tomcat msm
准备工作准备三台虚拟机, 均为CentOS-7-x86_64最小化安装, iptables与SELinux均处于关闭状态, 配置好yum源(base和epel). 做好快照, 以便每次实验后快速恢复.
HostA
OS: CentOS-7-x86_64
hostname: 80e54d87.twoyang.com
eno16777736: 172.18.71.101/16
gateway: 172.18.0.1
HostB
OS: CentOS-7-x86_64
hostname: b9cf468b.twoyang.com
eno16777736: 172.18.71.102/16
gateway: 172.18.0.1
HostC
OS: CentOS-7-x86_64
hostname: 1f5fafa6.twoyang.com
eno16777736: 172.18.71.103/16
gateway: 172.18.0.1 先不管Memcached和MSM, 按照nginx负载均衡tomcat部署好集群.
集群初始化
建立主机信任, 时间同步, 统一增加yum源. 这一步其实在哪个节点上做都可以, 我这里选择HostA.
# 写了个脚本来做这个事情
# wget https://raw.githubusercontent.com/wqiang0917/LearnInMagedu/master/shell/sshtrust.sh
# 将集群中所有节点IP地址(包括本机)都加入这个主机列表数组
# vim sshtrust.sh
HOSTS=("172.18.71.101" "172.18.71.102" "172.18.71.103")
# 分发密钥, 建立主机信任.
# bash sshtrust.sh --key
# 同步时间
# bash sshtrust.sh "ntpdate 172.18.0.1"
# bash sshtrust.sh "hwclock --systohc"
# bash sshtrust.sh date
Tue Jun7 21:54:22 CST 2016
Tue Jun7 21:54:22 CST 2016
Tue Jun7 21:54:22 CST 2016HostA
# 安装`OpenJDK`和`Tomcat`
# yum install -y java-1.7.0-openjdk java-1.7.0-openjdk-devel tomcat tomcat-lib tomcat-admin-webapps tomcat-webapps
# echo "export JAVA_HOME=/usr" > /etc/profile.d/java.sh
# exec bash
# 创建sessapp应用, 并提供session测试主页.
# mkdir -p /var/lib/tomcat/webapps/sessapp/{classes,lib,WEB-INF,META-INF}
# cat/var/lib/tomcat/webapps/sessapp/index.jsp
TomcatA
TomcatA.magedu.com
Session ID
Created on
EOF
# 启动服务, 并检查监听端口.
# systemctl start tomcat.service
# ss -tnl | grep "\(4000\|8009\|8080\)"
LISTEN 0 100 :::8009 :::*
LISTEN 0 100 :::8080 :::*
LISTEN 0 50 ::ffff:172.18.71.101:4000 :::*HostB
# 安装`OpenJDK`和`Tomcat`
# yum install -y java-1.7.0-openjdk java-1.7.0-openjdk-devel tomcat tomcat-lib tomcat-admin-webapps tomcat-webapps
# echo "export JAVA_HOME=/usr" > /etc/profile.d/java.sh
# exec bash
# mkdir -p /var/lib/tomcat/webapps/sessapp/{classes,lib,WEB-INF,META-INF}
# 创建sessapp应用, 并提供session测试主页.
# cat/var/lib/tomcat/webapps/sessapp/index.jsp
TomcatB
TomcatB.magedu.com
Session ID
Created on
EOF
# 启动服务, 并检查监听端口.
# systemctl start tomcat.service
# ss -tnl | grep "\(4000\|8009\|8080\)"
LISTEN 0 100 :::8009 :::*
LISTEN 0 100 :::8080 :::*
LISTEN 0 50 ::ffff:172.18.71.101:4000 :::*HostC
# 首先测试使用curl直接访问HostA与HostB的sessapp.
# curl http://172.18.71.101:8080/sessapp/
TomcatA
TomcatA.magedu.com
Session ID
4D5C16AFE6FDA767E506729B0781A0B7
Created on
1465284908776
# curl http://172.18.71.102:8080/sessapp/
TomcatB
TomcatB.magedu.com
Session ID
185E2BDA227CB166CA75B7FDC1A07BE4
Created on
1465284924384
# 安装nginx作为前端调度器反代.
# yum install -y nginx
# vim /etc/nginx/nginx.conf
...
upstream tcsrvs {
server 172.18.71.101:8080 weight=1;
server 172.18.71.102:8080 weight=2;
}
server {
...
location / {
proxy_pass http://tcsrvs;
}
}
...
# 测试语法
# nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
# 启动服务
# systemctl start nginx.service
# ss -tnl | grep 80
LISTEN 0 128 *:80 *:*
LISTEN 0 128 :::80 :::* 使用浏览器访问http://172.18.71.103/sessapp/, 持续刷新页面. 可以看到通过前端调度器nginx在按照权重轮调后端服务器, 并且SessionID一直在变化. 此时使用Memcached和MSM存储会话.
注意: 不要使用curl来测试, curl不是daemon进程, 执行完就退出了, 没有办法保存会话.
Memcached和MSM
在HostA和HostB两个后端tomcat主机上均要执行以下操作, 以HostA为例.
# 安装memcached
# yum install -y memcached
# systemctl start memcached.service
# ss -tnl | grep 11211
LISTEN 0 128 *:11211 *:*
LISTEN 0 128 :::11211 :::*
# 下载MSM的类库放置在tomcat的公共类库目录中
# ls msm/
javolution-5.4.3.1.jar memcached-session-manager-tc7-1.8.3.jarspymemcached-2.11.1.jar
memcached-session-manager-1.8.3.jarmsm-javolution-serializer-1.8.3.jar
# cp msm/*.jar /usr/share/java/tomcat/
# 增加配置
# vim /etc/tomcat/server.xml
...
...
# 重启服务
# systemctl restart tomcat.service测试验证
[*] 使用浏览器访问http://172.18.71.103/sessapp/, 持续刷新页面.
http://7xltax.com1.z0.glb.clouddn.com/tomcat_msm_1.gif
可以观察到调度器一直在按照权重轮调后端服务器, 但是SessionID一直没有变化. 此时使用的是标识为n2的memcached作为主session server. 说明session可以全局共享.
注意: 不要使用curl来测试, curl不是daemon进程, 执行完就退出了, 没有办法保存会话.
[*] 关闭当前作为主session server的HostB上的memcached, 再来刷新页面.
# systemctl stop memcached.servicehttp://7xltax.com1.z0.glb.clouddn.com/tomcat_msm_2.gif
可以观察到SessionID没有变化, 而session server已经切换到了是标识为n1的memcached. 说明单个session server发生故障, 会话也不会丢失.
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