案例一(haproxy+keepalived高可用负载均衡系统)【转】

时间:2023-03-08 15:34:21
案例一(haproxy+keepalived高可用负载均衡系统)【转】

1.搭建环境描述:

操作系统:

[root@HA-1 ~]# cat /etc/redhat-release

CentOS release 6.7 (Final)

地址规划:

主机名 IP地址 集群角色 虚拟IP
haproxy-server 10.0.0.35 主HAProxyServer 10.0.0.40
haproxy-backup

10.0.0.36

备用HAProxyServer
webapp1 10.0.0.150 Backend Server
webapp2

10.0.0.151

webapp3 10.0.0.152

拓扑结构:

案例一(haproxy+keepalived高可用负载均衡系统)【转】

此结构要实现的功能是:通过HAProxy实现三个站点的负载均衡,即当用户通过域名www.zb.com访问网站时,HAProxy要将请求发送到webapp1主机;当用户通过域名static.zb.com访问网站时,HAProxy要将请求发送到webapp2主机;当用户通过域名video.zb.com访问网站时,HAProxy要将请求发送到webapp3主机;当主HAProxyServer发送故障后,能立刻将负载均衡切换到备用HAProxyServer上。

为了实现HAProxy的高可用功能,这里采用Keepalived作为高可用监控软件。

2.配置HAProxy负载均衡服务器

关于HAProxy的安装,我这里使用yum安装的,就不做详细介绍。haproxy配置文件如下:

global

# to have these messages end up in /var/log/haproxy.log you will

# need to:

#

# 1) configure syslog to accept network log events.  This is done

#    by adding the '-r' option to the SYSLOGD_OPTIONS in

#    /etc/sysconfig/syslog

#

# 2) configure local2 events to go to the /var/log/haproxy.log

#   file. A line like the following can be added to

#   /etc/sysconfig/syslog

#

#    local2.*                       /var/log/haproxy.log

#

log         127.0.0.1 local2

pidfile     /var/run/haproxy.pid

maxconn     4000

user        haproxy

group       haproxy

daemon

nbproc      1

# turn on stats unix socket

#---------------------------------------------------------------------

# common defaults that all the 'listen' and 'backend' sections will

# use if not designated in their block

#---------------------------------------------------------------------

defaults

mode                    http

retries                 3

timeout connect         5s

timeout client          30s

timeout server          30s

timeout check           2s

listen admin_stats

bind 0.0.0.0:19088

mode http

log 127.0.0.1 local0 err

stats refresh 30s

stats uri /haproxy-status

stats realm welcome login\ Haproxy

stats auth admin:admin

stats hide-version

stats admin if  TRUE

#---------------------------------------------------------------------

# main frontend which proxys to the backends

#---------------------------------------------------------------------

frontend www

bind *:80

mode http

option httplog

option forwardfor

log global

acl host_www hdr_dom(host) -i www.zb.com

acl host_static hdr_dom(host) -i static.zb.com

acl host_video hdr_dom(host) -i video.zb.com

use_backend server_www if host_www

use_backend server_static if host_static

use_backend server_video if host_video

#---------------------------------------------------------------------

# static backend for serving up images, stylesheets and such

#---------------------------------------------------------------------

backend server_www

mode http

option redispatch

option abortonclose

balance roundrobin

option httpchk GET /index.html

server web01 10.0.0.150:80 weight 6 check inter 2000 rise 2 fall 3

backend server_static

mode http

option redispatch

option abortonclose

balance roundrobin

option httpchk GET /index.html

server web02 10.0.0.151:80 weight 6 check inter 2000 rise 2 fall 3

backend server_video

mode http

option redispatch

option abortonclose

balance roundrobin

option httpchk GET /index.html

server web03 10.0.0.152:80 weight 6 check inter 2000 rise 2 fall 3

在这个HAProxy配置中,通过ACL规则将三个站点分别转向webapp1、webapp2和webapp3三个服务节点上,这样变相地实现了负载均衡。三个后端实例server_www、server_static和server_video虽然只有一台服务器,但是如果站点访问量增加,可以很容易地增加后端服务器,实现真正的负载均衡。

将haproxy.conf文件复制到备用的haproxy-backup服务器上,然后在主、备HAProxy上依次启动HAProxy服务。

3.配置主、备Keepalived服务器

依次在主、备两个节点上安装Keepalived。我这还是用yum安装,在haproxy-server主机上,keepalived.conf的内容如下:

! Configuration File for keepalived

global_defs {

notification_email {

acassen@firewall.loc

failover@firewall.loc

sysadmin@firewall.loc

}

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 "killall -0 haproxy"

interval 2

}

vrrp_instance HAProxy_HA {

state BACKUP

interface eth0

virtual_router_id 80

priority 100

advert_int 2

nopreempt

authentication {

auth_type PASS

auth_pass aaaa

}

notify_master "/etc/keepalived/mail_notify.sh master"

notify_backup "/etc/keepalived/mail_notify.sh backup"

notify_fault "/etc/keepalived/mail_notify.sh fault"

track_script {

check_haproxy

}

virtual_ipaddress {

10.0.0.40/24 dev eth0

}

}

其中,/etc/keepalived/mail_notify.sh文件是一个邮件通知程序,当keepalived进行Master、Backup、Fault状态切换时,将会发送通知邮件给运维人员,这样可以及时了解高可用集群的运行状态,以便在适当的时候人为介入处理故障。mail_notify.sh文件的内容如下:

#!/bin/bash

#监控keepalived切换状态脚本

IP=`ifconfig | grep 10.0.0|awk '{print $2}'|awk -F ':' '{print $2}'`

echo "${IP} $1 状态被激活,请确认HAProxy服务运行状态!"|mail -s "HAProyx状态切换报警" 11*******11@qq.com

最后,将keepalived.conf文件和mail_notify.sh文件复制到haproxy-backup服务器上对应的位置,然后将keepalived文件中priority值修改为90,由于配置的是不抢占模式,因此,还需要在backup-haproxy服务器上去掉nopreempt选项。

完成所有配置后,分别在haproxy-server和haproxy-backup主机上依次启动HAProxy服务和Keepalived服务。注意,这里一定要先启动HAProxy服务,因为Keepalived服务在启动的时候回自动检测HAProxy服务是否正常,如果发现HAProxy服务没有启动,那么主、备Keepalived将自动进入Fault状态。在依次启动服务后,在正常情况下VIP地址应该运行在haproxy-server服务器上,通过命令“ip a”可以查看VIP是否已经正常加载。

4.测试HAProxy+Keepalived高可用负载均衡集群

高可用的HAProxy负载均衡系统能够实现HAProxy的高可用性、负载均衡特性和故障切换特性。

测试keepalived的高可用功能:

高可用性是通过HAProxy的两个HAProxy Server完成的。为了模拟故障,先将主haproxy-server上面的HAProxy服务停止,接着观察haproxy-server上的keepalived的运行日志,信息如下:

Jul 24 16:04:13 data-1-1 Keepalived_vrrp[25735]: VRRP_Script(check_haproxy) failed

Jul 24 16:04:14 data-1-1 Keepalived_vrrp[25735]: VRRP_Instance(HAProxy_HA) Received higher prio advert

Jul 24 16:04:14 data-1-1 Keepalived_vrrp[25735]: VRRP_Instance(HAProxy_HA) Entering BACKUP STATE

Jul 24 16:04:14 data-1-1 Keepalived_vrrp[25735]: VRRP_Instance(HAProxy_HA) removing protocol VIPs.

Jul 24 16:04:14 data-1-1 Keepalived_healthcheckers[25734]: Netlink reflector reports IP 10.0.0.40 removed

这段日志显示了check_haproxy检测失败后,haproxy-server自动进入了backup状态,同时释放了虚拟IP。由于执行了角色切换,此时mail_notify.sh脚本应该会自动执行并发送状态切换邮件。

然后观察备机haproxy-backup上Keepalived的运行日志,信息如下:

Jul 24 16:04:14 data-1-2 Keepalived_vrrp[25243]: VRRP_Instance(HAProxy_HA) forcing a new MASTER election

Jul 24 16:04:14 data-1-2 Keepalived_vrrp[25243]: VRRP_Instance(HAProxy_HA) forcing a new MASTER election

Jul 24 16:04:16 data-1-2 Keepalived_vrrp[25243]: VRRP_Instance(HAProxy_HA) Transition to MASTER STATE

Jul 24 16:04:18 data-1-2 Keepalived_vrrp[25243]: VRRP_Instance(HAProxy_HA) Entering MASTER STATE

Jul 24 16:04:18 data-1-2 Keepalived_vrrp[25243]: VRRP_Instance(HAProxy_HA) setting protocol VIPs.

Jul 24 16:04:18 data-1-2 Keepalived_healthcheckers[25242]: Netlink reflector reports IP 10.0.0.40 added

Jul 24 16:04:18 data-1-2 Keepalived_vrrp[25243]: VRRP_Instance(HAProxy_HA) Sending gratuitous ARPs on eth0 for 10.0.0.40

Jul 24 16:04:23 data-1-2 Keepalived_vrrp[25243]: VRRP_Instance(HAProxy_HA) Sending gratuitous ARPs on eth0 for 10.0.0.40

从日志中可以看出,主机出现故障后,haproxy-backup立刻检测到,此时,haproxy-backup变成Master角色,并且接管了主机的虚拟IP资源,最后将虚拟IP绑定在eth0设备上。

接着,重新启动主haproxy-server上的haproxy服务,然后观察haproxy-server上的日志状态:

Jul 24 18:22:16 data-1-1 Keepalived_vrrp[30896]: VRRP_Script(check_haproxy) succeeded

Jul 24 18:22:17 data-1-1 Keepalived_vrrp[30896]: VRRP_Instance(HAProxy_HA) Entering BACKUP STATE

从日志输出可知,在HAProxy服务启动后,Keepalived监控程序vrrp_script检测到HAProxy已经正常运行,但是并没有执行切换操作,这是由于Keepalived集群中设置了不抢占模式的缘故。

测试负载均衡功能:

将www.zb.com、static.zb.com、video.zb.com这个三个域名解析到10.0.0.40这个虚拟IP上,然后依次访问网站,如果HAProxy运行正常,并且ACL规则设置正确,这里三个网站应该都能正常访问,如果出现错误,可通过查看HAProxy的运行日志判断哪里出现问题。

转自

案例一(haproxy+keepalived高可用负载均衡系统)-闫利朋的博客-51CTO博客
http://blog.51cto.com/6284444/2149581