0656-6.2.0-如何配置Haproxy高可用

Fayson的github： https://github.com/fayson/cdhproject

推荐关注微信公众号：“Hadoop实操”，ID：gh_c4c535955d0f

1 文档编写目的

Fayson在之前的文章有提到《如何使用HAProxy实现HiveServer2负载均衡》《如何使用HAProxy实现Impala的负载均衡》集群采用了haproxy保证了集群服务的高可用，但是Haproxy本身并没有实现热备，在Haproxy服务器出现问题时，需要手动切换。本文主要介绍如何采用keepalived解决实在Haproxy高可用。

测试环境：

1.RedHat7.2

2.CDH6.2.0

2 操作步骤

2.1 安装配置Haproxy

两个节点都安装Haproxy

yum -y install haproxy

两个节点配置Haproxy

两个节点启动并加入开机自启

界面查看两个节点配置是否正确，访问是否正常

2.2 安装keepalived

两个节点都安装

yum -y install keepalived

添加到开机自启动

2.3 配置HA

1．两个节点同时配置

编辑脚本/etc/keepalived/haproxy_check.sh，脚本内容如下(haproxy_check.sh)，两个节点都需要该脚本。

#!/bin/bash
A=`ps -C haproxy --no-header | wc -l`
if [ $A -eq 0 ];then
/etc/init.d/haproxy start
sleep 3
if [ `ps -C haproxy --no-header | wc -l ` -eq 0 ];then
/etc/init.d/keepalived stop
fi
fi

增加执行权限

chmod +x /etc/keepalived/haproxy_check.sh

2．节点cdh234.macro.com配置Keepalived

修改配置文件/etc/keepalived/keepalived.conf,配置vip为192.168.0.245

启动Keepalived服务

systemctl start keepalived

vip已绑定成功

cdh235.macro.com节点ping 192.168.0.245

停止Keepalived服务后查看192.168.0.245已从网卡ens192解绑

3．节点cdh235.macro.com配置Keepalived

修改配置文件/etc/keepalived/keepalived.conf,配置vip为192.168.0.245

启动Keepalived服务

systemctl start keepalived

vip已绑定成功

cdh234.macro.com节点ping 192.168.0.245

2.4 验证Keepalived服务IP漂移

两个节点同时起Keepalived

只有其中一个节点cdh235.macro.com绑定了vip 192.168.0.245

停止cdh235.macro.com的服务Keepalived，cdh235.macro.com解绑vip，cdh234.macro.com绑定vip

2.5 验证Haproxy的高可用

vip绑定在cdh234.macro.com节点上

使用vip:1080/stats访问Haproxy的web界面成功

停止cdh234.macro.com节点的Haproxy,vip已没有绑定;vip 绑定到节点cdh235.macro.com

依然可以访问