HAProxy+KeepAlived实现web服务高可用、动静分离等
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的简介以原理
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:
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。
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。
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
[root@node1 ~]# rpm -q keepalived haproxy keepalived-1.2.7-3.el6.x86_64 haproxy-1.4.24-2.el6.x86_64 ----------------------------------------------- [root@node2 ~]# rpm -q keepalived haproxy keepalived-1.2.7-3.el6.x86_64 haproxy-1.4.24-2.el6.x86_64 [root@node2 ~]#
三、配置haproxy实现动静分离
这里在node1上演示;node2同样的配置:
[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 ------------------------------------------------------------------- #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 ~]#
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:
[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:
[root@node1 ~]# vim /etc/keepalived/notify.sh #!/bin/bash # Author: MageEdu <[email protected]> # 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
[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;
#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 ------------------------------------------------------------------ [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
[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 ---------------------------------------------------------------------- [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 --------------------------------------------------------------------- [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。
如有错误;恳请纠正。
本文出自 “Soul” 博客,请务必保留此出处http://chenpipi.blog.51cto.com/8563610/1405554
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