Nginx+keepalived负载均衡高可用

结构图

环境：
主 服务器：192.168.239.10 
备 服务器：192.168.239.20
Web 服务器1：192.168.239.40
Web 服务器2：192.168.239.30
vip：192.168.239.100 
客户端：192.168.239.200

配置两台节点web服务器（192.168.239.30、192.168.239.40 ）

配置第一台节点服务器（192.168.239.30）

这里我用的tomcat作为web服务器当然也可以用nginx与apache作为web服务器

#首先将tomcat所需软件包拉入opt目录并关闭防火墙
systemctl stop firewalld
systemctl disable firewalld
setenforce 0
#安装jdk
cd /opt
rpm -ivh jdk-8u201-linux-x64.rpm
#设置jdk的环境变量
vim /etc/profile.d/java.sh
export JAVA_HOME=/usr/java/jdk1.8.0_201-amd64
export JRE_HOME=$JAVA_HOME/jre
export CLASSPATH=.:$JAVA_HOME/lib:$JRE_HOME/lib
export PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATH
source /etc/profile.d/java.sh
java -version
#安装tomcat
tar zxvf apache-tomcat-8.5.16.tar.gz
mkdir /usr/local/tomcat   #创建目录作为tomcat配置配置路径
mv apache-tomcat-8.5.16 /usr/local/tomcat/
#配置tomcat环境变量
vim /etc/profile.d/tomcat.sh
export CATALINA_HOME1=/usr/local/tomcat/tomcat
export CATALINA_BASE1=/usr/local/tomcat/tomcat
export TOMCAT_HOME1=/usr/local/tomcat/tomcat
source /etc/profile.d/tomcat.sh
#修改 tomcat1 实例中的 startup.sh 和 shutdown.sh 文件，添加 tomcat 环境变量
vim /usr/local/tomcat/apache-tomcat-8.5.16/bin/startup.sh
-----------------------------------------------------------------------------
export CATALINA_BASE=$CATALINA_BASE
export CATALINA_HOME=$CATALINA_HOME
export TOMCAT_HOME=$TOMCAT_HOME

vim /usr/local/tomcat/apache-tomcat-8.5.16/bin/shutdown.sh
-----------------------------------------------------------------------------
export CATALINA_BASE=$CATALINA_BASE
export CATALINA_HOME=$CATALINA_HOME
export TOMCAT_HOME=$TOMCAT_HOME
#开启服务到此tomcat就安装好了
/usr/local/tomcat/apache-tomcat-8.5.16/bin/startup.sh
#添加站点目录文件
mkdir /usr/local/tomcat/apache-tomcat-8.5.16/webapps/test
vim /usr/local/tomcat/apache-tomcat-8.5.16/webapps/test/index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<html>
<head>
<title>JSP test1 page</title>
</head>
<body>
<% out.println("this is dynamic web1");%>
</body>
</html>
#由于主机名 name 配置都为 localhost，需要删除前面的 HOST 配置
vim /usr/local/tomcat/apache-tomcat-8.5.16/conf/server.xml
<Host name="localhost" appBase="webapps" unpackWARs="true" autoDeploy="true" xmlValidation="false" xmlNamespaceAware="false">
        <Context docBase="/usr/local/tomcat/apache-tomcat-8.5.16/webapps/test/" path="" reloadable="true" />
#开启服务
/usr/local/tomcat/apache-tomcat-8.5.16/bin/shutdown.sh
/usr/local/tomcat/apache-tomcat-8.5.16/bin/startup.sh

配置第二台节点服务器（192.168.239.40）

配置与第一台tomcat一致唯一不同站点目录网页文档用于区分实现负载均衡

vim /usr/local/tomcat/apache-tomcat-8.5.16/webapps/test/index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<html>
<head>
<title>JSP test2 page</title>
</head>
<body>
<% out.println("this is dynamic web2");%>
</body>
</html>

访问测试

配置负载调度器（主：192.168.239.10）

#关闭防火墙
systemctl stop firewalld.service
setenforce 0
#安装相关依赖包
yum -y install pcre-devel zlib-devel gcc gcc-c++ make
#创建运行用户
useradd -M -s /sbin/nologin nginx
#安装nginx
cd /opt
tar zxvf nginx-1.12.0.tar.gz -C /opt/
cd nginx-1.12.0/
./configure --prefix=/usr/local/nginx --user=nginx --grou=nginx --with-http_stub_status_module --with-stream && make && make install
#优化路径
ln -s /usr/local/nginx/sbin/nginx /usr/local/sbin/
#将nginx加入服务并给执行权限
vim /lib/systemd/system/nginx.service
[Unit]
Description=nginx
After=network.target
[Service]
Type=forking
PIDFile=/usr/local/nginx/logs/nginx.pid
ExecStart=/usr/local/nginx/sbin/nginx
ExecReload=/bin/kill -s HUP $MAINPID
ExecStop=/bin/kill -s QUIT $MAINPID
PrivateTmp=true
[Install]
WantedBy=multi-user.target
chmod 754 /lib/systemd/system/nginx.service  
#开启服务
systemctl start nginx.service
systemctl enable nginx.service
#配置四层代理
vim /usr/local/nginx/conf/nginx.conf
stream {
   log_format  main  '$remote_addr $upstream_addr - [$time_local] $status $upstream_bytes_sent';
   access_log logs/stream_access.log main;

   upstream backend_server {    #添加节点服务器地址
        server 192.168.239.30:8080;
        server 192.168.239.40:8080;
   }
server {
   listen 8080;      #监听端口
   proxy_pass backend_server;
}
}

systemctl restart nginx
#安装keepalived
yum install -y keepalived
cd /etc/keepalived
#修改配置文件
vim keepalived.conf
#定义全局参数
global_defs {
   notification_email {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   smtp_server 172.0.0.1    #修改，邮件服务指向本地
   smtp_connect_timeout 30
   router_id NGINX_01     #指定服务器（路由器）的名称，主备服务器名称须不同，主为LVS_01，备为LVS_02
}
vrrp_instance VI_1 {    #定义VRRP热备实例参数
    state MASTER        #指定热备状态，主为MASTER，备为BACKU
    interface ens33       #修改，指定承载vip地址的物理接口
    virtual_router_id 51    #修改，指定虚拟路由器的ID号，每个热备组保持一致
    priority 100       #指定优先级数值越大优先级越高
    advert_int 1       #通告间隔秒数(心跳频率)
    authentication {       #定义认证信息,每个热备组保持一致
        auth_type PASS   #认证类型
        auth_pass 1111      #修改，指定验证密码，主备服务器保持一致
    }
    virtual_ipaddress {     #指定群集vip地址
        192.168.239.100
    }
}
#编写服务控制简本当nginx服务挂掉是自动关闭keepalved服务并给脚本权限
vim check_nginx.sh
#!/bin/bash
count=$(ps -ef | grep nginx | egrep -cv "grep"|$$)
if [ $count -eq 0 ];then
systemctl stop keepalived
fi
chmod +x check_nginx.sh
#修改配置文件
vim keepalived.conf
#检测脚本
vrrp_script check_nginx {    
    script "/etc/keepalived/check_nginx.sh"  #心跳执行的脚本，检测nginx是否启动

track_script {   #调用检测脚本
    check_nginx
}
systemctl start keepalived.service
ip addr

配置负载调度器（备：192.168.239.10）

#关闭防火墙
systemctl stop firewalld.service
setenforce 0
#yum安装nginx
vim /etc/yum.repos.d/nginx.repo
[nginx-stable]
name=nginx stable repo
baseurl=http://nginx.org/packages/centos/7/$basearch/
gpgcheck=0
enabled=1
yum install nginx -y
#配置四层代理
cd /etc/nginx/
vim nginx.conf
stream {
   log_format  main  '$remote_addr $upstream_addr - [$time_local] $status #upstream_bytes_sent';
   access_log logs/stream_access.log main;

   upstream backend_server {
        server 192.168.239.30:8080;  #添加节点服务器
        server 192.168.239.40:8080;
   }
server { 
   listen 8080;  #监听地址
   proxy_pass backend_server;
}
}
#创建日志文件目录
mkdir logs
#开启服务
systemctl restart nginx
#安装keepalived服务
yum install -y keepalived
#修改配置文件与主差不多只要在其基础修改几处即可
cd /etc/keepalived
vim keepalived.conf
global_defs {
   notification_email {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   smtp_server 172.0.0.1
   smtp_connect_timeout 30
   router_id NGINX_02    #修改此处指定服务器（路由器）的名称，主备服务器名称须不同，
}
vrrp_instance VI_1 {
    state BACKUP     #指定热备状态，主为MASTER，备为BACKU
    interface ens33
    virtual_router_id 51
    priority 90      #修改此行指定优先级数值越大优先级越高
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.239.100
    }
}
#编写服务控制简本当nginx服务挂掉是自动关闭keepalved服务并给脚本权限
vim check_nginx.sh
#!/bin/bash
count=$(ps -ef | grep nginx | egrep -cv "grep"|$$)
if [ $count -eq 0 ];then
systemctl stop keepalived
fi
chmod +x check_nginx.sh

vim keepalived.conf
vrrp_script check_nginx {
    script "/etc/keepalived/check_nginx.sh"   #心跳执行的脚本，检测nginx是否启动
track_script {
    check_nginx     #调用检测脚本
}
systemctl start keepalived.service