大致规划:
主机 | IP | 描述 |
VIP | 192.168.0.222 | 对外提供高可用IP |
haproxy+keepalived (node1) | 192.168.0.111 |
haproxy为后端两台WEB服务的做动静分离;keepalived为haproxy做高可用。 |
haproxy+keepalived (node2) | 192.168.0.112 | |
WEB (node3) | 192.168.0.113 | 提供静态请求响应 |
Apache+PHP+MySQL (node4) | 192.168.0.114 | 提供动态请求响应 |
一、KeepAlived的简介及原理
Keepalived的作用是检测web服务器的状态,如果有一台web服务器死机,或工作出现故障,Keepalived将检测到,并将有故障的web服务器从系统中剔除,当web服务器工作正常后Keepalived自动将web服务器加入到服务器群中,这些工作全部自动完成,不需要人工干涉,需要人工做的只是修复故障的web服务器。
Layer3,4&7工作在IP/TCP协议栈的IP层,TCP层,及应用层,原理分别如下:
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Layer3:Keepalived使用Layer3的方式工作式时,Keepalived会定期向服务器群中的服务器发送一个ICMP的数据包(既我们平时用的Ping程序),如果发现某台服务的IP地址没有激活,Keepalived便报告这台服务器失效,并将它从服务器群中剔除,这种情况的典型例子是某台服务器被非法关机。Layer3的方式是以服务器的IP地址是否有效作为服务器工作正常与否的标准。在本文中将采用这种方式。
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Layer4:如果您理解了Layer3的方式,Layer4就容易了。Layer4主要以TCP端口的状态来决定服务器工作正常与否。如web server的服务端口一般是80,如果Keepalived检测到80端口没有启动,则Keepalived将把这台服务器从服务器群中剔除。
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Layer7:Layer7就是工作在具体的应用层了,比Layer3,Layer4要复杂一点,在网络上占用的带宽也要大一些。Keepalived将根据用户的设定检查服务器程序的运行是否正常,如果与用户的设定不相符,则Keepalived将把服务器从服务器群中剔除。
--引用百度百科
二、安装相关软件
WEB和LAMP搭建这里不做赘述;安装完成后可以测试是否正常访问。
测试两台机器正常访问。
为node1和node2各自安装keepalived和haproxy;为了简便;yum安装即可
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[root@node1 ~] # rpm -q keepalived haproxy
keepalived - 1.2 . 7 - 3.el6 .x86_64
haproxy - 1.4 . 24 - 2.el6 .x86_64
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[root@node2 ~] # rpm -q keepalived haproxy
keepalived - 1.2 . 7 - 3.el6 .x86_64
haproxy - 1.4 . 24 - 2.el6 .x86_64
[root@node2 ~] #
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三、配置haproxy实现动静分离
这里在node1上演示;node2同样的配置:
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[root@node1 ~] # vim /etc/haproxy/haproxy.cfg
#这里对应global段和default段不做任何修改;但是日志需要在global段开启; #其余的全部注释;任何重新添加以下内容; #具体含义上一篇以做解释;这里就不做详细介绍 frontend web bind * : 80
acl url_static path_beg - i / static / images / javascript / stylesheets
acl url_static path_end - i .jpg .gif .png .css .js .html .htm
acl url_dynamic path_end - i .php
use_backend static if url_static
use_backend dynamic if url_dynamic
default_backend static
backend static balance roundrobin
server node3 192.168 . 0.113 : 80 check
backend dynamic balance roundrobin
server node4 192.168 . 0.114 : 80 check
listen stats mode http
bind * : 1234
stats enable
stats refresh 3s
stats hide - version
stats uri / admin?stats
stats realm HAProxy\ Statistics
stats auth admin:haproxy
stats admin if TRUE
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#复制一份到node2即可;各自启动haproxy [root@node1 ~] # scp /etc/haproxy/haproxy.cfg node2:/etc/haproxy/
haproxy.cfg 100 % 3896 3.8KB / s 00 : 00 [root@node1 ~] #
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查看stats信息:
如后端有多台机器;则可以实现负载均衡;这里未做实例。
四、配置keepalived实现haproxy的高可用
同样在node1上配置;但是node2需要更改两个地方:
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[root@node1 ~] # vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs { #全局配置
notification_email {
root@localhost #接受邮件方
}
notification_email_from soul@localhost #发件人
smtp_server 127.0 . 0.1 #邮件服务器
smtp_connect_timeout 30 #超时时长
router_id LVS_DEVEL #ID;随意即可
} vrrp_script chk_down { #添加监控规则
script "[[ -f /root/down ]] && exit 1 || exit 0"
#上面说明如果在/roo/下有down文件;就失败;转移到从上;否则正常 interval 1 #多久监控一次
weight 2 #权重
} vrrp_script chk_haproxy { #监控haproxy服务的
script "pidof haproxy &> /dev/null && exit 0 || exit 1"
interval 1
weight 2
} vrrp_instance VI_1 { #添加一个实例
state MASTER #定义主从 #注意node2从的上为BACKUP
interface eth0 #网络接口
virtual_router_id 222 #虚拟路由ID;根据该ID生成虚拟MAC;保证其唯一性
priority 100 #优先级别;BACKUP要低于MASTER
advert_int 1 #心跳广播间隔
authentication { #认证
auth_type PASS #明文认证
auth_pass 1111 #password
}
virtual_ipaddress { #虚拟IP
192.168 . 0.222
}
track_script { #脚本追踪;生效上述定义脚本
chk_down
chk_haproxy
}
notify_master "/etc/keepalived/notify.sh master" #邮件通知
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
} #更改以上信息;其余配置文件中的信息全部注释即可 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
#复制一份到node2;根据上述描述进行更改 |
提供haproxy脚本:
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[root@node1 ~] # vim /etc/keepalived/notify.sh
#!/bin/bash # Author: MageEdu <linuxedu@foxmail.com> # description: An example of notify script # vip = 192.168 . 0.222
contact = 'root@localhost'
notify() { #定义发送邮件格式等信息
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) #根据参数进行执行对应命令
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 #完成后复制一份到node2即可 #启动keepalived即可 |
五、测试haproxy的高可用
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[root@node1 ~] # ip a
1 : lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link / loopback 00 : 00 : 00 : 00 : 00 : 00 brd 00 : 00 : 00 : 00 : 00 : 00
inet 127.0 . 0.1 / 8 scope host lo
inet6 :: 1 / 128 scope host
valid_lft forever preferred_lft forever
2 : eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000
link / ether 00 : 0c : 29 : 5e : 1e : 4f brd ff:ff:ff:ff:ff:ff
inet 192.168 . 0.111 / 16 brd 192.168 . 255.255 scope global eth0
inet 192.168 . 0.222 / 32 scope global eth0
inet6 fe80:: 20c : 29ff :fe5e: 1e4f / 64 scope link
valid_lft forever preferred_lft forever
#查看虚拟IP目前在node1上; |
测试访问正常;下面down掉node1看下;
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#由于配置文件定义了一个down的脚本;直接建立文件即可 [root@node1 ~] # touch down
[root@node1 ~] # ip a
1 : lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link / loopback 00 : 00 : 00 : 00 : 00 : 00 brd 00 : 00 : 00 : 00 : 00 : 00
inet 127.0 . 0.1 / 8 scope host lo
inet6 :: 1 / 128 scope host
valid_lft forever preferred_lft forever
2 : eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000
link / ether 00 : 0c : 29 : 5e : 1e : 4f brd ff:ff:ff:ff:ff:ff
inet 192.168 . 0.111 / 16 brd 192.168 . 255.255 scope global eth0
inet6 fe80:: 20c : 29ff :fe5e: 1e4f / 64 scope link
valid_lft forever preferred_lft forever
You have new mail in / var / spool / mail / root #这里也提示有邮件信息
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[root@node2 ~] # ip a
1 : lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link / loopback 00 : 00 : 00 : 00 : 00 : 00 brd 00 : 00 : 00 : 00 : 00 : 00
inet 127.0 . 0.1 / 8 scope host lo
inet6 :: 1 / 128 scope host
valid_lft forever preferred_lft forever
2 : eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link / ether 00 : 0c : 29 :df: 70 :b6 brd ff:ff:ff:ff:ff:ff
inet 192.168 . 0.112 / 16 brd 192.168 . 255.255 scope global eth0
inet 192.168 . 0.222 / 32 scope global eth0
#测试已转移到node2上 |
同时测试页面也是正常的。
测试haproxy脚本是否能够执行
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[root@node1 ~] # service haproxy stop
Stopping haproxy: [ OK ] [root@node1 ~] # ip a
1 : lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link / loopback 00 : 00 : 00 : 00 : 00 : 00 brd 00 : 00 : 00 : 00 : 00 : 00
inet 127.0 . 0.1 / 8 scope host lo
inet6 :: 1 / 128 scope host
valid_lft forever preferred_lft forever
2 : eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000
link / ether 00 : 0c : 29 : 5e : 1e : 4f brd ff:ff:ff:ff:ff:ff
inet 192.168 . 0.111 / 16 brd 192.168 . 255.255 scope global eth0
inet6 fe80:: 20c : 29ff :fe5e: 1e4f / 64 scope link
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[root@node2 ~] # ip a
1 : lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link / loopback 00 : 00 : 00 : 00 : 00 : 00 brd 00 : 00 : 00 : 00 : 00 : 00
inet 127.0 . 0.1 / 8 scope host lo
inet6 :: 1 / 128 scope host
valid_lft forever preferred_lft forever
2 : eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link / ether 00 : 0c : 29 :df: 70 :b6 brd ff:ff:ff:ff:ff:ff
inet 192.168 . 0.112 / 16 brd 192.168 . 255.255 scope global eth0
inet 192.168 . 0.222 / 32 scope global eth0
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[root@node1 ~] # tail -5 /var/log/messages
May 2 18 : 25 : 10 node1 Keepalived_vrrp[ 5331 ]: VRRP_Script(chk_haproxy) failed
May 2 18 : 25 : 10 node1 Keepalived_vrrp[ 5331 ]: VRRP_Instance(VI_1) Received higher prio advert
May 2 18 : 25 : 10 node1 Keepalived_vrrp[ 5331 ]: VRRP_Instance(VI_1) Entering BACKUP STATE
May 2 18 : 25 : 10 node1 Keepalived_vrrp[ 5331 ]: VRRP_Instance(VI_1) removing protocol VIPs.
May 2 18 : 25 : 10 node1 Keepalived_healthcheckers[ 5330 ]: Netlink reflector reports IP 192.168 . 0.222 removed
#可以查看系统日志也记录详细信息 #测试启动haproxy后;虚拟IP会自动转回。 |
到此;HAProxy+KeepAlived配置以全部完成;相关功能也都已测试成功。