nginx+keepalived+tomcat实现主从高可用负载均衡

设备：

1、准备四台虚拟机，两台tomcat，两台nginx

2、两台tomcat配置相同，测试页不同

两台Tomcat配置完全相同、只有测试页面不同

安装jdk和tomcat

[root@localhost ~]# rz

导入jdk以及tomcat源码包

[root@localhost ~]# tar xf apache-tomcat-8.5.16.tar.gz

[root@localhost ~]#  tar xf  jdk-8u191-linux-x64.tar.gz

[root@localhost ~]# mv jdk1.8.0_191 /usr/local/java                          #移动jdk包到/usr/local/下并取名java

[root@localhost ~]# mv apache-tomcat-8.5.16 /usr/local/tomcat        #移动tomcat包到/usr/local/下并取名tomcat

[root@localhost ~]# vi /etc/profile

在最后添加

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

[root@localhost ~]# source /etc/profile                                           #生效文件

[root@localhost ~]# /usr/local/tomcat/bin/startup.sh                       #开启服务

Tomcat1测试页：

[root@localhost ~]# echo “111111” > /usr/local/tomcat/webapps/ROOT/index.jsp

Tomcat2测试页：

[root@localhost ~]# echo “222222” > /usr/local/tomcat/webapps/ROOT/index.jsp

[root@localhost ~]# /usr/local/tomcat/bin/startup.sh                    #启动服务

[root@localhost ~]# netstat   -anpt  |  grep  :8080                        #查看8080端口
tcp6 0 0 :::8080 :::* LISTEN     9968/java

关闭防火墙

[root@localhost ~]# systemctl stop firewalld
[root@localhost ~]# iptables -F
[root@localhost ~]# setenforce 0

[root@localhost ~]# netstat -anpt | grep :8080

两台nginx配置完全相同

安装keepalived

[root@localhost ~]# yum install keepalived -y

[root@localhost ~]# cd /etc/keepalived/
[root@localhost keepalived]# ls
keepalived.conf

[root@localhost keepalived]# cp keepalived.conf keepalived.conf.bak         #备份keeplived配置文件

[root@localhost~]# vim /etc/keepalived/keepalived.conf                           #修改主配置文件

! Configuration File for keepalived
global_defs {
   notification_email {
     acassen@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   smtp_server 192.168.200.1
   smtp_connect_timeout
   router_id LVS_DEVEL
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval
   vrrp_gna_interval
}
vrrp_script chk_http_port {      #检测nginx服务是否在运行。有很多方式，比如进程，用脚本检测等等
    script "/root/nginx.sh"      #这里通过脚本监测
    interval                    #每两秒检测一次
    weight -                    #脚本结果导致的优先级变更，检测失败（脚本返回非0）则优先级 -
    fall                        #检测连续2次失败才算确定是真失败。会用weight减少优先级（-255之间）
    rise                        #检测1次成功就算成功。但不修改优先级
}
vrrp_instance VI_1 {
    state BACKUP                 #主keepalived为master，备keeplived为backup
    interface ens33
    virtual_router_id
    priority
    advert_int
    authentication {
        auth_type PASS
        auth_pass
    }
    virtual_ipaddress {
        192.168.200.254
    }
track_script {                  #执行监控的服务。
   chk_http_port                #引用VRRP脚本，即在 vrrp_script 部分指定的名字。
}
}

编写nginx心跳脚本

[root@localhost ~]# vim nginx.sh

#!/bin/bash
counter=$(ps -C nginx --no-heading|wc -l)
if [ "${counter}" = "" ]; then
    /usr/local/nginx/sbin/nginx
    sleep
    counter=$(ps -C nginx --no-heading|wc -l)
    if [ "${counter}" = "" ]; then
        systemctl stop keepalived
    fi
fi

[root@localhost~]#  chmod +x /root/nginx.sh

[root@localhost~]#  systemctl restart keeplived         #重启keepalived服务

安装Nginx

[root@localhost ~]# rz

导入Nginx源码包

[root@localhost ~]# tar xf xf nginx-1.15.9.tar.gz -C /usr/src

[root@localhost ~]# cd /usr/src/nginx-1.15.9

[root@localhost~]# ./configure --prefix=/usr/local/nginx --user=nginx --group=nginx --with-file-aio --with-http_stub_status_module --with-http_gzip_static_module --with-http_flv_module --with-http_ssl_module --with-pcre

[root@localhost~]# ln -sf /usr/local/nginx/sbin/nginx /usr/local/sbin

[root@localhost ~]# ll /usr/local/sbin/nginx
lrwxrwxrwx. 1 root root 27 10月 21 10:50 /usr/local/sbin/nginx -> /usr/local/nginx/sbin/nginx

[root@localhost~]# vim /usr/local/nginx/conf/nginx.conf

user  nginx nginx;
 
worker_processes  ;
 
error_log  logs/error.log;
 
pid        logs/nginx.pid;
 
events {
 
    use epoll;
 
    worker_connections  ;
 
}
 
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;
 
    keepalive_timeout  ;
 
    gzip  on;
 
    upstream tomcat_server {
 
        server 192.168.200.112: weight=;             #此处IP为tomcat机IP
 
        server 192.168.200.113: weight=;
 
    }
 
    server {
 
        listen       192.168.200.254:;                        #监听服务机192.168.200.254的80端口
 
        server_name  localhost;
 
        charset utf-;
 
        access_log  logs/host.access.log  main;
 
        location / {
 
            root   html;
 
            index  index.html index.htm index.jsp;
 
            proxy_pass http://tomcat_server;
 
            proxy_set_header Host $http_host;       
 
        }
 
    }
 
}

[root@localhost~]# nginx -t                              #检查语法

[root@localhost~]#nginx                                  #启动服务

[root@localhost~]#killall -HUP nginx               #启动服务

[root@localhost ~]# netstat -anpt | grep :80    #检测80端口

[root@localhost ~]# ip a

inet 192.168.200.122/24 brd 192.168.200.255 scope global noprefixroute ens33
valid_lft forever preferred_lft forever
inet 192.168.200.254/32 scope global ens33            #可以看到有多了一个192.168.200.254的网卡

测试：开启多个页面依旧是111和222分配一致