默认情况下keepalived启动时会去/etc/keepalived目录下找配置文件，将需要的配置文件拷贝到指定位置
# cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/
# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
# cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
# chkconfig mysqld on
# chkconfig keepalived on
LVS安装
ipvsadm下载地址
需要安装以下软件包
# yum install -y libnl* popt*
查看是否加载lvs模块
# modprobe -l |grep ipvs
解压安装
# ln -s /usr/src/kernels/2.6.32-431.5.1.el6.x86_64/ /usr/src/linux
# tar -zxvf ipvsadm-1.26.tar.gz
# make
LVS安装完成，查看当前LVS集群
# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
LVS+Keepalived配置
搭建MySQL主主复制
这里不再赘述，请参考MySQL复制
配置Keepalived
下面是LVS1节点（Keepalived主节点）上的Keepalived配置，LVS2类似
# vim /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs { router_id LVS1 } vrrp_instance VI_1 { state MASTER #指定instance初始状态，实际根据优先级决定.backup节点不一样 interface eth0 #虚拟IP所在网 virtual_router_id 51 #VRID，相同VRID为一个组，决定多播MAC地址 priority 100 #优先级，另一台改为90.backup节点不一样 advert_int 1 #检查间隔 authentication { auth_type PASS #认证方式，可以是pass或ha auth_pass 1111 #认证密码 } virtual_ipaddress { 192.168.1.100 #VIP } } virtual_server 192.168.1.100 3306 { delay_loop 6 #服务轮询的时间间隔 lb_algo wrr #加权轮询调度，LVS调度算法 rr|wrr|lc|wlc|lblc|sh|sh lb_kind DR #LVS集群模式 NAT|DR|TUN，其中DR模式要求负载均衡器网卡必须有一块与物理网卡在同一个网段 #nat_mask 255.255.255.0 persistence_timeout 50 #会话保持时间 protocol TCP #健康检查协议 ## Real Server设置，3306就是MySQL连接端口 real_server 192.168.1.5 3306 { weight 3 ##权重 TCP_CHECK { connect_timeout 3 nb_get_retry 3 delay_before_retry 3 connect_port 3306 } } real_server 192.168.1.6 3306 { weight 3 TCP_CHECK { connect_timeout 3 nb_get_retry 3 delay_before_retry 3 connect_port 3306 } } } |
配置LVS
编写LVS启动脚本/etc/init.d/realserver
#!/bin/sh VIP=192.168.1.100 . /etc/rc.d/init.d/functions case "$1" in # 禁用本地的ARP请求、绑定本地回环地址 start) /sbin/ifconfig lo down /sbin/ifconfig lo up 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 /sbin/sysctl -p >/dev/null 2>&1 /sbin/ifconfig lo:0 $VIP netmask 255.255.255.255 up #在回环地址上绑定VIP，设定掩码，与Direct Server（自身）上的IP保持通信 /sbin/route add -host $VIP dev lo:0 echo "LVS-DR real server starts successfully.n" ;; stop) /sbin/ifconfig lo:0 down /sbin/route del $VIP >/dev/null 2>&1 echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce echo "LVS-DR real server stopped.n" ;; status) isLoOn=`/sbin/ifconfig lo:0 | grep "$VIP"` isRoOn=`/bin/netstat -rn | grep "$VIP"` if [ "$isLoON" == "" -a "$isRoOn" == "" ]; then echo "LVS-DR real server has run yet." else echo "LVS-DR real server is running." fi exit 3 ;; *) echo "Usage: $0 {start|stop|status}" exit 1 esac exit 0 |
将lvs脚本加入开机自启动
# chmod +x /etc/init.d/realserver
# echo "/etc/init.d/realserver" >> /etc/rc.d/rc.local
分别启动LVS和keepalived
# service realserver start
# service keepalived start
注意此时网卡的变化，可以看到虚拟网卡已经分配到了realserver上。
此时查看LVS集群状态，可以看到集群下有两个Real Server，调度算法，权重等信息。ActiveConn代表当前Real Server的活跃连接数
# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.1.100:3306 wrr persistent 50
-> 192.168.1.5:3306 Route 3 4 1
-> 192.168.1.6:3306 Route 3 0 2
此时LVS+Keepalived+MySQL主主复制已经搭建完成。
测试验证
功能性验证
关闭MySQL Server2
# service mysqld stop
在LVS1查看/var/log/messages中关于keepalived日志，LVS1检测到了MySQL Server2宕机，同时LVS集群自动剔除了故障节点
Sep 9 13:50:53 192.168.1.2 Keepalived_healthcheckers[18797]: TCP connection to [192.168.1.6]:3306 failed !!!
Sep 9 13:50:53 192.168.1.2 Keepalived_healthcheckers[18797]: Removing service [192.168.1.6]:3306 from VS [192.168.1.100]:3306
从新启动MySQL Server2后自动将故障节点自动加入LVS集群
Sep 9 13:51:41 192.168.1.2 Keepalived_healthcheckers[18797]: TCP connection to [192.168.1.6]:3306 success.
Sep 9 13:51:41 192.168.1.2 Keepalived_healthcheckers[18797]: Adding service [192.168.1.6]:3306 to VS [192.168.1.100]:3306
关闭LVS1上的Keepalived（模拟宕机操作），查看LVS1上的日志，可以看到Keepalived移出了LVS1上的VIP
Sep 9 14:01:27 192.168.1.2 Keepalived[18796]: Stopping Keepalived v1.2.13 (09/09,2014)
Sep 9 14:01:27 192.168.1.2 Keepalived_healthcheckers[18797]: Removing service [192.168.1.5]:3306 from VS [192.168.1.100]:3306
Sep 9 14:01:27 192.168.1.2 Keepalived_healthcheckers[18797]: Removing service [192.168.1.6]:3306 from VS [192.168.1.100]:3306
Sep 9 14:01:27 192.168.1.2 Keepalived_vrrp[18799]: VRRP_Instance(VI_1) sending 0 priority
Sep 9 14:01:27 192.168.1.2 Keepalived_vrrp[18799]: VRRP_Instance(VI_1) removing protocol VIPs.
同时查看LVS2上日志，可以看到LVS2成为了Master，并接管了VIP
Sep 9 14:11:24 192.168.1.11 Keepalived_vrrp[7457]: VRRP_Instance(VI_1) Transition to MASTER STATE
Sep 9 14:11:25 192.168.1.11 Keepalived_vrrp[7457]: VRRP_Instance(VI_1) Entering MASTER STATE
Sep 9 14:11:25 192.168.1.11 Keepalived_vrrp[7457]: VRRP_Instance(VI_1) setting protocol VIPs.
Sep 9 14:11:25 192.168.1.11 Keepalived_vrrp[7457]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 192.168.1.100
Sep 9 14:11:25 192.168.1.11 Keepalived_healthcheckers[7456]: Netlink reflector reports IP 192.168.1.100 added
Sep 9 14:11:25 192.168.1.11 avahi-daemon[1407]: Registering new address record for 192.168.1.100 on eth0.IPv4.
Sep 9 14:11:30 192.168.1.11 Keepalived_vrrp[7457]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 192.168.1.100
在LVS2上查看LVS集群状态，一切正常。
# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.1.100:3306 wrr persistent 50
-> 192.168.1.5:3306 Route 3 2 0
-> 192.168.1.6:3306 Route 3 1 0
总结
MySQL主主复制是集群的基础，组成Server Array，其中每个节点作为Real Server。
LVS服务器提供了负载均衡的作用，将用户请求分发到Real Server，一台Real Server故障并不会影响整个集群。
Keepalived搭建主备LVS服务器，避免了LVS服务器的单点故障，出现故障时可以自动切换到正常的节点。
