keepalived + haproxy 实现web 双主模型的高可用负载均衡
1、本文的架构图：http://s3.运维网.com/wyfs02/M00/25/90/wKioL1Nki0jiTqeUAAE35qbWq7g043.jpg
阐述各服务器用途：
1、haproxy在本构架中实现的是：负载均衡
2、keepalived实现对haproxy的高可用
3、apache static 实现静态页面的访问
4、aoache dynamic实现动态页面的访问，图中有两个是实现负载均衡的
配置各功能模块：
一、配置haproxy和keepalived
验证：
1、当一台keepalived宕机后，VIP会不会转移到另外一台服务器
2、当一台haproxy服务出故障，VIP会不会转移到另外一台服务器
注意：
那如果keepalived宕机了，haproxy服务还正常运行，我们要不要让另外一台服务器把VIP夺过去呢？
理论上来讲：最好不要，但是我们的keepalived中的脚本监控着haproxy的进程，keepalived宕机之后，就无从得知haproxy的健康状态，也不能决定自己的优先权priority降不降低了。所以，理论上来讲最好不要，但是实际中光靠keepalived是做不到的。
配置：
1、给两台服务器分别安装上keepalived
# yum -y install keepalived
2、配置keepalived
# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost 配置服务状态变化发送邮件到哪个地址
}
notification_email_from kaadmin@localhost
smtp_server 127.0.0.1 给哪个smtp服务器发邮件
smtp_connect_timeout 30 联系上面smtp服务器30秒联系不上，就超时
router_id LVS_DEVEL
}
vrrp_script chk_haproxy { 本脚本是用来检测该服务器上haproxy服务的健康状态的
script "killall -0 haproxy"
interval 1
weight -2
}
vrrp_instance VI_1 {
state MASTER 这太服务器为主的keepalived
interface eth0 通过eth0网卡广播
virtual_router_id 200虚拟路由id要改，如果在一个局域网中有多个keepalived集群
priority 100 优先级
advert_int 1
authentication {
auth_type PASS
auth_pass 11112222
}
track_script {
chk_haproxy
}
virtual_ipaddress {
192.168.1.200 本机的虚拟IP
}
notify_master "/etc/keepalived/notify.sh master" 各不用状态下运行的脚本
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
vrrp_instance VI_2 { 另外一台主keepalived的从
state BACKUP
interface eth0
virtual_router_id 57
priority 99 设置要比另外一台主keepalived的优先级低
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_mantaince_down
}
virtual_ipaddress {
192.168.1.201
}
} 3、写keepalived处在不同状态下所运行的脚本
#!/bin/bash
# Author: MageEdu
# description: An example of notify script
#
vip=192.168.1.200
contact='root@localhost'
notify() {
mailsubject="`hostname` to be $1: $vip floating"
mailbody="`date '+%F %H:%M:%S'`: vrrp transition, `hostname` changed to be $1"
echo $mailbody | mail -s "$mailsubject" $contact
}
case "$1" in
master)
notify master
/etc/rc.d/init.d/haproxy start
exit 0
;;
backup)
notify backup
/etc/rc.d/init.d/haproxy stop
exit 0
;;
fault)
notify fault
/etc/rc.d/init.d/haproxy stop
exit 0
;;
*)
echo 'Usage: `basename $0` {master|backup|fault}'
exit 1
;;
esac
给脚本以执行权限：
chmod+x/etc/keepalived/notify.sh
4、配置haproxy
因为要实现动静分离，那么我们在配置文件中，就要定义动态资源静态资源转移到不同的服务上去
# yum -y install haproxy安装haproxy
# vim /etc/haproxy/haproxy.cfg
#
log 127.0.0.1 local2
chroot /var/lib/haproxy
pidfile /var/run/haproxy.pid
maxconn 4000
user haproxy
group haproxy
daemon
# turn on stats unix socket
stats socket /var/lib/haproxy/stats
#---------------------------------------------------------------------
# common defaults that all the 'listen' and 'backend' sections will
# use if not designated in their block
#---------------------------------------------------------------------
defaults
mode http 指定haproxy工作模式为http
log global
option httplog
option dontlognull
option http-server-close 当客户端超时时，允许服务端断开连接
option forwardfor except 127.0.0.0/8在http的响应头部加入forwardfor
option redispatch #在使用了基于cookie的会话保持的时候，通常加这么一项，一旦后端某一server宕机时，能够将其会话重新派发到其它的upstream servers
retries 3
timeout http-request 10s
timeout queue 1m
timeout connect 10s
timeout client 1m
timeout server 1m
timeout http-keep-alive 10s
timeout check 10s
maxconn 3000
#---------------------------------------------------------------------
# main frontend which proxys to the backends
#---------------------------------------------------------------------
frontendmain *:80前端代理
acl url_static path_beg -i /static /images /javascript /stylesheets
acl url_static path_end -i .jpg .gif .png .css .js
acl url_dynamic path_end -i .php
use_backend static if url_static
default_backend dynamic
#---------------------------------------------------------------------
# static backend for serving up images, stylesheets and such
#---------------------------------------------------------------------
backend static 后端的静态请求响应
balance roundrobin
server static 192.168.1.100:80 inter 3000 rise 2 fall 3 check maxconn 5000
#---------------------------------------------------------------------
# round robin balancing between the various backends
#---------------------------------------------------------------------
backend dynamic 后端的动态请求响应
balance roundrobin
serverdynamic1 192.168.1.101:80 inter 3000 rise 2 fall 3 check maxconn 5000
serverdynamic2 192.168.1.102:80 inter 3000 rise 2 fall 3 check maxconn 5000
listen statistics
mode http
bind *:8080
~ stats enable
stats auth admin:admin
stats uri /admin?stats 指定URI的访问路径
stats admin if TRUE
stats hide-version
stats refresh 5s
acl allow src 192.168.0.0/24 定义访问控制列表
tcp-request content accept if allow
tcp-request content reject
5、配置另外一台haproxy服务器
因为两台服务器的配置大体相同，我们就直接讲以上配置好的复制文件和脚本文件都传到这台haproxy服务器上，做下修就可以了
# scp /etc/keepalived/keepalived.conf root@192.168.1.121:/etc/keepalived/
root@192.168.1.121's password:
keepalived.conf 100% 4546 4.4KB/s 00:00
# scp /etc/keepalived/notify.sh root@192.168.1.121:/etc/keepalived/
root@192.168.1.121's password:
notify.sh 100%751 0.7KB/s 00:00
# scp /etc/haproxy/haproxy.cfg root@192.168.1.121:/etc/haproxy/
root@192.168.1.121's password:
haproxy.cfg 100% 3529 3.5KB/s 00:00
传输完成，接着来配置 /etc/keepalived/keepalived.conf因为两个节点上的/etc/haproxy/haproxy.cfg相同不用更改
interface eth0
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from kaadmin@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_haproxy {
script "killall -0 haproxy"
interval 1
weight -2
}
vrrp_instance VI_1 {
state BACKUP 这台把master改成 backup
interface eth0
virtual_router_id 200
priority 99 优先级调的比上一个低
advert_int 1
authentication {
auth_type PASS
auth_pass 11112222
}
track_script {
chk_haproxy
}
virtual_ipaddress {
192.168.1.200
}
}
vrrp_instance VI_2 {
state MASTER 本台的这个要调成MASTER，上个是backup
interface eth0
virtual_router_id 57
priority 100 这个优先级也要高于上个
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.201
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
} 注意：
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
3个状态分别要执行的脚本，只能放在 MASTER中，原因是：因为是互为主从，每个主的都会有个另外一个主的从，如果
把这 “3个状态执行脚本” 写入到从的区域中，那么另外一个主的从状态就会执行这个脚本，因为就会停掉所要高可用的
程序，这就造成了，两个VIP全部转移到其中一个服务器上去。
我们来验证下，如果keepalived和haproxy分别宕机，vip会不会转移：
在两个节点上都启动 keepalived和haproxy服务
# service haproxy start
Starting haproxy:
# service keepalived start
Starting keepalived:
以下为正常情况：
keepalived 1：
http://s3.运维网.com/wyfs02/M00/25/90/wKiom1Nkl9uBLSLkAAI7Nv82x7o994.jpg
keepalived 2：
http://s3.运维网.com/wyfs02/M02/25/90/wKioL1Nkl--RJs-GAAHu-Fe95vg162.jpg
我们来模拟让第一个haproxy停止掉，再看下，VIP会不会全到 keepalived 2上面去：
# service haproxy stop
Stopping haproxy:
查看keepalived 1 和 keepalived 2
http://s3.运维网.com/wyfs02/M01/25/91/wKioL1NksZLBURk8AAH68TIiVaw151.jpg
http://s3.运维网.com/wyfs02/M02/25/91/wKioL1NksbmgAwBPAAGZbYr2wF4250.jpg
看，都过来了。。。。
验证负载均衡很动静分离
我们给3个web服务不同的网页
1、给apache static一个静态页面，来验证如果请求的不是以 .php结尾的网页文件都定向到这太服务器上来
2、给apache dynamic 1 、2 分别两个 index.php ，实现对动态网页的负载均衡
我们给apache static 一个符合-i .jpg .gif .png .css .js的网页，就给个图片网页吧
apache static
scp 1.png root@192.168.1.100:/var/www/html
apache dynamic 1
vim /var/www/html/index.php
192.168.1.101
apache dynamic 2
vim /var/www/html/index.php
192.168.1.102
1、我们来请求 1.png 结尾的静态文件
http://s3.运维网.com/wyfs02/M02/25/91/wKiom1Nkw6uDu_vyAAHCiPEKG6g430.jpg
2、我们来请求 .php结尾的页面
http://s3.运维网.com/wyfs02/M02/25/91/wKioL1NkxHDg_K8DAAFLVYOf_d4414.jpg
http://s3.运维网.com/wyfs02/M00/25/91/wKioL1NkxIfym9afAAE52TC8wJ8462.jpg
如此看来，已经对以.php的动态页面做了负载均衡了
我们再通过 192.168.1.201 这个虚拟 ip 访问试试：
http://s3.运维网.com/wyfs02/M00/25/91/wKiom1NkxeKzjSWPAAFM55WLzgs165.jpg
http://s3.运维网.com/wyfs02/M02/25/91/wKioL1Nkxe-jm0ZaAAEqNN02zgU592.jpg
由此看来，也实现了双主模型了，两个haproxy同时可以服务了。。。
3、我们来看看状态页面
http://s3.运维网.com/wyfs02/M02/25/91/wKiom1Nkx9_B57xfAAEctjJMZnc262.jpg
http://s3.运维网.com/wyfs02/M01/25/91/wKioL1Nkx8nz0IfTAAEa74C_zWI937.jpg
http://s3.运维网.com/wyfs02/M02/25/91/wKioL1Nkx9iAeZsaAAeekRUkLfg471.jpg
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