LVS+Keepalived 介绍 LVS LVS 是 Linux Virtual Server 的简写,意即 Linux 虚拟服务器,是一个虚拟的服务器集群系统。本项目在 1998 年 5 月由章文嵩博士成立,是中国国内最早出现的自由软件项目之一。目前有三种 IP 负载均衡技术(VS/NAT、VS/TUN 和 VS/DR); 十种调度算法(rrr|wrr|lc|wlc|lblc|lblcr|dh|sh|sed|nq)。
Keepalvied Keepalived 在这里主要用作 RealServer 的健康状态检查以及 LoadBalance 主机和 BackUP 主机之间 failover 的实现
一、LVS+Keepalived负载均衡主备架构
I. 网站负载均衡拓朴图
(略)
IP 信息清单: 名称 IP
II.安装ipvsadm和keepalived软件包
ipvsadm: http://www.linuxvirtualserver.org/software/kernel-2.6/ipvsadm-1.24.tar.gz
keepalived:http://www.keepalived.org/software/keepalived-1.1.15.tar.gz
下载后建议统一放置在/usr/local/src/lvs
#uname -r??
2.6.18-53.el5PAE?? //查看内核版本??
#ln -s /usr/src/kernels/2.6.18-53.el5PAE-i686/??/usr/src/linux??//防止报错??
#tar zxvf ipvsadm-1.24.tar.gz??
#cd ipvsadm-1.24??
#make && make install??
#find / -name ipvsadm??# 查看ipvsadm的位置??
#tar zxvf keepalived-1.1.15.tar.gz??
#cd keepalived-1.1.15??
#./configure??&& make && make install??
#find / -name keepalived??# 查看keepalived位置??????????????????
#cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/??
#cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/??
#mkdir /etc/keepalived??
#cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/??
#cp /usr/local/sbin/keepalived /usr/sbin/??
#service keepalived start|stop???? #做成系统启动服务方便管理.
III. 配置Realserver脚本
在 4 台 Realserver 主机上建立如下脚本,然后执行
#!/bin/bash??
VIP=192.168.2.100??
/etc/rc.d/init.d/functions??
case “$1″ in??
start)??
?????????? ifconfig lo:0 $VIP netmask 255.255.255.255 broadcast $VIP up??
?????????? /sbin/route add -host $VIP dev lo:0??
?????????? 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??
?????????? sysctl -p >/dev/null??
?????????? echo "RealServer Start OK"??
?????????? ;;??
stop)??
?????????? ifconfig lo:0 down??
?????????? route del $VIP 2>/dev/null??
?????????? 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 "RealServer Stoped"??
?????????? ;;??
*)??
?????????? echo "Usage: $0 {start|stop}"??
?????????? exit 1??
esac??
exit 0
IV. 配置keepalived实现负载均衡和和高可用性
1.在 LVS-DR-Master 主机上编辑 keepalived 的配置文件 : vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived??
??
global_defs {??
notification_email {??
//此处填写你的邮件地址 }??
notification_email_from your email!??
??
smtp_server smtp.**.com??
smtp_connect_timeout 30??
router_id LVS_DEVEL??
}??
vrrp_instance VI_1 {??
state MASTER??
interface eth0??
lvs_sync_daemon_inteface eth0 //如是同一个网卡,可省略??
virtual_router_id 77 //标识ID,请务必保证内网唯一性,和备机必须一致!??
priority 100 //权重需比备机高??
advert_int 2 //主备检测间隔??
authentication { //主备通信密码,必须一致??
auth_type PASS??
auth_pass 1111??
}??
virtual_ipaddress {??
192.168.2.100 VIP,多个请换行填写??
??
}??
}??
??
virtual_server 192.168.2.100 80 {??
delay_loop 6 //每隔6秒检测Realserver健康状况??
lb_algo wlc //wlc算法,其他算法请参考ipvsadm十大算法??
lb_kind DR // 采用DR模式,即直接路由,其他还有TUN和NAT两种模式。??
persistence_timeout 1800 //设置超时未半小时??
protocol TCP??
??
real_server 192.168.2.101 80 { //第一个realserver,请注意80和后面{之间有个空格!??
weight 100 //权重??
HTTP_GET { //通过检测网页来检查Realserver健康状态??
url {??
path /XX/index.jsp //Realserver上的网页,如/model/index.jsp??
status_code 200 //正确的返回值,一般是200??
}??
connect_timeout 3 //超时3秒,则失败??
nb_get_retry 3 //失败重试次数??
delay_before_retry 3 //重试间隔时间??
}??
}??
??
real_server 192.168.2.102 80 {??
weight 100??
TCP_CHECK { //此范例为TCP检查方法,区别于HTTP方法,推荐使用HTTP方法。??
connect_timeout 10??
nb_get_retry 3??
delay_before_retry 3??
connect_port 80??
}??
}??
}??
??
real_server 192.168.2.103 80 {??
weight 100??
HTTP_GET {??
url {??
path /XX/index.jsp??
status_code 200??
}??
connect_timeout 3??
nb_get_retry 3??
delay_before_retry 3??
}??
}??
??
real_server 192.168.2.104 80 {??
weight 100??
HTTP_GET {??
url {??
path /XX/index.jsp??
status_code 200??
}??
connect_timeout 3??
nb_get_retry 3??
delay_before_retry 3??
}??
}
2.编辑 LVS-DR-Backup 上的 keepalived 配置文件(可拷贝 Master 上的),然后如下修改:
state BACKUP //主机上则为Master??
priority 90 //权值小于主机
其余保持不变即可。
V. 启动LVS
Realserver 脚本启动之后不需要操作,然后依次启动 LVS 主机上的 keepalived 服务即可: service keepalived start
二、LVS+Keepalived负载均衡双主互备架构
IP 信息清单: 名称 IP
双主互备方案需要 2 个 VIP,分别绑定到两台 LVS 主机上,然后修改 keepalived.conf 让两台 LVS 互相作为备机,代码稍作修改即可:
! Configuration File for keepalived??
??
global_defs {??
notification_email {??
//此处填写你的邮件地址 }??
notification_email_from your email!??
??
smtp_server smtp.**.com??
smtp_connect_timeout 30??
router_id LVS_DEVEL??
}??
vrrp_instance VI_1 {??
state MASTER??
interface eth0??
lvs_sync_daemon_inteface eth0 //如是同一个网卡,可省略??
virtual_router_id 77 //标识ID,请务必保证内网唯一性,和备机必须一致!??
priority 100 //权重需比备机高??
advert_int 2 //主备检测间隔??
authentication { //主备通信密码,必须一致??
auth_type PASS??
auth_pass 1111??
}??
virtual_ipaddress {??
192.168.2.100 VIP,多个请换行填写??
??
}??
}??
??
virtual_server 192.168.2.100 80 {??
delay_loop 6 //每隔6秒检测Realserver健康状况??
lb_algo wlc //wlc算法,其他算法请参考ipvsadm十大算法??
lb_kind DR // 采用DR模式,即直接路由,其他还有TUN和NAT两种模式。??
persistence_timeout 1800 //设置超时未半小时??
protocol TCP??
??
real_server 192.168.2.101 80 { //第一个realserver,请注意80和后面{之间有个空格!??
weight 100 //权重??
HTTP_GET { //通过检测网页来检查Realserver健康状态??
url {??
path /XX/index.jsp //Realserver上的网页,如/model/index.jsp??
status_code 200 //正确的返回值,一般是200??
}??
connect_timeout 3 //超时3秒,则失败??
nb_get_retry 3 //失败重试次数??
delay_before_retry 3 //重试间隔时间??
}??
}??
??
real_server 192.168.2.102 80 {??
weight 100??
TCP_CHECK { //此范例为TCP检查方法,区别于HTTP方法,推荐使用HTTP方法。??
connect_timeout 10??
nb_get_retry 3??
delay_before_retry 3??
connect_port 80??
}??
}??
}??
??
real_server 192.168.2.103 80 {??
weight 100??
HTTP_GET {??
url {??
path /XX/index.jsp??
status_code 200??
}??
connect_timeout 3??
nb_get_retry 3??
delay_before_retry 3??
}??
}??
??
real_server 192.168.2.104 80 {??
weight 100??
HTTP_GET {??
url {??
path /XX/index.jsp??
status_code 200??
}??
connect_timeout 3??
nb_get_retry 3??
delay_before_retry 3??
}??
}??
??
vrrp_instance VI_2 {??
state BACKUP??
interface eth0??
lvs_sync_daemon_inteface eth0 //如是同一个网卡,可省略??
virtual_router_id 78 //标识ID,请务必保证内网唯一性,和备机必须一致!??
priority 90 //权重需比备机高??
advert_int 2 //主备检测间隔??
authentication { //主备通信密码,必须一致??
auth_type PASS??
auth_pass 1111??
}??
virtual_ipaddress {??
192.168.2.105 VIP,多个请换行填写??
??
}??
}??
??
virtual_server 192.168.2.105 80 {??
delay_loop 6 //每隔6秒检测Realserver健康状况??
lb_algo wlc //wlc算法,其他算法请参考ipvsadm十大算法??
lb_kind DR // 采用DR模式,即直接路由,其他还有TUN和NAT两种模式。??
persistence_timeout 1800 //设置超时未半小时??
protocol TCP??
??
real_server 192.168.2.101 80 { //第一个realserver,请注意80和后面{之间有个空格!??
weight 100 //权重??
HTTP_GET { //通过检测网页来检查Realserver健康状态??
url {??
path /XX/index.jsp //Realserver上的网页,如/model/index.jsp??
status_code 200 //正确的返回值,一般是200??
}??
connect_timeout 3 //超时3秒,则失败??
nb_get_retry 3 //失败重试次数??
delay_before_retry 3 //重试间隔时间??
}??
}??
??
real_server 192.168.2.102 80 {??
weight 100??
TCP_CHECK { //此范例为TCP检查方法,区别于HTTP方法,推荐使用HTTP方法。??
connect_timeout 10??
nb_get_retry 3??
delay_before_retry 3??
connect_port 80??
}??
}??
}??
??
real_server 192.168.2.103 80 {??
weight 100??
HTTP_GET {??
url {??
path /XX/index.jsp??
status_code 200??
}??
connect_timeout 3??
nb_get_retry 3??
delay_before_retry 3??
}??
}??
??
real_server 192.168.2.104 80 {??
weight 100??
HTTP_GET {??
url {??
path /XX/index.jsp??
status_code 200??
}??
connect_timeout 3??
nb_get_retry 3??
delay_before_retry 3??
}??
}
说明:以上则为一台 LVS 主机的 keepalived 配置,由于篇幅过长,就不另提供相应的互备配置了,其实很简单,就是一边为 MARSTER 时,对应的互备配置就是 BACKUP,然后其他对应位置均做修改即可,通过 2 个 VIP 让 2 台 LVS 主机均处于工作状态,互为主备结构,提高资源利用率!
最佳建议:将域名同时绑定到 2 个 VIP,然后轮询解析,实现均衡流量的目的!
由于篇幅过长,有的地方可能没写到位,若涧客们有任何疑问请留言~