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欢迎跳转到本文的原文链接:/backend/lvs-keepalived-standby/
1. 说明
在《keepalived实现Tomcat服务双机热备》中主要讲述如何安装及配置Keepalived来实现双机热备,主要功能是:MASTER和BACKUP两台服务器处于热备状态,对用户虚拟一个IP,屏蔽底层的真实IP地址,用户通过虚拟IP访问当前的MASTER服务器;当MASTER服务器宕机或者发生其他故障时,BACKUP自动切换为MASTER,这个过程对用户时透明的。
本文主要讲述如何安装ipvsadm、如何配置LVS+Keepalived实现负载均衡和双机热备的功能。功能描述:用户通过虚拟IP访问时,应当会负载均衡到主备服务器上;当然,当MASTER服务器宕机或者发生其他故障时,BACKUP也会自动切换为MASTER。
2. 安装及配置
2.1 安装ipvsadm
首先安装ipvsadm,本人用的版本是ipvsadm-1.24-6。可以去相关网站进行下载ipvsadm-1.24-6.src.rpm。
下面安装ipvsadm:(将ipvsadm-1.24-6.src.rpm放在根目录下)
[~] rpm -ivh ipvsadm-1.24-6.src.rpm[~] cd /usr/src/redhat/SOURCES[SOURCES] tar -zxvf ipvsadm-1.24.tar.gz[SOURCES] uname -r2.6.18-238.el5[SOURCES] ln -s/usr/src/kernels/2.6.18.238.el5-X86_64/ /usr/src/linux[SOURCES] cd ipvsadm-1.24[ipvsadm-1.24] make; make install
2.2 配置keepalived.conf
接着配置keepalived.conf:(具体安装请参考《keepalived实现Tomcat服务双机热备》)
MASTER(10.10.195.53)配置:
global_defs {router_id LVS_DEVEL_1}vrrp_script chk_http_port {script "/opt/tomcat.pid"interval 5weight 2}vrrp_instance VI_1 {state MASTERinterface eth0virtual_router_id 53priority 150advert_int 1authentication {auth_type PASSauth_pass 1111}track_script {chk_http_port}virtual_ipaddress {10.10.195.212 #VIP}}virtual_server 10.10.195.212 8080 {delay_loop 6lb_algo wrrlb_kind DRprotocol TCPreal_server 10.10.195.53 8080 {weight 1TCP_CHECK {connect_timeout 3nb_get_retry 3delay_before_retry 3connect_port 8080}}real_server 10.10.195.190 8080 {weight 1TCP_CHECK {connect_timeout 3nb_get_retry 3delay_before_retry 3connect_port 8080}}}
BACKUP(10.10.195.190)配置:
lobal_defs {router_id LVS_DEVEL_2}vrrp_script chk_http_port {script "/opt/tomcat.pid"interval 5weight 2}vrrp_instance VI_1 {state BACKUPinterface eth0virtual_router_id 53priority 100advert_int 1authentication {auth_type PASSauth_pass 1111}track_script {chk_http_port}virtual_ipaddress {10.10.195.212}}virtual_server 10.10.195.212 8080 {delay_loop 6lb_algo wrrlb_kind DRprotocol TCPreal_server 10.10.195.53 8080 {weight 1TCP_CHECK {connect_timeout 3nb_get_retry 3delay_before_retry 3connect_port 8080}}real_server 10.10.195.190 8080 {weight 1TCP_CHECK {connect_timeout 3nb_get_retry 3delay_before_retry 3connect_port 8080}}}
2.3 LVS脚本配置
两台WEB服务器安装http服务(tomcat)后,创建文件并赋予权限,配置lvs脚本,脚本作用是一直ARP广播,将请求包都由负载均衡lvs服务分配。
主备机的LVS脚本是相同的。虚拟IP(VIP)是10.10.195.212。下面是脚本的代码:
[~] vim /sbin/realdr.sh
#!/bin/bashVIP=10.10.195.211/etc/rc.d/init.d/functionscase "$1" instart)echo "start LVS of REALServer"/sbin/ifconfig lo:0 $VIP broadcast $VIP netmask 255.255.255.255 up# /sbin/route add -host $VIP dev 1o:0echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignoreecho "2" >/proc/sys/net/ipv4/conf/lo/arp_announceecho "1" >/proc/sys/net/ipv4/conf/all/arp_ignoreecho "2" >/proc/sys/net/ipv4/conf/all/arp_announce;;stop)echo "close LVS REALServer"/sbin/ifconfig lo:0 down# /sbin/route del -host $VIP dev lo:0echo "0" >/proc/sys/net/ipv4/conf/lo/arp_ignoreecho "0" >/proc/sys/net/ipv4/conf/lo/arp_announceecho "0" >/proc/sys/net/ipv4/conf/all/arp_ignoreecho "0" >/proc/sys/net/ipv4/conf/all/arp_announce;;status)islothere=`/sbin/ifconfig lo:0 | grep $VIP | wc -l`isrothere=`netstat -rn | grep "lo:0" | grep $VIP | wc -l`# echo $islothere# echo $isrothereif [ $islothere -eq 0 ]thenif [ $isrothere -eq 0 ]thenecho "LVS of REALServer Stoped."elseecho "LVS of REALServer Running."fielseecho "LVS of REALServer Running."fi;;*)echo "Usage:$0{start|stop}"exit 1;;esac
设置LVS脚本权限并运行:
[~] chmod 755 /sbin/realdr.sh[~] /sbin/realdr.sh start
3. 查看
3.1查看虚拟ip相关信息
之后安装并启动keepalived:service keepalived start.
可以通过使用ip addshow命令查看(以MASTER为例):
1: lo: <LOOPBACK,UP,LOWER_UP> mtu16436 qdisc noqueuelink/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00inet 127.0.0.1/8 scope host loinet 10.10.195.211/32 brd 10.10.195.211 scope global lo:02: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP>mtu 1500 qdisc pfifo_fast qlen 1000link/ether 00:0c:29:6b:f2:a8 brd ff:ff:ff:ff:ff:ffinet 10.10.195.53/24 brd 10.10.195.255 scope global eth0inet 10.10.195.211/32 scope global eth0
可以看到lo及eth0上都有虚拟IP地址。
3.2 查看负载均衡状态
在终端输入命令:ipvsadm可以查看。
MASTER(10.10.195.53):
IP Virtual Server version 1.2.1 (size=4096)Prot LocalAddress:Port Scheduler Flags-> RemoteAddress:PortForward Weight ActiveConn InActConnTCP 10.10.195.212:webcache wrr-> 10.10.195.190:webcacheRoute 10 11-> shr:webcacheLocal 10 0
BACKUP(10.10.195.190):
IP Virtual Server version 1.2.1 (size=4096)Prot LocalAddress:Port Scheduler Flags-> RemoteAddress:PortForward Weight ActiveConn InActConnTCP 10.10.195.211:webcache wrr-> server1:webcache Local 10 0-> 10.10.195.53:webcache Route 10 11
4. 测试
如果多次打开浏览器,通过虚拟IP访问网站,应当会负载均衡到两台服务器上。第一次打开一个浏览器并输入http://10.10.195.212:8080/,显示10.10.195.53(190)服务的内容;第二次打开一个浏览器并输入http://10.10.195.212:8080/,显示10.10.195.190(53)服务器的内容。
欢迎跳转到本文的原文链接:/backend/lvs-keepalived-standby/
欢迎支持笔者新作:《深入理解Kafka:核心设计与实践原理》和《RabbitMQ实战指南》,同时欢迎关注笔者的微信公众号:朱小厮的博客。