003.Keepalived搭建LVS高可用集群

一基础环境

1.1 IP规划

OS：CentOS 6.8 64位

节点类型	IP规划	主机名	类型
主 Director Server	eth0：172.24.8.10	DR1	公共IP
	eth1：192.168.56.100	心跳	私有IP
	eth0:0：172.24.8.100	无	虚拟IP
主 Director Server	eth0：172.24.8.11	DR2	公共IP
主 Director Server	eth1：192.168.56.101	心跳	私有IP
Real Server 1	eth0：172.24.8.12	rs1	公共IP
Real Server 1	lo:0：172.24.8.100	无	虚拟IP
Real Server 1	eth0：172.24.8.13	rs2	公共IP
Real Server 1	lo:0：172.24.8.100	无	虚拟IP

1.2 架构规划

二高可用LVS负载均衡集群部署

2.1 NTP部署

操作略，具体可参考N01.1.1-常见服务《NTP》。

注意：为了保证集群的稳定性，强烈建议在所有节点均部署NTP同步服务，保证所有时钟一致。

2.2 部署httpd集群

 [root@RServer01 ~]# yum -y install httpd

 [root@RServer01 ~]# service iptables stop

 [root@RServer01 ~]# chkconfig iptables off

 [root@RServer01 ~]# vi /etc/selinux/config

 SELINUX=disabled

 [root@master ~]# setenforce 0			                 #关闭SELinux及防火墙

注意：后端所有Real服务器节点都需要安装，用于模拟测试。

建议：为了测试方便，建议所有节点关闭防火墙和SELinux，若未关闭防火墙也可通过下列方式放通：

 firewall-cmd --permanent–-add-service=keepalived

 firewall-cmd --reload

2.3 安装Keepalived

 [root@lvsmaster ~]# yum -y install gcc gcc-c++ make kernel-devel kernel-tools kernel-tools-libs kernel libnl libnl-devel libnfnetlink-devel openssl-devel wget openssh-clients	        #安装基础环境及依赖

 [root@lvsmaster ~]# ln -s /usr/src/kernels/`uname -r` /usr/src/linux

 [root@lvsmaster ~]# wget http://www.keepalived.org/software/keepalived-1.3.6.tar.gz

 [root@lvsmaster ~]# tar -zxvf keepalived-1.3.6.tar.gz	        #编译安装Keepalived

 [root@lvsmaster ~]# cd keepalived-1.3.6/

 [root@lvsmaster keepalived-1.3.6]# ./configure --prefix=/usr/local/keepalived

 [root@Master keepalived-1.3.9]# make && make install

注意：CentOS6.8安装高于1.3.6版本会出现未知错误。

2.4 添加启动相关服务

 [root@lvsmaster ~]# mkdir /etc/keepalived

 [root@lvsmaster ~]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/

 [root@lvsmaster ~]# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/

 [root@lvsmaster ~]# cp /usr/local/keepalived/sbin/keepalived /usr/sbin/

 [root@lvsmaster ~]# vi /etc/init.d/keepalived		#创建Keepalived启动脚本，如附件

 #!/bin/sh

 #

 # keepalived   High Availability monitor built upon LVS and VRRP

 #

 # chkconfig:   - 86 14

 # description: Robust keepalive facility to the Linux Virtual Server project \

 #              with multilayer TCP/IP stack checks.

 ### BEGIN INIT INFO

 # Provides: keepalived

 # Required-Start: $local_fs $network $named $syslog

 # Required-Stop: $local_fs $network $named $syslog

 # Should-Start: smtpdaemon httpd

 # Should-Stop: smtpdaemon httpd

 # Default-Start:

 # Default-Stop: 0 1 2 3 4 5 6

 # Short-Description: High Availability monitor built upon LVS and VRRP

 # Description:       Robust keepalive facility to the Linux Virtual Server

 #                    project with multilayer TCP/IP stack checks.

 ### END INIT INFO

 # Source function library.

 . /etc/rc.d/init.d/functions

 exec="/usr/sbin/keepalived"

 prog="keepalived"

 config="/etc/keepalived/keepalived.conf"

 [ -e /etc/sysconfig/$prog ] && . /etc/sysconfig/$prog

 lockfile=/var/lock/subsys/keepalived

 start() {

     [ -x $exec ] || exit 5

     [ -e $config ] || exit 6

     echo -n $"Starting $prog: "

     daemon $exec $KEEPALIVED_OPTIONS

     retval=$?

     echo

     [ $retval -eq 0 ] && touch $lockfile

     return $retval

 }

 stop() {

     echo -n $"Stopping $prog: "

     killproc $prog

     retval=$?

     echo

     [ $retval -eq 0 ] && rm -f $lockfile

     return $retval

 }

 restart() {

     stop

     start

 }

 reload() {

     echo -n $"Reloading $prog: "

     killproc $prog -1

     retval=$?

     echo

     return $retval

 }

 force_reload() {

     restart

 }

 rh_status() {

     status $prog

 }

 rh_status_q() {

     rh_status &>/dev/null

 }

 case "$1" in

     start)

         rh_status_q && exit 0

         $1

         ;;

     stop)

         rh_status_q || exit 0

         $1

         ;;

     restart)

         $1

         ;;

     reload)

         rh_status_q || exit 7

         $1

         ;;

     force-reload)

         force_reload

         ;;

     status)

         rh_status

         ;;

     condrestart|try-restart)

         rh_status_q || exit 0

         restart

         ;;

     *)

         echo $"Usage: $0 {start|stop|status|restart|condrestart|try-restart|reload|force-reload}"

         exit 2

 esac

 exit $

 [root@lvsmaster ~]# chmod u+x /etc/rc.d/init.d/keepalived

 [root@lvsmaster ~]# vi /etc/keepalived/keepalived.conf

 ! Configuration File for keepalived

 ……

    smtp_connect_timeout 30

    router_id LVS_Master		#表示运行Keepalived服务器的一个标识

 }

 vrrp_instance VI_1 {

     state MASTER			#指定Keepalived的角色

     interface eth0			#指定HA监测网络的接口

     virtual_router_id 51            #同一个vrrp实例使用唯一的标识，即同一个vrrp_instance下，Master和Backup必须是一致的

     priority 100			#定义优先级，数值越大，优先级越高

     advert_int 1			#设定Mater和Backup负载均衡器之间同步检查时间间隔

     authentication {

         auth_type PASS

         auth_pass 1111

     }

     virtual_ipaddress {

         172.24.8.100		#设置虚拟IP地址

     }

 }

 virtual_server 172.24.8.100 80 {

     delay_loop 6			#运行情况检查时间

     lb_algo rr			#设置负载均衡算法

     lb_kind DR			#设置LVS实现负载均衡的机制，有NAT/DR/TUN

     persistence_timeout 50		#会话保持时间

     protocol TCP 			#指定转发类型

     real_server 172.24.8.12 80 {

         weight 1			#服务节点的权值，数值越大，权值越高

         TCP_CHECK {

         connect_timeout 5		#表示无响应超时时间，单位是秒

         nb_get_retry 3		#表示重试次数

         delay_before_retry 3	#表示重试间隔

         }

     }

 real_server 172.24.8.13 80 {

         weight 1

         TCP_CHECK {

         connect_timeout 5

         nb_get_retry 3

         delay_before_retry 3

      }

 }

 }

 [root@lvsmaster ~]# scp /etc/keepalived/keepalived.conf 172.24.8.11:/etc/keepalived/keepalived.conf

 [root@lvsbackup ~]# vi /etc/keepalived/keepalived.conf

 state BACKUP

 priority 80

注意；备用Director Server上需要修改状态为BACKUP和priority优先级。

2.5 安装IPVS管理工具

 [root@lvsmaster ~]# yum -y install ipvsadm

2.6 配置Real Server节点

在LVS的DR和TUN模式下，用户访问请求到大Real Server后，Real Server的响应报文直接返回给用户，而不需经过Director Server。因此，需要在每个Real Server上配置虚拟VIP地址。

注意：回环接口绑定vip，且禁止arp请求等操作，可通过以下脚本实现：脚本可留言索要。

 [root@RServer01 ~]# vi /etc/init.d/lvsrs

 [root@RServer01 ~]# chmod u+x /etc/init.d/lvsrs

2.7 启动集群

 [root@RServer01 ~]# service httpd start

 [root@RServer01 ~]# chkconfig httpd on

 [root@RServer02 ~]# service httpd start

 [root@RServer02 ~]# chkconfig httpd on

 [root@lvsmaster ~]# service keepalived start

 [root@lvsmaster ~]# chkconfig keepalived on

 [root@lvsbackup ~]# service keepalived start

 [root@lvsbackup ~]# chkconfig keepalived on

 [root@RServer01 ~]# service lvsrs start

 [root@RServer02 ~]# service lvsrs start

三测试集群

3.1 高可用功能测试

停止主Director Server服务器的Keepalived，观察/var/log/messages日志，可知备机会立刻变为MASTER，并且接管主机的虚拟ip资源。重启主Director Server服务器的Keepalived，备机会重新恢复为BACKUP角色。

具体测试略。

3.2 负载均衡测试

 [root@RServer01 ~]# echo 'This is Real Server01!' >>/var/www/html/index.html

 [root@RServer01 ~]# echo 'This is Real Server02!' >>/var/www/html/index.html

然后浏览器访问：http://172.24.8.100，并不断的刷新，能分别看到Server01和Server02即可。

3.3 故障切换测试

 [root@RServer01 ~]# service httpd stop

当关掉其中一个Real Server时，访问VIP，只会显示还处于集群中的web节点。