一 基础准备
1.1 部署环境及说明
系统OS：CentOS 6.8 64位
HAProxy软件：HA-Proxy version 1.5.18
Keepalived软件：keepalived-1.3.6.tar.gz
官方链接：http://www.haproxy.org/ （国内可能无法打开）
下载连接：http://pkgs.fedoraproject.org/repo/pkgs/haproxy/
部署说明：当用户访问对应的域名时，HAProxy能将请求发送到对应的后端主机上，同时当主HAProxy服务器发生故障后，能立刻将负载均衡服务切换到备用HAProxy服务器上。
主机名 | 主机IP地址 | 集群角色 | 虚机IP/域名 |
master | 172.24.8.10 | 主HAProxy服务器 | 172.24.8.100 |
backup | 172.24.8.11 | 备HAProxy服务器 | |
webapp1 | 172.24.8.30 | 后端web服务器 | www.lz.com |
webapp2 | 172.24.8.31 | static.lz.com | |
webapp3 | 172.24.8.32 | video.lz.com |
1.2 架构规划
二 后端httpd集群部署
2.1 部署httpd集群
[root@webapp1 ~]# yum -y install httpd
[root@webapp1 ~]# vi /var/www/html/index.html
This is my www.lz.com!
[root@webapp1 ~]# vi /var/www/html/index.html
This is my static.lz.com!
[root@webapp1 ~]# vi /var/www/html/index.html
This is my video.lz.com!
[root@webapp1 ~]# systemctl start httpd.service
[root@webapp1 ~]# systemctl enable httpd.service
[root@webapp1 ~]# systemctl stop firewalld.service
[root@webapp1 ~]# systemctl disable firewalld.service
[root@webapp1 ~]# vi /etc/selinux/config
SELINUX=disabled
[root@webapp1 ~]# setenforce 0 #关闭SELinux及防火墙
注意：后端real server节点都需要安装，本环境针对httpd简单安装即可，无需过多配置。
三 基础NTP部署
3.1 NTP部署
[root@webapp1 ~]# yum -y install ntp
[root@webapp1 ~]# systemctl start ntpd.service
建议：替换附件中的ntp配置文件，建议采用阿里云时钟进行同步。
注意：为了保证集群的稳定性，强烈建议在所有节点均部署NTP同步服务，保证所有时钟一致。
四 Keepalived部署
4.1 编译环境
安装基础环境及依赖：
# yum -y install gcc gcc-c++ make kernel-devel kernel-tools kernel-tools-libs kernel libnl libnl-devel libnfnetlink-devel openssl-devel wget openssh-clients
4.2 安装Keepalived
[root@haproxy_master ~]# wget http://www.keepalived.org/software/keepalived-1.3.6.tar.gz
[root@haproxy_master ~]# tar -zxvf keepalived-1.3.6.tar.gz
[root@haproxy_master ~]# cd keepalived-1.3.6/
[root@lvsmaster keepalived-1.3.6]# ./configure --prefix=/usr/local/keepalived
[root@haproxy_master keepalived-1.3.6]# make && make install
注意：CentOS6.8安装高于1.3.6版本会出现未知错误。
4.3 添加Keepalived启动相关服务
[root@haproxy_master ~]# mkdir /etc/keepalived
[root@haproxy_master ~]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
[root@haproxy_master ~]# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
[root@haproxy_master ~]# cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
[root@haproxy_master ~]# vi /etc/init.d/keepalived #创建Keepalived启动脚本，见附件
[root@haproxy_master ~]# chmod u+x /etc/rc.d/init.d/keepalived
4.4 配置Keepalived
[root@haproxy_master ~]# vi /etc/keepalived/keepalived.conf
global_defs {
notification_email {
#……
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 192.168.200.1
smtp_connect_timeout 30
router_id LVS_DEVEL
} vrrp_script check_haproxy {
script "/usr/bin/killall -0 haproxy"
interval 2
weight 21
} vrrp_instance HAProxy_HA {
state BACKUP #在HAProxy主备均设置为BACKUP
interface eth0
virtual_router_id 80
priority 100
advert_int 2
nopreempt #不抢占模式
authentication {
auth_type PASS
auth_pass 1111
} notify_master "/etc/keepalived/master.sh"
notify_backup "/etc/keepalived/backup.sh"
notify_fault "/etc/keepalived/fault.sh" track_script {
check_haproxy
} virtual_ipaddress {
172.24.8.100 dev eth0
}
}
4.5 编写Keepalived脚本
[root@haproxy_master ~]# vi /etc/keepalived/master.sh
#!/bin/bash
LOGFILE=/var/log/keepalived-mysql-state/log
date >>$LOGFILE
echo "[Master]" >>$LOGFILE
[root@haproxy_master ~]# vi /etc/keepalived/backup.sh
#!/bin/bash
LOGFILE=/var/log/keepalived-mysql-state/log
date >>$LOGFILE
echo "[BACKUP]" >>$LOGFILE
[root@haproxy_master ~]# vi /etc/keepalived/fault.sh
#!/bin/bash
LOGFILE=/var/log/keepalived-mysql-state/log
date >>$LOGFILE
echo "[FAULT]" >>$LOGFILE
[root@haproxy_master ~]# chmod u+x /etc/keepalived/backup.sh
[root@haproxy_master ~]# chmod u+x /etc/keepalived/master.sh
[root@haproxy_master ~]# chmod u+x /etc/keepalived/fault.sh
提示：本环境采用测试脚本，真实环境建议采用自动发送邮件通知运维员的脚本。
4.5 Bakcup节点配置
[root@haproxy_master ~]# scp /etc/keepalived/keepalived.conf 172.24.8.11:/etc/keepalived/keepalived.conf #将配置好的Master节点的配置文件复制到Backup节点
[root@haproxy_slave ~]# vi /etc/keepalived/keepalived.conf
state BACKUP
priority 80
注意：在HAProxy备节点也设置为BACKUP，priority修改为低于HAProxy主角色的优先级即可，同时去掉nopreempt。
[root@haproxy_master ~]# scp /etc/keepalived/*.sh 172.24.8.11:/etc/keepalived/
#将对应的脚本也复制至backup节点。
五 HAProxy部署
5.1 HAProxy安装
[root@haproxy_master ~]# yum -y install haproxy
提示：需要在主备HAProxy节点都安装。
5.2 HAProxy配置
[root@haproxy_master ~]# vi /etc/haproxy/haproxy.cfg
global
log 127.0.0.1 local0 info
chroot /var/lib/haproxy
pidfile /var/run/haproxy.pid
maxconn 4096
user haproxy
group haproxy
daemon
nbproc 1
defaults
mode http
log global
retries 3
timeout connect 5s
timeout client 30s
timeout server 30s
timeout check 2s
frontend www
bind 172.24.8.100:80
mode http
option httplog
option forwardfor
log global acl host_www hdr_dom(host) -i www.lz.com #配置不同域名分发不同后端策略
acl host_static hdr_dom(host) -i static.lz.com
acl host_video hdr_dom(host) -i video.lz.com use_backend server_www if host_www #配置不同域名分发不同后端策略
use_backend server_static if host_static
use_backend server_video if host_video
backend server_www #后端真是服务器
mode http
option redispatch
option abortonclose
balance roundrobin
option httpchk GET /index.html
server webapp1 172.24.8.30:80 weight 6 check inter 2000 rise 2 fall 3
backend server_static #后端真是服务器
mode http
option redispatch
option abortonclose
balance roundrobin
option httpchk GET /index.html
server webapp2 172.24.8.31:80 weight 6 check inter 2000 rise 2 fall 3
backend server_video #后端真是服务器
mode http
option redispatch
option abortonclose
balance roundrobin
option httpchk GET /index.html
server webapp3 172.24.8.32:80 weight 6 check inter 2000 rise 2 fall 3
[root@haproxy_master ~]# scp /etc/haproxy/haproxy.cfg root@172.24.8.11:/etc/haproxy/haproxy.cfg #将配置文件复制至HAProxy备节点
5.3 打开转发
[root@haproxy_master ~]# vi /etc/sysctl.conf
net.ipv4.ip_nonlocal_bind = 1
[root@haproxy_master ~]# sysctl -p
注意：绑定非本机的IP必须在sysctl.conf文件中配置。
六 启动服务
[root@webapp1 ~]# systemctl start httpd
提示：三个节点的httpd服务均启动。
[root@haproxy_master ~]# service haproxy start
提示：必须先启动HAProxy服务，之后启动Keepalived，因为Keepalived会先检测HAProxy服务进程。
[root@haproxy_master ~]# service keepalived start
七 验证测试
7.1 高可用验证
[root@haproxy_master ~]# ip add
[root@haproxy_master ~]# service haproxy stop #停止HAProxy主节点的HAProxy进程
[root@haproxy_master ~]# tail -f /var/log/messages #观察HAProxy主节点日志
[root@haproxy_slave ~]# ip addr #查看备HAProxy节点的IP
结论：通过测试可知当主HAProxy节点服务异常，Keepalived会检测到，同时HAProxy会将vip从主节点移除，备HAProxy会接管。
[root@haproxy_master ~]# service haproxy start
结论：由于配置了非抢占模式，主HAProxy恢复进程之后，依旧由备HAProxy提供服务，vip不会切回至主HAProxy。
7.2 负载均衡测试
主机hosts中添加如下解析：
172.24.8.100 www.lz.com
172.24.8.100 static.lz.com
172.24.8.100 video.lz.com
浏览器分别访问不用的三个域名：