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
	eth1：192.168.56.101	心跳	私有ip
real server 1	eth0：172.24.8.12	rs1	公共ip
	lo:0：172.24.8.100	无	虚拟ip
real server 1	eth0：172.24.8.13	rs2	公共ip
	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

  1 [root@rserver01 ~]# yum -y install httpd
  2 [root@rserver01 ~]# service iptables stop
  3 [root@rserver01 ~]# chkconfig iptables off
  4 [root@rserver01 ~]# vi /etc/selinux/config
  5 selinux=disabled
  6 [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：

  1 firewall-cmd --permanent–-add-service=keepalived
  2 firewall-cmd --reload

 

2.3 安装keepalived

  1 [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
  2 [root@lvsmaster ~]# ln -s /usr/src/kernels/`uname -r` /usr/src/linux
  3 [root@lvsmaster ~]# wget http://www.keepalived.org/software/keepalived-1.3.6.tar.gz
  4 [root@lvsmaster ~]# tar -zxvf keepalived-1.3.6.tar.gz	        #编译安装keepalived
  5 [root@lvsmaster ~]# cd keepalived-1.3.6/
  6 [root@lvsmaster keepalived-1.3.6]# ./configure --prefix=/usr/local/keepalived
  7 [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

  1 [root@lvsmaster ~]# mkdir /etc/keepalived
  2 [root@lvsmaster ~]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
  3 [root@lvsmaster ~]# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
  4 [root@lvsmaster ~]# cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
  5 [root@lvsmaster ~]# vi /etc/init.d/keepalived		#创建keepalived启动脚本，如附件
  6 #!/bin/sh
  7 #
  8 # keepalived   high availability monitor built upon lvs and vrrp
  9 #
 10 # chkconfig:   - 86 14
 11 # description: robust keepalive facility to the linux virtual server project \
 12 #              with multilayer tcp/ip stack checks.
 13 
 14 ### begin init info
 15 # provides: keepalived
 16 # required-start: $local_fs $network $named $syslog
 17 # required-stop: $local_fs $network $named $syslog
 18 # should-start: smtpdaemon httpd
 19 # should-stop: smtpdaemon httpd
 20 # default-start:
 21 # default-stop: 0 1 2 3 4 5 6
 22 # short-description: high availability monitor built upon lvs and vrrp
 23 # description:       robust keepalive facility to the linux virtual server
 24 #                    project with multilayer tcp/ip stack checks.
 25 ### end init info
 26 
 27 # source function library.
 28 . /etc/rc.d/init.d/functions
 29 
 30 exec="/usr/sbin/keepalived"
 31 prog="keepalived"
 32 config="/etc/keepalived/keepalived.conf"
 33 
 34 [ -e /etc/sysconfig/$prog ] && . /etc/sysconfig/$prog
 35 
 36 lockfile=/var/lock/subsys/keepalived
 37 
 38 start() {
 39     [ -x $exec ] || exit 5
 40     [ -e $config ] || exit 6
 41     echo -n $"starting $prog: "
 42     daemon $exec $keepalived_options
 43     retval=$?
 44     echo
 45     [ $retval -eq 0 ] && touch $lockfile
 46     return $retval
 47 }
 48 
 49 stop() {
 50     echo -n $"stopping $prog: "
 51     killproc $prog
 52     retval=$?
 53     echo
 54     [ $retval -eq 0 ] && rm -f $lockfile
 55     return $retval
 56 }
 57 
 58 restart() {
 59     stop
 60     start
 61 }
 62 
 63 reload() {
 64     echo -n $"reloading $prog: "
 65     killproc $prog -1
 66     retval=$?
 67     echo
 68     return $retval
 69 }
 70 
 71 force_reload() {
 72     restart
 73 }
 74 
 75 rh_status() {
 76     status $prog
 77 }
 78 
 79 rh_status_q() {
 80     rh_status &>/dev/null
 81 }
 82 
 83 
 84 case "$1" in
 85     start)
 86         rh_status_q && exit 0
 87         $1
 88         ;;
 89     stop)
 90         rh_status_q || exit 0
 91         $1
 92         ;;
 93     restart)
 94         $1
 95         ;;
 96     reload)
 97         rh_status_q || exit 7
 98         $1
 99         ;;
100     force-reload)
101         force_reload
102         ;;
103     status)
104         rh_status
105         ;;
106     condrestart|try-restart)
107         rh_status_q || exit 0
108         restart
109         ;;
110     *)
111         echo $"usage: $0 {start|stop|status|restart|condrestart|try-restart|reload|force-reload}"
112         exit 2
113 esac
114 exit $
115 [root@lvsmaster ~]# chmod u+x /etc/rc.d/init.d/keepalived
116 [root@lvsmaster ~]# vi /etc/keepalived/keepalived.conf
117 ! configuration file for keepalived
118 ……
119    smtp_connect_timeout 30
120    router_id lvs_master		#表示运行keepalived服务器的一个标识
121 }
122 
123 vrrp_instance vi_1 {
124     state master			#指定keepalived的角色
125     interface eth0			#指定ha监测网络的接口
126     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
128     priority 100			#定义优先级，数值越大，优先级越高
129     advert_int 1			#设定mater和backup负载均衡器之间同步检查时间间隔
130     authentication {
131         auth_type pass
132         auth_pass 1111
133     }
134     virtual_ipaddress {
135         172.24.8.100		#设置虚拟ip地址
136     }
137 }
138 
139 virtual_server 172.24.8.100 80 {
140     delay_loop 6			#运行情况检查时间
141     lb_algo rr			#设置负载均衡算法
142     lb_kind dr			#设置lvs实现负载均衡的机制，有nat/dr/tun
143     persistence_timeout 50		#会话保持时间
144     protocol tcp 			#指定转发类型
145 
146     real_server 172.24.8.12 80 {
147         weight 1			#服务节点的权值，数值越大，权值越高
148         tcp_check {
149         connect_timeout 5		#表示无响应超时时间，单位是秒
150         nb_get_retry 3		#表示重试次数
151         delay_before_retry 3	#表示重试间隔
152         }
153     }
154 real_server 172.24.8.13 80 {
155         weight 1
156         tcp_check {
157         connect_timeout 5
158         nb_get_retry 3
159         delay_before_retry 3
160      }
161 }
162 }
163 [root@lvsmaster ~]# scp /etc/keepalived/keepalived.conf 172.24.8.11:/etc/keepalived/keepalived.conf
164 [root@lvsbackup ~]# vi /etc/keepalived/keepalived.conf
165 state backup
166 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

  1 [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。

  1 [root@rserver01 ~]# vi /etc/init.d/lvsrs
  2 [root@rserver01 ~]# chmod u+x /etc/init.d/lvsrs

 

2.7 启动集群

  1 [root@rserver01 ~]# service httpd start
  2 [root@rserver01 ~]# chkconfig httpd on
  3 [root@rserver02 ~]# service httpd start
  4 [root@rserver02 ~]# chkconfig httpd on
  5 
  6 [root@lvsmaster ~]# service keepalived start
  7 [root@lvsmaster ~]# chkconfig keepalived on
  8 [root@lvsbackup ~]# service keepalived start
  9 [root@lvsbackup ~]# chkconfig keepalived on
 10 
 11 [root@rserver01 ~]# service lvsrs start
 12 [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

  1 [root@rserver01 ~]# echo 'this is real server01!' >>/var/www/html/index.html
  2 [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

  1 [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。