基于keepalived构建HA集群
一、keepalived简介
1.Keepalived的作用是检测RealServer的健康状态,如果有一台RealServer服务器宕机,Keepalived将检测到,并将宕掉的RealServer服务器从系统中剔除,当RealServer服务器重新恢复正常工作后Keepalived自动将RealServer服务器加入到服务器群中。
2.keeepalived常见模型
<1>主从模型:(主节点修复后服务返回主节点)
定义一个VIP(定义在网卡别名之上)
在vrrp_instance做如下修改:
stateMASTER#从节点为BACKUP
priority101#指定优先级,数字越大优先级越高,主节点的优先级高于从节点
<2>双主模型:
创建两个虚拟路由器,两个节点互为主从
指定两个vrrp_instance互为主从
virtual_router_id不相同
<3>LVS+keepalived
首先配置LVS
配置keepalived,添加虚拟服务,指定lvs模型及调度算法
实战篇
系统环境:centos6.4-i386
yum-yinstallkeepalived
keepalivedi686-1.2.7-3
二、主从模型HA集群
修改主配置文件:vim/etc/keepalived/keepalived.conf
! Configuration File for keepalived global_defs { notification_email { [email protected] [email protected] } notification_email_from [email protected] smtp_connect_timeout 3 smtp_server 127.0.0.1 #邮件发送者为本地主机 router_id LVS_DEVEL } vrrp_script chk_haproxy { script "killall -0 haproxy" interval 1 weight 2 } vrrp_script chk_mantaince_down { script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0" interval 1 weight -2 } vrrp_instance VI_1 { #vrrp实例 interface eth0 state MASTER # 从节点为BACKUP priority 101 # 指定优先级,数字越大优先级越高 virtual_router_id 51 garp_master_delay 1 authentication { auth_type PASS auth_pass password } track_interface { eth1 } virtual_ipaddress { 172.16.15.114/16 dev eth1 label eth1:0 #指定VIP及网卡别名 } track_script { chk_haproxy chk_mantaince_down } notify_master "/etc/keepalived/notify.sh master" notify_backup "/etc/keepalived/notify.sh backup" notify_fault "/etc/keepalived/notify.sh fault" }
notify脚本:
#!/bin/bash vip=172.16.15.114 #指定vip contact='[email protected]' 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 exit 0 ;; *) echo 'Usage: `basename $0` {master|backup|fault}' exit 1 ;; esac
以windows作为客户端访问172.16.15.114
关掉主服务:servicekeepalivedstop
三、双主模型
原理:创建两个虚拟路由器,两个节点互为主从。
! Configuration File for keepalived global_defs { notification_email { [email protected] [email protected] } notification_email_from [email protected] smtp_connect_timeout 3 smtp_server 127.0.0.1 router_id LVS_DEVEL } vrrp_script chk_haproxy { script "killall -0 haproxy" interval 1 weight 2 } vrrp_script chk_mantaince_down { script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0" interval 1 weight 2 } vrrp_instance VI_1 { #实例1 interface eth1 state MASTER # BACKUP for slave routers priority 101 # 100 for BACKUP virtual_router_id 51 garp_master_delay 1 authentication { auth_type PASS auth_pass password } track_interface { eth1 } virtual_ipaddress { #VIP1 172.16.15.115/16 dev eth1 label eth1:1 } track_script { chk_haproxy chk_mantaince_down } notify_master "/etc/keepalived/notify.sh master" notify_backup "/etc/keepalived/notify.sh backup" notify_fault "/etc/keepalived/notify.sh fault" } vrrp_instance VI_2 { #实例2 interface eth1 state BACKUP # BACKUP for slave routers priority 100 # 100 for BACKUP virtual_router_id 52 garp_master_delay 1 authentication { auth_type PASS auth_pass password } track_interface { eth1 } virtual_ipaddress { #VIP2 172.16.15.116/16 dev eth1 label eth1:2 } track_script { chk_haproxy chk_mantaince_down } }
在客户端访问172.16.15.115172.16.15.116
查看IP
四、实现LVS+keepalived(LVS--DR)
1、首先配置LVS负载均衡集群
注:LVS在会后续博文中做详细介绍!!!
添加ipvsadm规则
#yum -y install ipvsadm #安装ipvsadm #ipvsadm #查看ipvsadm信息及规则 #ipvsadm -A -t 172.16.15.117:80 -s rr #指定Director(调度器)
注释:A(添加规则)
-t(指定协议为TCP)
172.16.15.117:80(指定VIP及端口)
-srr(指定调度算法为rr)
#添加real_server
#ipvsadm -a -t 172.16.15.117:80 -r 172.16.15.5 -g #ipvsadm -a -t 172.16.15.117:80 -r 172.16.15.14 -g #ifconfig lo:0 $WEB_VIP netmask 255.255.255.255 broadcast $WEB_VIP #配置VIP,只允许本地回环 # /sbin/route add -host $WEB_VIP dev lo:0 #添加本地路由 #echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore #echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce #echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore #echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce
注释:在此只添加两个节点
-a:添加服务
-r172.16.15.5:指定服务IP
-g:指定lvs模型(默认DR)
2、配置基于keepalived(主从)高可用集群
! Configuration File for keepalived global_defs { notification_email { [email protected] [email protected] } notification_email_from [email protected] smtp_connect_timeout 3 smtp_server 127.0.0.1 router_id LVS_DEVEL } vrrp_script chk_schedown { script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0" interval 2 weight -2 } vrrp_instance VI_1 { interface eth1 state MASTER priority 101 virtual_router_id 51 garp_master_delay 1 authentication { auth_type PASS auth_pass password } track_interface { eth1 } virtual_ipaddress { 172.16.15.117/16 #指定VIP,此处的VIP和lvs的VIP相同,因此不指定网卡 } track_script { chk_schedown } } virtual_server 172.16.15.117 80 { #指定虚拟服务 delay_loop 6 lb_algo rr lb_kind DR persistence_timeout 50 protocol TCP sorry_server 172.16.15.14 80 #错误页面 real_server 172.16.15.5 80 { #指定rserver1 weight 1 HTTP_GET { url { path / status_code 200 #状态码 } connect_timeout 3 nb_get_retry 3 delay_before_retry 3 } } real_server 172.16.15.14 80 { #指定rserver2 weight 1 HTTP_GET { url { path / status_code 200 } connect_timeout 3 #连接超时时间 nb_get_retry 3 #尝试连接次数 delay_before_retry 3 #每次尝试之前等待的时间 } } }
在客户端访问172.16.15.117
转载于:https://blog.51cto.com/dreamwolf/1301660