LB/LVS之KeepAlived

本文主要是介绍LB/LVS之KeepAlived，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

基于LVS LB集群解决方案一：LVS + KeepAlived

KeepAlived在该项目中的功能：
1. 实现调度器的HA
2. 对RealServer做健康检查
3. 动态维护IPVS路由表
http://www.keepalived.org
=================================================================================

拓扑结构：
Client： CIP： 192.168.122.1

Director：          VIP：192.168.122.100
      DIP:     director1 192.168.122.2   director2 192.168.122.3

Real Server： RIP： 192.168.122.10    192.168.122.20 192.168.122.30
       VIP： 192.168.122.100 192.168.122.100 192.168.122.100

DNS Server： www.uplook.com ===> 192.168.122.100
注：主/备Directory VIP由高可用软件添加

一、实施步骤
1. 准备工作（集群中所有主机）
IP, hostname, hosts, iptables, SELinux, ssh trust, ntp
[root@uplook ~]# cat /etc/hosts
127.0.0.1                localhost
192.168.122.2      director1.uplook.com director1
192.168.122.3      director2.uplook.com director1
192.168.122.10     node1.uplook.com node1
192.168.122.20     node2.uplook.com node2
192.168.122.30     node3.uplook.com node3

2. RS配置
配置好网站服务器，测试所有RS //为了测试效果，提供不同的页面
[root@uplook ~]# ip addr add dev lo 192.168.122.100/32 //在lo接口上绑定VIP

方法一：不对VIP的ARP请求响应
[root@uplook ~]# echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore //non-arp
[root@uplook ~]# echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce

方法二：不对VIP的ARP请求响应
[root@uplook ~]# arptables -A IN -d 192.168.122.100 -j DROP
[root@uplook ~]# arptables -A OUT -s 192.168.122.100 -j mangle --mangle-ip-s <real_ip>
[root@uplook ~]# service arptables_jf save
[root@uplook ~]# chkconfig arptables_jf on

3. 主/备调度器安装软件
[root@master ~]# yum -y install ipvsadm keepalived
[root@backup ~]# yum -y install ipvsadm keepalived

=================================================================================
源码安装方法
ipvsadm
[root@uplook ~]# yum -y install ipvsadm kernel-headers kernel-devel openssl-devel popt-devel

KeepAlived
[root@uplook keepalived-1.2.1]# ./configure --prefix=/ --with-kernel-dir=/usr/src/kernels/2.6.32-358.el6.x86_64/
Keepalived configuration
---------------------------------------------
Keepalived version   : 1.2.1
Compiler                 : gcc
Compiler flags         : -g -O2 -DETHERTYPE_IPV6=0x86dd
Extra Lib                : -lpopt -lssl -lcrypto
Use IPVS Framework : Yes
IPVS sync daemon support : Yes
Use VRRP Framework       : Yes
Use Debug flags          : No
[root@uplook keepalived-1.2.1]# make
[root@uplook keepalived-1.2.1]# make install
=================================================================================

4. 主/备调度器Keepalived配置
Master
获得Real Server测试页面的MD5SUM值　<用于对Real Server健康检查>
[root@uplook ~]# genhash -s 192.168.122.10 -p 80 -u /test.html //RS网站的主目录
MD5SUM = c5f42eddf777ef2d2b0f7263c094c20e

[root@uplook ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
router_id director1 //辅助改为director2
}

vrrp_instance VI_1 {
    state MASTER    //辅助改为BACKUP
    interface eth0    //心跳接口，尽量单独连接心跳
   virtual_router_id 80  //MASTER,BACKUP一致
    priority 100     //辅助改为50
    advert_int 1              设置同步时间间隔
    authentication {      设置验证类型和密码
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {       设置lvs vip
        192.168.122.100
    }
}

virtual_server 192.168.122.100 80 {
    delay_loop 6 健康检查时间间隔
    lb_algo rr     负载均衡调度算法
    lb_kind DR   负载均衡转发规则
    nat_mask 255.255.255.0
    persistence_timeout 50 设置会话保持时间
    protocol TCP

    real_server 192.168.122.10 80 {
        weight 1
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80
        }
    }

    real_server 192.168.122.20 80 {
        weight 1
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80
        }
    }

    real_server 192.168.122.30 80 {
        weight 1
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80
        }
     }
}

BACKUP

5. 启动KeepAlived（主备均启动）
[root@uplook ~]# chkconfig keepalived on
[root@uplook ~]# service keepalived start
[root@uplook ~]# tail -f /var/log/messages

[root@uplook ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP 192.168.122.100:80 wrr
-> 192.168.122.10:80               Route   1      0          0
-> 192.168.122.20:80               Route   3      0          0
-> 192.168.122.30:80               Route   3      0          0

[root@uplook ~]# ipvsadm -Ln -c
IPVS connection entries
pro expire state       source             virtual            destination
TCP 01:57 FIN_WAIT    192.168.1.254:58698 192.168.122.100:80    192.168.122.10:80
TCP 01:57 FIN_WAIT    192.168.1.254:58699 192.168.122.100:80    192.168.122.20:80
TCP 01:57 FIN_WAIT    192.168.1.254:58695 192.168.122.100:80    192.168.122.20:80
TCP 01:56 FIN_WAIT    192.168.1.254:58691 192.168.122.100:80    192.168.122.20:80
TCP 01:58 FIN_WAIT    192.168.1.254:58700 192.168.122.100:80    192.168.122.20:80
TCP 01:58 FIN_WAIT    192.168.1.254:58702 192.168.122.100:80    192.168.122.10:80
TCP 01:58 FIN_WAIT    192.168.1.254:58703 192.168.122.100:80    192.168.122.20:80
TCP 01:57 FIN_WAIT    192.168.1.254:58696 192.168.122.100:80    192.168.122.20:80
TCP 01:57 FIN_WAIT    192.168.1.254:58693 192.168.122.100:80    192.168.122.20:80

二、测试
所有分发器和Real Server都正常

主分发器故障及恢复

Real Server故障及恢复

三、Keepalived不抢占
nopreempt 仅针对BACKUP