一、基本思路

1.利用nginx实现负载均衡和反向代理，减轻主服务器访问压力；

2.利用springboot实现多tomcat的session共享；

IP角色

192.168.0.170nginx(主)服务器、Tomcat服务器

192.168.0.171nginx(从)服务器、Tomcat服务器

二、安装Tengine(Nginx)并添加服务

1.Tengine简介

Tengine是由淘宝网发起的Web服务器项目。它在Nginx的基础上，针对大访问量网站的需求，添加了很多高级功能和特性。Tengine的性能和稳定性已经在大型的网站如淘宝网，天猫商城等得到了很好的检验。它的最终目标是打造一个高效、稳定、安全、易用的Web平台。

2.Tengine下载

http://tengine.taobao.org/download.html下载对应的Tengine版本

3.安装nginx对应的依赖库

yum -y install gcc openssl-devel pcre-devel zlib-devel

4.解压缩Tengine到相对应的文件夹

tar -zxvf 到相对应的文件夹

5.配置nginx对应的选项

./configure

6.安装Tengine

make & make install

7.添加nginx到服务并设置自启动

vi /lib/systemd/system/nginx.service --添加文件

---------------------添加以下代码----------------------------

[Unit]Description=The nginx HTTP and reverse proxy serverAfter=syslog.target network.target remote-fs.target nss-lookup.target [Service]Type=forkingPIDFile=/usr/local/nginx/logs/nginx.pidExecStartPre=/usr/local/nginx/sbin/nginx -tExecStart=/usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.confExecReload=/bin/kill -s HUP $MAINPIDExecStop=/bin/kill -s QUIT $MAINPIDPrivateTmp=true[Install]WantedBy=multi-user.target

# 修改文件权限

cd /lib/systemd/system/

chmod 745 nginx.service

# 设置为开机启动 systemctl enable nginx.service

# 启动nginx服务 systemctl start nginx.service

# 设置开机自启动 systemctl enable nginx.service

# 停止开机自启动 systemctl disable nginx.service

# 查看服务当前状态 systemctl status nginx.service

# 重新启动服务 systemctl restart nginx.service

# 查看所有已启动的服务 systemctl list-units --type=service

8.启动Nginx服务，浏览输入http://192.168.0.170如出现nginx相应画面标识安装成功，nginx默认端口80

三、安装Keepalived并添加服务

1.keepalived下载

下载方式一：

https://www.keepalived.org/download.html下载最新稳定版的keepalived，ftp上传到home目录下

yum install -y gcc gcc-c++ openssl-devel 安装依赖库，如已经安装可不比进行此操作

下载方式二：

wget https://www.keepalived.org/software/keepalived-2.0.19.tar.gz

2.解压缩keepalived文件

进入到home目录先

cd /home

tar -zxvf keepalived-2.0.19.tar.gz

3.检查配置

cd keepalived-2.0.19

./configure --prefix=/usr/local/keepalived

若系统出现如下警告

“*** WARNING - this build will not support IPVS with IPv6. Please install libnl/libnl-3 dev libraries to support IPv6 with IPVS.”

yum -y install libnl libnl-devel　执行此命令，重新进行./configure --prefix=/usr/local/keepalived 操作

4.安装

make & make install

5.配置keepalived服务

mkdir -p /etc/keepalived

cp /usr/local/keepalived/sbin/keepalived /usr/sbin/

cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf

cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/

cp keepalived/etc/init.d/keepalived /etc/init.d/

chmod 755 /etc/init.d/keepalived

vi /lib/systemd/system/keepalived.service 编辑keepalived服务文件

将所有的字符串 “/usr/local/keepalived” 替换为空白，替换完如下：

----------------------------------------------------------------------------------------------------------------------------

[Unit]Description=LVS and VRRP High Availability MonitorAfter=network-online.target syslog.targetWants=network-online.target[Service]Type=forkingPIDFile=/run/keepalived.pid#KillMode=processEnvironmentFile=-/etc/sysconfig/keepalivedExecStart=/sbin/keepalived $KEEPALIVED_OPTIONSExecReload=/bin/kill -HUP $MAINPID[Install]WantedBy=multi-user.target

systemctl daemon-reload 重读配置

6.修改keepalived.conf

vi /etc/keepalived/keepalived.conf

------------------------------------------------按照以下代码修改(master服务器192.168.0.170)------------------

! Configuration File for keepalivedglobal_defs {## keepalived 自带的邮件提醒需要开启 sendmail 服务。 建议用独立的监控或第三方 SMTProuter_id tdrc ## 标识本节点的字条串，通常为 hostname} ## keepalived 会定时执行脚本并对脚本执行的结果进行分析，动态调整 vrrp_instance 的优先级。如果脚本执行结果为 0，并且 weight 配置的值大于 0，则优先级相应的增加。如果脚本执行结果非 0，并且 weight配置的值小于 0，则优先级相应的减少。其他情况，维持原本配置的优先级，即配置文件中 priority 对应的值。vrrp_script chk_nginx {script "/etc/keepalived/nginx_check.sh" ## 检测 nginx 状态的脚本路径interval 2 ## 检测时间间隔weight -20 ## 如果条件成立，权重-20}## 定义虚拟路由， VI_1 为虚拟路由的标示符，自己定义名称vrrp_instance VI_1 {state MASTER ## 主节点为 MASTER， 对应的备份节点为 BACKUPinterface ens33 ## 绑定虚拟 IP 的网络接口，与本机 IP 地址所在的网络接口相同， 我的是 eth0virtual_router_id 33 ## 虚拟路由的 ID 号， 两个节点设置必须一样， 可选 IP 最后一段使用, 相同的 VRID 为一个组，他将决定多播的 MAC 地址mcast_src_ip 192.168.0.170 ## 本机 IP 地址priority 100 ## 节点优先级， 值范围 0-254， MASTER 要比 BACKUP 高nopreempt ## 优先级高的设置 nopreempt 解决异常恢复后再次抢占的问题advert_int 1 ## 组播信息发送间隔，两个节点设置必须一样， 默认 1s## 设置验证信息，两个节点必须一致authentication {auth_type PASSauth_pass 1111 ## 真实生产，按需求对应该过来}## 将 track_script 块加入 instance 配置块track_script {chk_nginx ## 执行 Nginx 监控的服务} ## 虚拟 IP 池, 两个节点设置必须一样virtual_ipaddress {192.168.0.180 ## 虚拟 ip，可以定义多个}}

----------------------------------------按照以下代码修改(slave服务器192.168.0.171)-----------------------------

! Configuration File for keepalivedglobal_defs {router_id tdrc}vrrp_script chk_nginx {script "/etc/keepalived/nginx_check.sh"interval 2weight -20}vrrp_instance VI_1 {state BACKUPinterface ens33virtual_router_id 33mcast_src_ip 192.168.0.171priority 90advert_int 1authentication {auth_type PASSauth_pass 1111}track_script {chk_nginx}virtual_ipaddress {192.168.0.180}}

--------------------------------------------------------------------------------------------------------------------------

7. /etc/keepalived 下添加nginx_check.sh脚本

-----------------------------------------------master(slave)服务器下添加以下代码---------------------------------------

#!/bin/bashcounter=$(ps -C nginx --no-heading|wc -l)echo "$counter"if [ "${counter}" = "0" ]; then    /usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf    sleep 2    counter=$(ps -C nginx --no-heading|wc -l)    if [ "${counter}" = "0" ]; then        /etc/init.d/keepalived stop    fifi

------------------------------------------------------------------------------------------------------------------

保存后，给脚本赋执行权限：

# chmod +x /etc/keepalived/nginx_check.sh

8.重启nginx和keepqlived

浏览器访问(VIP)192.068.0.180 或192.168.0.170 或192.168.0.171

四、Nginx配置多个应用

测试需提前在192.168.0.170和192.168.0.171上部署号相应的测试应用

vi /usr/local/nginx/conf/nginx.conf

htt{}中添加

upstream cluster {

# 服务器访问的路径，可以指定多个服务器，此处可根据需求配置单个或者多个应用服务器、负载均衡策略

server 192.168.0.170:8080 weight=1;

server 192.168.0.171:8080 weight=1;

}

server{}中添加

location / {

proxy_pass http://cluster;

root html;

index index.html index.htm;

}

五、实现多应用服务器session共享

测试应用采用的是springboot，springboot自带session注释，@EnableRedisHttpSession

部分内容参考自https://blog.csdn.net/qq_33200967/article/details/80707616