前言：本文主要讲解keepalived+haproxy，等试验完成，后面会附上keepalived+nginx的思路，原理几乎相同，相信能看懂keepalived+haproxy的朋友，亦能很简单的看懂keepalived+nginx
拓扑：
准备工作：
1）.高可用集群节点基于名称互相访问（两节点都需配置，略）
# vim /etc/sysconfig/network
# vim /etc/hosts
2）.高可用集群节点ssh互信（两节点都需配置）
a.com：
# ssh-keygen -t rsa -P ''
# ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected]
b.com：
# ssh-keygen -t rsa -P ''
# ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected]
3）.高可用集群节点时间同步，推荐使用ntpdate向时间服务器同步
为了简单实验，所以采用date命令同步时间
# date 00:00:00 ; ssh [email protected] 'date 00:00:00'
安装软件：
# yum install -y keepalived haproxy
配置：
1）.修改haproxy配置文件：（a.com节点上操作）
# vim/etc/haproxy/haproxy.cfg
#---------------------------------------------------------------------
# Global settings
#---------------------------------------------------------------------
global
# to have thesemessages end up in /var/log/haproxy.log you will
# need to:
#
# 1) configure syslogto accept network log events. This isdone
# by adding the '-r' option to theSYSLOGD_OPTIONS in
# /etc/sysconfig/syslog
#
# 2) configure local2events to go to the /var/log/haproxy.log
# file. A line like the following can be addedto
# /etc/sysconfig/syslog
#
# local2.* /var/log/haproxy.log
#
log 127.0.0.1 local2 #日志通过rsyslog保存
chroot /var/lib/haproxy
pidfile /var/run/haproxy.pid
maxconn 3000 #最大连接
user haproxy
group haproxy
daemon
# turn on stats unixsocket
stats socket/var/lib/haproxy/stats
#---------------------------------------------------------------------
# common defaults that all the 'listen' and 'backend' sectionswill
# use if not designated in their block
#---------------------------------------------------------------------
defaults
mode http #工作模式为http，有tcp等选择，自行查看man文档
log global #记录日志
option httplog #详细记录http日志
option dontlognull #不记录健康检查的日志信息
option http-server-close #启用服务器端主动关闭
option forwardfor except 127.0.0.0/8 #传递客户端IP
retries 3 #请求重试次数
timeout http-request 10s #http请求超时时间
timeout queue 1m #一个请求在队列里的超时时间
timeout connect 10s #连接服务器超时时间
timeout client 1m #客户端超时时间
timeout server 1m #服务器超时时间
timeout http-keep-alive 10s #持久连接超时时间
timeout check 10s #心跳检测超时时间
maxconn 3000 #最大连接
#---------------------------------------------------------------------
# main frontend which proxys to the backends
#---------------------------------------------------------------------
frontend main *:80
#acl url_static path_beg -i /static /images/javascript /stylesheets
#acl url_static path_end -i .jpg .gif .png.css .js
acl url_www path_end -i .php
use_backend www if url_www #如果上方启用的acl中匹配任意，即使用www的后端服务器
default_backend static #默认请求连接发往static的后端服务器
#---------------------------------------------------------------------
# round robin balancing between the various backends
#---------------------------------------------------------------------
backend static #static后端服务器组定义
balance roundrobin #对static中定义的后端服务器，采用的调度算法为roundrobin轮询
server static1 192.168.43.112:80 check #后端服务器static1的IP，以及做健康状态监测
server static1192.168.43.254:80 check
backend www #www后端服务器组定义
balance roundrobin
server app2 192.168.43.113:80 check
listen stats
bind *:8888 #状态页的访问端口
stats enable #haproxy状态页定义
stats uri /stats #状态页的访问路径
stats realm please\ input\ passwd #提示消息，请输入密码，空格需要用\转义才可显示
stats auth admin:liao #验证用户名：admin |密码：liao
stats admin if TRUE #如果用户名验证成功，则显示管理功能
2）.修改keepalived配置文件
# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
}
smtp_server192.168.200.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_down { #定义脚本chk_down
script "[ -f /etc/keepalived/down ] && exit 1 || exit0" #若目录存在down文件则返回1，不存在返回0
interval 1
weight -5 #若存在down文件则减去权重5
}
vrrp_script chk_haproxy { #定义脚本 chk_haproxy
script "killall -0 haproxy &>/dev/null" #检测haproxy是否正常运行，若正常运行则会返回0，否则返回1,
interval 1 #1秒检测一次
weight -5 #若检测haproxy不是正常运行，那么返回值为1，减去权重5
}
vrrp_instance VI_1 { #第一个虚拟路由
state MASTER #运行为主节点
interface eth0
virtual_router_id 51 #虚拟路由ID为51
priority 100 #主节点权重为100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.43.119/32 brd 192.168.43.119 dev eth0label eth0:0 #在eth0:0端口配置192.168.43.119为虚拟地址
}
track_script { #调用上方定义的检测脚本
chk_down
chk_haproxy
}
notify_master "/etc/keepalived/haproxy.sh master" #若状态变为主节点，则运行haproxy.sh脚本且附带参数master（脚本在下方）
notify_backup "/etc/keepalived/haproxy.sh backup" #若状态变为备节点，则运行haproxy.sh脚本且附带参数backup
notify_fault"/etc/keepalived/haproxy.sh fault"
}
vrrp_instance VI_2 { #虚拟路由器2
state BACKUP #运行为备用节点
interface eth0
virtual_router_id 52 #虚拟路由器ID为52
priority 99 #权重99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.43.120/32 brd 192.168.43.120 dev eth0label eth0:1 #在eth0:1上配置虚拟ip192.168.43.120
}
track_script { #一样需要检测上方定义的脚本
chk_down
chk_haproxy
}
notify_master"/etc/keepalived/haproxy.sh master"
notify_backup"/etc/keepalived/haproxy.sh backup"
notify_fault"/etc/keepalived/haproxy.sh fault"
}
3）.创建上方调用的haproxy.sh脚本
# vim /etc/keepalived/haproxy.sh
#!/bin/bash
case "$1" in
master)
/etc/rc.d/init.d/haproxy start #若传递过来的参数为master，则启动haproxy
;;
backup)
/etc/rc.d/init.d/haproxy restart #若传递过来的参数为backup，则重启haproxy
;;
fault)
/etc/rc.d/init.d/haproxy stop #若传递过来的参数为fault，则关闭haproxy
esac
4）.将配置和脚本文件复制到b.com
# scp/etc/keepalived/keepalived.conf /etc/keepalived/haproxy.sh b.com:/etc/keepalived/
# scp/etc/haproxy/haproxy.cnf b.com:/etc/haproxy
5）.切换到b.com操作，适当修改复制到b.com上的keepalived配置文件（只需修改红色字体内容即可）
# vim/etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
}
smtp_server192.168.200.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_down { #定义脚本chk_down
script "[ -f /etc/keepalived/down ] && exit 1 || exit0" #若目录存在down文件则返回1，不存在返回0
interval 1
weight -5 #若存在down文件则减去权重5
}
vrrp_script chk_haproxy { #定义脚本 chk_haproxy
script "killall -0 haproxy &>/dev/null" #检测haproxy是否正常运行，若正常运行则会返回0，否则返回1,
interval 1 #1秒检测一次
weight -5 #若检测haproxy不是正常运行，那么返回值为1，减去权重5
}
vrrp_instance VI_1 { #第一个虚拟路由
state BACKUP #运行为主节点
interface eth0
virtual_router_id 51 #虚拟路由ID为51
priority 99 #主节点权重为100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.43.119/32 brd 192.168.43.119 dev eth0label eth0:0 #在eth0:0端口配置192.168.43.119为虚拟地址
}
track_script { #调用上方定义的检测脚本
chk_down
chk_haproxy
}
notify_master "/etc/keepalived/haproxy.sh master" #若状态变为主节点，则运行haproxy.sh脚本且附带参数master（脚本在下方）
notify_backup "/etc/keepalived/haproxy.sh backup" #若状态变为备节点，则运行haproxy.sh脚本且附带参数backup
notify_fault"/etc/keepalived/haproxy.sh fault"
}
vrrp_instance VI_2 { #虚拟路由器2
state MASTER #运行为备用节点
interface eth0
virtual_router_id 52 #虚拟路由器ID为52
priority 100 #权重99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.43.120/32 brd 192.168.43.120 dev eth0label eth0:1 #在eth0:1上配置虚拟ip192.168.43.120
}
track_script { #一样需要检测上方定义的脚本
chk_down
chk_haproxy
}
notify_master"/etc/keepalived/haproxy.sh master"
notify_backup"/etc/keepalived/haproxy.sh backup"
notify_fault"/etc/keepalived/haproxy.sh fault"
}
6）.分别在两台节点上给予haproxy.sh脚本执行权限
# chmod +x/etc/keepalived/haproxy.sh ; ssh a.com 'chmod +x /etc/keepalived/haproxy.sh'
启动服务，测试。两节点都正常运行时：
1）.启动服务
# service haproxy start ;ssh a.com 'service haproxy start'
# service keepalived start; ssh a.com 'service keepalived start'
2）.分别查看两个节点日志
a.com
b.com
3）.查看两个节点IP
a.com
b.com
4）.测试调度
测试192.168.43.119，a.com节点
动态资源调度到了192.168.43.113
静态资源轮询调度
测试192.168.43.120，b.com节点
动态资源调度到了192.168.43.113
静态资源轮询调度
测试b.com节点down掉时候，b.com的资源是否迁移到a.com：
1）.停掉b.com的keepalived
# servicekeepalived stop
2）.观察a.com的日志
3）.查看a.com上的IP
4）.访问测试119和120查看是否能正常调度
访问192.168.43.119
静态资源，轮询
访问动态资源，调度到113
访问测试192.168.43.120
静态资源，轮询
访问动态资源，调度到113
测试b.com上线，能否将资源抢夺回来：
1）.启动b.com的keepalived服务
# servicekeepalived start
2）.查看两节点的日志（a.com变为备节点，移除IP。b.com变为主节点，添加IP）
a.com
b.com
3）.访问测试（省略）
至此，keepalived双主模型的高可用haproxy完成。
-----------------------------------------------------------------------------------------------
下面为keepalived+nginx的简单过程
1）.nginx作为主流的web服务器，同样也可以作为反向代理服务器，用于负载均衡调度，代替haproxy，而且性能和haproxy相差无几；
2）.所有配置文件仅仅只需修改几处，即可用作keepalived高可用nignx；
1.修改"/etc/keepalived/keepalived.conf"配置文件。（a.com节点，红色字体即为修改的部分）
# vim/etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
}
smtp_server192.168.200.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_down { #定义脚本chk_down
script "[ -f /etc/keepalived/down ] && exit 1 || exit0" #若目录存在down文件则返回1，不存在返回0
interval 1
weight -5 #若存在down文件则减去权重5
}
vrrp_script chk_nginx { #定义脚本 chk_nginx
script "killall -0 nginx&>/dev/null" #检测nginx是否正常运行，若正常运行则会返回0，否则返回1,
interval 1 #1秒检测一次
weight -5 #若检测nginx不是正常运行，那么返回值为1，减去权重5
}
vrrp_instance VI_1 { #第一个虚拟路由
state MASTER #运行为主节点
interface eth0
virtual_router_id 51 #虚拟路由ID为51
priority 100 #主节点权重为100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.43.119/32 brd 192.168.43.119 dev eth0label eth0:0 #在eth0:0端口配置192.168.43.119为虚拟地址
}
track_script { #调用上方定义的检测脚本
chk_down
chk_nginx
}
notify_master"/etc/keepalived/nginx.shmaster" #若状态变为主节点，则运行haproxy.sh脚本且附带参数master（脚本在下方）
notify_backup "/etc/keepalived/nginx.shbackup" #若状态变为备节点，则运行haproxy.sh脚本且附带参数backup
notify_fault "/etc/keepalived/nginx.sh fault"
}
vrrp_instance VI_2 { #虚拟路由器2
state BACKUP #运行为备用节点
interface eth0
virtual_router_id 52 #虚拟路由器ID为52
priority 99 #权重99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.43.120/32 brd 192.168.43.120 dev eth0label eth0:1 #在eth0:1上配置虚拟ip192.168.43.120
}
track_script { #一样需要检测上方定义的脚本
chk_down
chk_nginx
}
notify_master "/etc/keepalived/nginx.sh master"
notify_backup "/etc/keepalived/nginx.sh backup"
notify_fault "/etc/keepalived/nginx.sh fault"
}
2.创建/etc/keepalived/nginx.sh脚本（记得给予nginx.sh执行权限chmod +x nginx.sh）
脚本1
# vim /etc/keepalived/nginx.sh
#!/bin/bash
#nginx script
#我的nginx为编译安装，/etc/rc.d/目录下无服务脚本，使用此脚本。
case "$1" in
master)
/usr/local/nginx/sbin/nginx #启动nginx
;;
backup)
/usr/local/nginx/sbin/nginx -s stop #先停止nginx
/usr/local/nginx/sbin/nginx #再启动nginx，保证nginx无论主备节点都处在运行态，让killall -0 nginx检测成功
;;
fault)
/usr/local/nginx/sbin/nginx -s stop
;;
esac
脚本2
# vim /etc/keepalived/nginx.sh
#!/bin/bash
#nginx script
#rpm包安装的nginx脚本
case "$1" in
master)
/etc/rc.d/init.d/nginx start
;;
backup)
/etc/rc.d/init.d/nginx restart
;;
fault)
/etc/rc.d/init.d/nginx stop
;;
esac
3.配置nginx
# vim/etc/nginx/nginx.conf
http {
include mime.types;
default_type application/octet-stream;
#log_format main '$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;
#tcp_nopush on;
#keepalive_timeout 0;
keepalive_timeout 65;
#gzip on;
upstream staticserver { #设置一个服务器组，不加权重为rr调度算法，加权重为wrr调度算法
server 192.168.43.112 weight 1;
server 192.168.43.254 weight 1;
#ip_hash; #加上ip_hash即为源地址hash算法，在此处没使用用，所以注释了
}
server {
listen 80;
server_name www.a.com;
#charset koi8-r;
#access_log logs/host.access.log main;
#location~* \.php$ { #注释掉的动态内容调度，若想做动静分离的可以使用
# proxy_pass http://192.168.43.113:80;
#}
location / {
# root /var/www/html;
index index.php index.html index.htm;
proxy_pass http://staticserver; # 使用反向代理，将用户请求调度到staticserver中定义的后端服务器
}
}
4.将所有上方配置的文件复制到b.com
# scp/etc/keepalived/keepalived.conf b.com:/etc/keepalived/
# scp/etc/nginx/nginx.conf b.com:/etc/nginx/
# scp/etc/keepalived/nginx.sh b.com:/etc/keepalived/
5.切换到b.com操作，修改一下复制过来的keepalived.conf配置文件（红色字体为修改部分）
# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
}
smtp_server192.168.200.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_down { #定义脚本chk_down
script "[ -f /etc/keepalived/down ] && exit 1 || exit0" #若目录存在down文件则返回1，不存在返回0
interval 1
weight -5 #若存在down文件则减去权重5
}
vrrp_script chk_nginx { #定义脚本 chk_nginx
script "killall -0 nginx&>/dev/null" #检测nginx是否正常运行，若正常运行则会返回0，否则返回1,
interval 1 #1秒检测一次
weight -5 #若检测nginx不是正常运行，那么返回值为1，减去权重5
}
vrrp_instance VI_1 { #第一个虚拟路由
state BACKUP #运行为备用节点
interface eth0
virtual_router_id 51 #虚拟路由ID为51
priority 99 #主节点权重为99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.43.119/32 brd 192.168.43.119 dev eth0label eth0:0 #在eth0:0端口配置192.168.43.119为虚拟地址
}
track_script { #调用上方定义的检测脚本
chk_down
chk_nginx
}
notify_master "/etc/keepalived/nginx.shmaster" #若状态变为主节点，则运行haproxy.sh脚本且附带参数master（脚本在下方）
notify_backup "/etc/keepalived/nginx.shbackup" #若状态变为备节点，则运行haproxy.sh脚本且附带参数backup
notify_fault "/etc/keepalived/nginx.sh fault"
}
vrrp_instance VI_2 { #虚拟路由器2
state MASTER #运行为主节点
interface eth0
virtual_router_id 52 #虚拟路由器ID为52
priority 100 #权重100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.43.120/32 brd 192.168.43.120 dev eth0label eth0:1 #在eth0:1上配置虚拟ip192.168.43.120
}
track_script { #一样需要检测上方定义的脚本
chk_down
chk_nginx
}
notify_master "/etc/keepalived/nginx.sh master"
notify_backup "/etc/keepalived/nginx.sh backup"
notify_fault "/etc/keepalived/nginx.sh fault"
}
3）.此时配置应该完成，在此就不做测试了