --prefix=/usr/local/nginx1.10 --user=www --group=www --with-http_stub_status_module --with-http_realip_module --with-http_ssl_module --with-http_gzip_static_module  --with-pcre  --with-http_flv_module
[root@www nginx-1.10.2]# make && make install

优化nginx程序的执行路径

[root@www nginx-1.10.2]# ln -s /usr/local/nginx1.10/sbin/nginx /usr/local/sbin/
[root@www nginx-1.10.2]# nginx -t
nginx: the configuration file /usr/local/nginx1.10/conf/nginx.conf syntax is ok
nginx: configuration file /usr/local/nginx1.10/conf/nginx.conf test is successful

2.编写nginx服务脚本

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脚本内容如下

[root@www ~]# cat /etc/init.d/nginx 
#!/bin/bash
# nginx Startup script for the Nginx HTTP Server
# chkconfig: - 85 15
# pidfile: /usr/local/nginx1.10/logs/nginx.pid
# config: /usr/local/nginx1.10/conf/nginx.conf
nginxd=/usr/local/nginx1.10/sbin/nginx
nginx_config=/usr/local/nginx1.10/conf/nginx.conf
nginx_pid=/usr/local/nginx1.10/logs/nginx.pid
RETVAL=0
prog="nginx"
# Source function library.
. /etc/rc.d/init.d/functions
# Start nginx daemons functions.
start() {
if [ -f $nginx_pid ] ; then
   echo "nginx already running...."
   exit 1
fi
   echo -n "Starting $prog: "
   $nginxd -c ${nginx_config}
   RETVAL=$?
   [ $RETVAL = 0 ] && touch /var/lock/subsys/nginx
}
# Stop nginx daemons functions.
stop() {
        echo -n "Stopping $prog: "
        $nginxd -s stop
        RETVAL=$?
        [ $RETVAL = 0 ] && rm -f /var/lock/subsys/nginx
}
# reload nginx service functions.
reload() {
    echo -n "Reloading $prog: "
    $nginxd -s reload
}
# status ngnx service functions
status() {
if [ -f $nginx_pid ] ; then
    echo  "$prog is running"
else
    echo  "$prog is stop"
fi
}
case "$1" in
start)
        start
        ;;
stop)
        stop
        ;;
reload)
        reload
        ;;
restart)
        stop
        start
        ;;
status)
        status
        ;;
*)
        echo "Usage: $prog {start|stop|restart|reload|status}"
        exit 1
        ;;
esac
[root@www ~]# chmod +x /etc/init.d/nginx
[root@www ~]# chkconfig --add nginx
[root@www ~]# chkconfig nginx on

3.配置nginx反向代理:反向代理+负载均衡+健康探测

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nginx.conf文件内容

[root@www ~]# cat /usr/local/nginx1.10/conf/nginx.conf
user  www www;
worker_processes  4;
worker_cpu_affinity 0001 0010 0100 1000;
error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;
worker_rlimit_nofile 10240;
pid        logs/nginx.pid;
events {
    use epoll;
    worker_connections  4096;
}
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;
    server_tokens off;
    sendfile        on;
    tcp_nopush     on;
    #keepalive_timeout  0;
    keepalive_timeout  65;
    #Compression Settings
    gzip on;
    gzip_comp_level 6;
    gzip_http_version 1.1;
    gzip_proxied any;
    gzip_min_length 1k;
    gzip_buffers 16 8k;
    gzip_types text/plain text/css text/javascript application/json application/javascript application/x-javascript application/xml;
    gzip_vary on;
    #end gzip
    # http_proxy Settings
    client_max_body_size   10m;
    client_body_buffer_size   128k;
    proxy_connect_timeout   75;
    proxy_send_timeout   75;
    proxy_read_timeout   75;
    proxy_buffer_size   4k;
    proxy_buffers   4 32k;
    proxy_busy_buffers_size   64k;
    proxy_temp_file_write_size  64k;
    #load balance Settings
    upstream backend_tomcat {
        server 192.168.31.83:8080 weight=1 max_fails=2 fail_timeout=10s;
        server 192.168.31.250:8080 weight=1 max_fails=2 fail_timeout=10s;
    }
    #virtual host Settings
    server {
        listen       80;
        server_name  www.benet.com;
        charset utf-8;
        location / {
            root html;
            index  index.jsp index.html index.htm;
        }
        location ~* \.(jsp|do)$ {
           proxy_pass  http://backend_tomcat;
           proxy_redirect off;
           proxy_set_header Host $host;
           proxy_set_header X-Real-IP $remote_addr;
           proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
           proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504;
        }
        location /nginx_status {
            stub_status on;
            access_log off;
            allow 192.168.31.0/24;
            deny all;
        }
    }
}

重启nginx服务,使修改生效

[root@www ~]# service  nginx restart

配置防火墙规测

[root@www ~]# firewall-cmd --permanent --add-port=80/tcp
success
[root@www ~]# firewall-cmd --reload 
success

iv.安装部署tomcat应用程序服务器

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tomcat-1tomcat-2节点上安装JDK

在安装tomcat之前必须先安装JDKJDK的全称是java development kit,是sun公司免费提供的java语言的软件开发工具包,其中包含java虚拟机(JVM),编写好的java源程序经过编译可形成java字节码,只要安装了JDK,就可以利用JVM解释这些字节码文件,从而保证了java的跨平台性。

1.安装JDK,配置java环境

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jdk-7u65-linux-x64.gz解压

[root@tomcat-1 ~]# tar zxf jdk-7u65-linux-x64.gz

将解压的jdk1.7.0_65目录移致动到/usr/local/下并重命名为java

[root@tomcat-1 ~]# mv jdk1.7.0_65/ /usr/local/java

1.2tomcat环境变量

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/etc/profile文件中添加内容如下

export JAVA_HOME=/usr/local/java
export PATH=$JAVA_HOME/bin:$PATH

通过source命令执行profile文件,使其生效。

[root@tomcat-1 ~]# source /etc/profile
[root@tomcat-1 ~]# echo $PATH
/usr/local/java/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin
按照相同方法在`tomcat-2`也安装`JDK`

1.3java version

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分别在在tomcat-1tomcat-2节点运行java -version命令查看java版本是否和之前安装的一致。

[root@tomcat-1 ~]# java -version
java version "1.7.0_65"
Java(TM) SE Runtime Environment (build 1.7.0_65-b17)
Java HotSpot(TM) 64-Bit Server VM (build 24.65-b04, mixed mode)

至此java环境已经配置完成

2.在tomcat-1tomcat-2节点安装配置tomcat

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解压apache-tomcat-7.0.54.tar.gz

[root@tomcat-1 ~]# tar zxf apache-tomcat-7.0.54.tar.gz

将解压生成的文件夹移动到/usr/local/下,并改名为tomcat7

[root@tomcat-1 ~]# mv apache-tomcat-7.0.54 /usr/local/tomcat7

2.1配置tomcat环境变量

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/etc/profile文件内容如下

export JAVA_HOME=/usr/local/java
export CATALINA_HOME=/usr/local/tomcat7
export PATH=$JAVA_HOME/bin:$CATALINA_HOME/bin:$PATH

通过source命令执行profile文件,使其生效

[root@tomcat-1 ~]# source /etc/profile
[root@tomcat-1 ~]# echo $PATH
/usr/local/java/bin:/usr/local/tomcat7/bin:/usr/local/java/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin

查看tomcat的版本信息

[root@tomcat-1 ~]# catalina.sh version
Using CATALINA_BASE:   /usr/local/tomcat7
Using CATALINA_HOME:   /usr/local/tomcat7
Using CATALINA_TMPDIR: /usr/local/tomcat7/temp
Using JRE_HOME:        /usr/local/java
Using CLASSPATH:       /usr/local/tomcat7/bin/bootstrap.jar:/usr/local/tomcat7/bin/tomcat-juli.jar
Server version: Apache Tomcat/7.0.54
Server built:   May 19 2014 10:26:15
Server number:  7.0.54.0
OS Name:        Linux
OS Version:     3.10.0-327.el7.x86_64
Architecture:   amd64
JVM Version:    1.7.0_65-b17
JVM Vendor:     Oracle Corporation

启动tomcat

[root@tomcat-1 ~]# /usr/local/tomcat7/bin/startup.sh 
Using CATALINA_BASE:   /usr/local/tomcat7
Using CATALINA_HOME:   /usr/local/tomcat7
Using CATALINA_TMPDIR: /usr/local/tomcat7/temp
Using JRE_HOME:        /usr/local/java
Using CLASSPATH:       /usr/local/tomcat7/bin/bootstrap.jar:/usr/local/tomcat7/bin/tomcat-juli.jar
Tomcat started.

Tomcat默认运行在8080端口,运行netstat命令查看8080端口监听的信息

[root@tomcat-1 ~]# netstat -anpt | grep java
tcp6       0      0 :::8009      :::*                    LISTEN      42330/java          
tcp6       0      0 :::8080      :::*                    LISTEN      42330/java

2.2防火墙规则配置

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[root@tomcat-1 ~]# firewall-cmd --permanent --add-port=8080/tcp
success
[root@tomcat-1 ~]# firewall-cmd --reload
success
按照相同方法在`tomcat-2`也安装

打开浏览器分别对tomcat-1tomcat-2访问测试

如果想关闭tomcat则运行/usr/local/tomcat7/bin/shutdown.sh命令 好了,大家可以看到访成功。说明我们的tomcat安装完成,下面我们来修改配置文件

[root@tomcat-1 ~]# vim /usr/local/tomcat7/conf/server.xml

设置默认虚拟主机,并增加jvmRoute

<Engine name="Catalina" defaultHost="localhost" jvmRoute="tomcat-1">

修改默认虚拟主机,并将网站文件路径指向/web/webapp1,在host段增加context

<Host name="localhost"  appBase="webapps"
     unpackWARs="true" autoDeploy="true">
<Context docBase="/web/webapp1" path="" reloadable="true"/>
</Host>

增加文档目录与测试文件

[root@tomcat-1 ~]# mkdir -p /web/webapp1
[root@tomcat-1 ~]# cd /web/webapp1/
[root@ tomcat-1 webapp1]# vi index.jsp

index.jsp内容如下

<%@page language="java" import="java.util.*" pageEncoding="UTF-8"%> 
<html> 
  <head>
<title>tomcat-1</title>
  </head>
<body>
 <h1><font color="red">Session serviced by tomcat</font></h1> 
<table aligh="center" border="1"> 
<tr> 
 <td>Session ID</td> 
         <td><%=session.getId() %></td> 
<% session.setAttribute("abc","abc");%> 
      </tr> 
<tr> 
<td>Created on</td> 
<td><%= session.getCreationTime() %></td>
</tr> 
   </table> 
</body>
<html>

停止tomcat运行,检查配置文件并启动tomcat

[root@tomcat-1 ~]# shutdown.sh
[root@tomcat-1 ~]# netstat -anpt | grep java
[root@tomcat-1 ~]# catalina.sh configtest
Using CATALINA_BASE:   /usr/local/tomcat7
Using CATALINA_HOME:   /usr/local/tomcat7
Using CATALINA_TMPDIR: /usr/local/tomcat7/temp
Using JRE_HOME:        /usr/local/java
Using CLASSPATH:       /usr/local/tomcat7/bin/bootstrap.jar:/usr/local/tomcat7/bin/tomcat-juli.jar
Nov 16, 2016 1:04:05 AM org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: /usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
Nov 16, 2016 1:04:05 AM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-bio-8080"]
Nov 16, 2016 1:04:05 AM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["ajp-bio-8009"]
Nov 16, 2016 1:04:05 AM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 534 ms
[root@tomcat-1 ~]# startup.sh 
Using CATALINA_BASE:   /usr/local/tomcat7
Using CATALINA_HOME:   /usr/local/tomcat7
Using CATALINA_TMPDIR: /usr/local/tomcat7/temp
Using JRE_HOME:        /usr/local/java
Using CLASSPATH:       /usr/local/tomcat7/bin/bootstrap.jar:/usr/local/tomcat7/bin/tomcat-juli.jar
Tomcat started.
[root@tomcat-1 ~]# netstat -anpt | grep java
tcp6       0      0 :::8009    :::*                    LISTEN      8180/java           
tcp6       0      0 :::8080    :::*                    LISTEN      8180/java

Tomcat-2节点与tomcat-1节点配置基本类似,只是jvmRoute不同,另外为了区分由哪个节点提供访问,测试页标题也不同(生产环境两个tomcat服务器提供的网页内容是相同的)。其他的配置都相同。

用浏览器访问nginx主机,验证负载均衡

第一次访问的结果

第二次访问的结果

验证健康检查的方法可以关掉一台tomcat主机,用客户端浏览器测试访问。 从上面的结果能看出两次访问,nginx把访问请求分别分发给了后端的tomcat-1tomcat-2,客户端的访问请求实现了负载均衡,但sessionid并一样。所以,到这里我们准备工作就全部完成了,下面我们来配置tomcat通过redis实现会话保持。

v.安装redis

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下载redis源码,并进行相关操作,如下:

wget http://download.redis.io/releases/redis-3.2.3.tar.gz

1.解压安装redis

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[root@redis ~]# tar zxf redis-3.2.3.tar.gz

解压完毕后,现在开始安装,如下:

[root@redis ~]# cd redis-3.2.3/
[root@redis redis-3.2.3]# make && make install

通过上图,我们可以很容易的看出,redis安装到/usr/local,/usr/local/bin,/usr/local/share,/usr/local/include,/usr/local/lib,/usr/local/share/man目录下。

2.初始化redis

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然后再切换到utils目录下,执行redis初始化脚本install_server.sh,如下:

[root@redis redis-3.2.3]# cd utils/
[root@redis utils]# ./install_server.sh
Welcome to the redis service installer
This script will help you easily set up a running redis server

Please select the redis port for this instance: [6379] 
Selecting default: 6379
Please select the redis config file name [/etc/redis/6379.conf] 
Selected default - /etc/redis/6379.conf
Please select the redis log file name [/var/log/redis_6379.log] 
Selected default - /var/log/redis_6379.log
Please select the data directory for this instance [/var/lib/redis/6379] 
Selected default - /var/lib/redis/6379
Please select the redis executable path [/usr/local/bin/redis-server] 
Selected config:
Port           : 6379
Config file    : /etc/redis/6379.conf
Log file       : /var/log/redis_6379.log
Data dir       : /var/lib/redis/6379
Executable     : /usr/local/bin/redis-server
Cli Executable : /usr/local/bin/redis-cli
Is this ok? Then press ENTER to go on or Ctrl-C to abort.
Copied /tmp/6379.conf => /etc/init.d/redis_6379
Installing service...
Successfully added to chkconfig!
Successfully added to runlevels 345!
Starting Redis server...
Installation successful!

通过上面的安装过程,我们可以看出redis初始化后redis配置文件为/etc/redis/6379.conf,日志文件为/var/log/redis_6379.log,数据文件dump.rdb存放到/var/lib/redis/6379目录下,启动脚本为/etc/init.d/redis_6379

3.systemd

回目录

现在我们要使用 systemd,所以在/etc/systems/system下创建一个单位文件名字为 redis_6379.service

[root@redis utils]# vi /etc/systemd/system/redis_6379.service

内容如下

[Unit]
Description=Redis on port 6379
[Service]
Type=forking
ExecStart=/etc/init.d/redis_6379 start
ExecStop=/etc/init.d/redis_6379 stop
[Install]
WantedBy=multi-user.target

注:这里Type=forking是后台运行的形式

4.启动redis

回目录

[root@redis utils]# systemctl daemon-reload 
[root@redis utils]# systemctl enable redis_6379.service
[root@redis utils]# systemctl start redis_6379.service
[root@redis utils]# systemctl status redis_6379.service 
● redis_6379.service - Redis on port 6379
   Loaded: loaded (/etc/systemd/system/redis_6379.service; enabled; vendor preset: disabled)
   Active: active (running) since Wed 2016-11-16 21:07:26 CST; 4min 25s ago
  Process: 7732 ExecStart=/etc/init.d/redis_6379 start (code=exited, status=0/SUCCESS)
 Main PID: 7734 (redis-server)
   CGroup: /system.slice/redis_6379.service
           └─7734 /usr/local/bin/redis-server 127.0.0.1:6379

Nov 16 21:07:26 redis systemd[1]: Starting Redis on port 6379...
Nov 16 21:07:26 redis redis_6379[7732]: Starting Redis server...
Nov 16 21:07:26 redis systemd[1]: Started Redis on port 6379.
[root@redis utils]# netstat -anpt | grep 6379
tcp        0      0 127.0.0.1:6379     0.0.0.0:*     LISTEN      7734/redis-server 1

从显示结果可以看到redis默认监听的是127.0.0.16379端口

5.防火墙规则设置

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[root@redis utils]# firewall-cmd --permanent --add-port=6379/tcp
success
[root@redis utils]# firewall-cmd --reload 
success

6.redis version

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现在来查看redis版本使用redis-cli –version命令,如下

[root@redis utils]# redis-cli --version
redis-cli 3.2.3

通过显示结果,我们可以看到redis版本是3.2.3。到此源码方式安装redis就介绍完毕。

redis安装完毕之后,我们再来配置redis设置redis监听的地址,添加监听redis主机的ip考虑到安全性,我们需要启用redis的密码验证功能requirepass参数

7.最终redis配置文件如下

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[root@redis ~]# grep -Ev '^#|^$' /etc/redis/6379.conf 
bind 127.0.0.1 192.168.31.106 
protected-mode yes
port 6379
tcp-backlog 511
timeout 0
tcp-keepalive 300
daemonize yes
supervised no
pidfile /var/run/redis_6379.pid
loglevel notice
logfile /var/log/redis_6379.log
databases 16
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
dbfilename dump.rdb
dir /var/lib/redis/6379
slave-serve-stale-data yes
slave-read-only yes
repl-diskless-sync no
repl-diskless-sync-delay 5
repl-disable-tcp-nodelay no
slave-priority 100
requirepass pwd@123
appendonly no
appendfilename "appendonly.aof"
appendfsync everysec
no-appendfsync-on-rewrite no
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
aof-load-truncated yes
lua-time-limit 5000
slowlog-log-slower-than 10000
slowlog-max-len 128
latency-monitor-threshold 0
notify-keyspace-events ""
hash-max-ziplist-entries 512
hash-max-ziplist-value 64
list-max-ziplist-size -2
list-compress-depth 0
set-max-intset-entries 512
zset-max-ziplist-entries 128
zset-max-ziplist-value 64
hll-sparse-max-bytes 3000
activerehashing yes
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit slave 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
hz 10
aof-rewrite-incremental-fsync yes

8.重新启动redis服务

回目录

[root@redis ~]# systemctl restart redis_6379.service
[root@redis ~]# netstat -anpt | grep redis
tcp   0   0 192.168.31.106:6379     0.0.0.0:*   LISTEN      8418/redis-server 1

redis配置文件配置完毕后,我们来启动redis并进行简单的操作。如下:

[root@redis ~]# redis-cli -h 192.168.31.106 -p 6379 -a pwd@123
192.168.31.106:6379> keys *
(empty list or set)
192.168.31.106:6379> set name lisi
OK
192.168.31.106:6379> get name
"lisi"
192.168.31.106:6379>

说明:

关于redis-cli -h 192.168.31.106 -p 6379 -a pwd@123的参数解释

这条命令是说要连接redis服务器,

  • IP192.168.31.106
  • 端口是6379
  • 密码是pwd@123
  • keys *是查看redis所有的键值对
  • set name lisi添加一个键值name,内容为lisi
  • get name查看name这个键值的内容

redis的命令使用暂时我们就介绍这么多

vi.配置tomcat session redis同步

回目录

1.下载tomcat-redis-session-manager相应的jar包,主要有三个:

回目录

  • tomcat-redis-session-manage-tomcat7.jar
  • jedis-2.5.2.jar
  • commons-pool2-2.2.jar

下载完成后拷贝到$TOMCAT_HOME/lib

[root@tomcat-1 ~]# cp tomcat-redis-session-manage-tomcat7.jar jedis-2.5.2.jar commons-pool2-2.2.jar /usr/local/tomcat7/lib/

2.修改tomcatcontext.xml

回目录

[root@tomcat-1 ~]# cat /usr/local/tomcat7/conf/context.xml 
<?xml version='1.0' encoding='utf-8'?>
<!--
  Licensed to the Apache Software Foundation (ASF) under one or more
  contributor license agreements.  See the NOTICE file distributed with
  this work for additional information regarding copyright ownership.
  The ASF licenses this file to You under the Apache License, Version 2.0
  (the "License"); you may not use this file except in compliance with
  the License.  You may obtain a copy of the License at
      http://www.apache.org/licenses/LICENSE-2.0
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
-->
<!-- The contents of this file will be loaded for each web application -->
<Context>
    <!-- Default set of monitored resources -->
    <WatchedResource>WEB-INF/web.xml</WatchedResource>
    <!-- Uncomment this to disable session persistence across Tomcat restarts -->
    <!--
    <Manager pathname="" />
    -->
    <!-- Uncomment this to enable Comet connection tacking (provides events
         on session expiration as well as webapp lifecycle) -->
    <!--
    <Valve className="org.apache.catalina.valves.CometConnectionManagerValve" />
    -->
    <Valve className="com.orangefunction.tomcat.redissessions.RedisSessionHandlerValve" />
    <Manager className="com.orangefunction.tomcat.redissessions.RedisSessionManager"
host="192.168.31.106"
password="pwd@123"
    port="6379"
    database="0"
    maxInactiveInterval="60" />
</Context>

3.重启tomcat服务

回目录

说明:

maxInactiveInterval="60"session的失效时间

[root@tomcat-1 ~]# shutdown.sh 
Using CATALINA_BASE:   /usr/local/tomcat7
Using CATALINA_HOME:   /usr/local/tomcat7
Using CATALINA_TMPDIR: /usr/local/tomcat7/temp
Using JRE_HOME:        /usr/local/java
Using CLASSPATH:       /usr/local/tomcat7/bin/bootstrap.jar:/usr/local/tomcat7/bin/tomcat-juli.jar
[root@tomcat-1 ~]# startup.sh 
Using CATALINA_BASE:   /usr/local/tomcat7
Using CATALINA_HOME:   /usr/local/tomcat7
Using CATALINA_TMPDIR: /usr/local/tomcat7/temp
Using JRE_HOME:        /usr/local/java
Using CLASSPATH:       /usr/local/tomcat7/bin/bootstrap.jar:/usr/local/tomcat7/bin/tomcat-juli.jar
Tomcat started.
`tomcat-2`执行和`tomcat-1`相同的操作

通过浏览器访问http://192.168.31.141/index.jsp测试页

刷新页面

可以看出,分别访问了不同的tomcat,但是得到的session却是相同的,说明达到了集群的目的。

注:从Tomcat6开始默认开启了Session持久化设置,测试时可以关闭本地Session持久化,其实也很简单,在Tomcatconf目录下的context.xml文件中,取消注释下面那段配置即可:

修改前:

<!-- Uncomment this to disable session persistence across Tomcat restarts -->
<!--
<Manager pathname="" />
-->

修改后:

<!-- Uncomment this to disable session persistence across Tomcat restarts -->
<Manager pathname="" />

重启tomcat服务

查看redis

[root@redis ~]# redis-cli -h 192.168.31.106 -p 6379 -a pwd@123
192.168.31.106:6379> keys *
1) "6C3F950BE6413AD2E0EF00F930881224.tomcat-1.tomcat-1"
2) "name"
3) "7A6D5D4C5B1EA52C4E9EED1C5523FEB5.tomcat-2.tomcat-2"
4) "32C35EEA064884F065E93CB00C690662.tomcat-1.tomcat-1"

vii.tomcat连接数据库

回目录

1.192.168.31.225作为mysql数据库服务器

回目录

[root@db ~]# mysql -uroot -p123.abc
mysql> grant all on *.* to javauser@'192.168.31.%' identified by 'javapasswd';
Query OK, 0 rows affected, 1 warning (0.02 sec)

mysql> create database javatest;
Query OK, 1 row affected (0.01 sec)

mysql> use javatest;
Database changed

mysql> create table testdata(id int not null auto_increment primary key,foo varchar(25),bar int);
Query OK, 0 rows affected (0.02 sec)

2.插入些数据

回目录

mysql> insert into testdata(foo,bar) values ('hello','123456'),('ok','654321');
Query OK, 2 rows affected (0.04 sec)
Records: 2  Duplicates: 0  Warnings: 0
mysql> select * from testdata;
+----+-------+--------+
| id | foo   | bar    |
+----+-------+--------+
|  1 | hello | 123456 |
|  2 | ok    | 654321 |
+----+-------+--------+
2 rows in set (0.00 sec)

3.mysql防火墙配置

回目录

配置tomcat服务器连接mysql数据库

4.tomcat连接mysql

回目录

下载mysql-connector-java-5.1.22-bin.jar并复制到$CATALINA_HOME/lib目录下

[root@tomcat-1 ~]# cp mysql-connector-java-5.1.22-bin.jar /usr/local/tomcat7/lib/
[root@tomcat-1 ~]# ls /usr/local/tomcat7/lib/mysql-connector-java-5.1.22-bin.jar 
/usr/local/tomcat7/lib/mysql-connector-java-5.1.22-bin.jar

context configuration
configure the JNDI datasource in tomcat by adding a declaration for your resource to your context
[root@tomcat-1 ~]# vi /usr/local/tomcat7/conf/context.xml

5.在<Context>中添加如下内容

回目录

    <Resource name="jdbc/TestDB" auth="Container" type="javax.sql.DataSource"
               maxActive="100" maxIdle="30" maxWait="10000"
               username="javauser" password="javapass" driverClassName="com.mysql.jdbc.Driver"
               url="jdbc:mysql://192.168.31.225:3306/javatest"/>

保存修改并退出

web.xml configuration

[root@tomcat-1 ~]# mkdir /web/webapp1/WEB-INF
[root@tomcat-1 ~]# vi /web/webapp1/WEB-INF/web.xml

添加内容如下

<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
    version="2.4">
  <description>MySQL Test App</description>
  <resource-ref>
      <description>DB Connection</description>
      <res-ref-name>jdbc/TestDB</res-ref-name>
      <res-type>javax.sql.DataSource</res-type>
      <res-auth>Container</res-auth>
  </resource-ref>
</web-app>

保存修改并退出,重启tomcat服务

[root@tomcat-1 ~]# shutdown.sh 
Using CATALINA_BASE:   /usr/local/tomcat7
Using CATALINA_HOME:   /usr/local/tomcat7
Using CATALINA_TMPDIR: /usr/local/tomcat7/temp
Using JRE_HOME:        /usr/local/java
Using CLASSPATH:       /usr/local/tomcat7/bin/bootstrap.jar:/usr/local/tomcat7/bin/tomcat-juli.jar
[root@tomcat-1 ~]# startup.sh 
Using CATALINA_BASE:   /usr/local/tomcat7
Using CATALINA_HOME:   /usr/local/tomcat7
Using CATALINA_TMPDIR: /usr/local/tomcat7/temp
Using JRE_HOME:        /usr/local/java
Using CLASSPATH:       /usr/local/tomcat7/bin/bootstrap.jar:/usr/local/tomcat7/bin/tomcat-juli.jar
Tomcat started.
`tomcat-2`进行和`tomcat-1`相同的操用

Test code

Now create a simple test.jsp page,内容如下:

6.test.jsp

回目录

[root@tomcat-2 ~]# vi /web/webapp1/test.jsp
[root@tomcat-2 webapp1]# cat test.jsp 
<%@ page language="java" import="java.sql.*" pageEncoding="GB2312"%>
<html>
  <head>
    <title>MySQL</title>
  </head>
<body>
connect MySQL<br>
<%
String driverClass="com.mysql.jdbc.Driver";
String url="jdbc:mysql://192.168.31.225:3306/javatest";
String username = "javauser"; 
String password = "javapasswd"; 
Class.forName(driverClass); 
Connection conn=DriverManager.getConnection(url, username, password); 
Statement stmt=conn.createStatement();
ResultSet rs = stmt.executeQuery("select * from testdata"); 
while(rs.next()){
 out.println("<br>foo:"+rs.getString(2)+"bar:"+rs.getString(3));
}
rs.close();
stmt.close();
conn.close();
%>
</body></html>

通过浏览器访问http://192.168.31.141/test.jsp测试页

注:

以上配置可以参考tomcat docs

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