lvs+keepalived高可用负载均衡集群双主实现
项目说明1、 使用LVS负载均衡用户请求到后端web服务器，并且实现健康状态检查
2、 使用keepalived高可用LVS，避免LVS单点故障
3、 集群中分别在LK-01和LK-02运行一个VIP地址，实现LVS双主
4、 用户通过DNS轮训的方式实现访问集群的负载均衡（不演示）
环境拓扑
http://s3.运维网.com/wyfs02/M00/6E/B0/wKioL1WDAOCy986aAAIliC4Cy7k170.jpg
环境介绍
IP地址
功能描述
LK-01
172.16.4.100
调度用户请求到后端web服务器，并且和LK-02互为备份
LK-02
172.16.4.101
调度用户请求到后端web服务器，并且和LK-01互为备份
WEB-01
172.16.4.102
提供web服务
WEB-02
172.16.4.103
提供web服务
DNS
172.16.4.10
实现DNS轮训解析用户请求域名地址
VIP1
172.16.4.1
用户访问集群的入口地址，可能在LK-01，也可能在LK-02
VIP2
172.16.4.2
用户访问集群的入口地址，可能在LK-01，也可能在LK-02
环境配置
后端WEB服务器配置
Web服务器的配置极其简单，只需要提供测试页面启动web服务即可，配置如下：
Web-01配置
# echo "web-01" >/var/www/html/index.html
# service httpd start Web-02配置
# echo "web-02" >/var/www/html/index.html
# service httpd start LVS访问后端web服务器，验证web服务提供成功
# curl 172.16.4.102
web-01
# curl 172.16.4.103
web-02 出现设置的页面，就说明web服务是正常
WEB服务器使用脚本进行配置LVS-DR模式客户端环境
由于是双主模式，客户端需要启用两个子接口配置两个VIP地址。
#!/bin/bash
#
vip1=172.16.4.1
vip2=172.16.4.2
interface1="lo:0"
interface2="lo:1"
case $1 in
start)
echo 1> /proc/sys/net/ipv4/conf/all/arp_ignore
echo 1> /proc/sys/net/ipv4/conf/lo/arp_ignore
echo 2> /proc/sys/net/ipv4/conf/all/arp_announce
echo 2> /proc/sys/net/ipv4/conf/lo/arp_announce
ifconfig$interface1 $vip1 broadcast $vip1 netmask 255.255.255.255 up
ifconfig$interface2 $vip2 broadcast $vip2 netmask 255.255.255.255 up
route add-host $vip1 dev $interface1
route add-host $vip2 dev $interface2
;;
stop)
echo 0 >/proc/sys/net/ipv4/conf/all/arp_ignore
echo 0 >/proc/sys/net/ipv4/conf/lo/arp_ignore
echo 0 >/proc/sys/net/ipv4/conf/all/arp_announce
echo 0 >/proc/sys/net/ipv4/conf/lo/arp_announce
ifconfig$interface1 down
ifconfig$interface2 down
;;
status)
if ifconfiglo:0 |grep $vip1 &> /dev/null; then
echo"ipvs1 is running."
else
echo"ipvs1 is stopped."
fi
if ifconfiglo:1 |grep $vip2 &> /dev/null; then
echo"ipvs2 is running."
else
echo"ipvs2 is stopped."
fi
;;
*)
echo"Usage: `basename $0` {start|stop|status}"
exit 1
esacLVS+keepalived设置
Keepalived安装
Centos6.6已经收录了keepalived，直接使用yum安装即可
# yum -y install keepalived
# yum -y install keepalived HK-01节点配置
# vim /etc/keepalived/keepalived.conf
global_defs {
router_idLVS_DEVEL
}
vrrp_script chk_mt_down {
script"[[ -f /etc/keepalived/down ]] && exit 1 || exit 0" #定义一个脚本，判断down文件是否存在，存在就退出执行，不存在继续执行
interval 1 #1秒检测一次
weight -5 #如果down文件存在，VRRP实例优先级减5
}
vrrp_instance VI_1 { #定义VRRP热备实例
state MASTER #MASTER表示主节点
interfaceeth 0 #承载VIP的物理接口
virtual_router_id 51#虚拟路由器的ID号
priority 100 #优先级
advert_int 1 #通知间隔秒数（心跳频率）
authentication { #设置主备节点直接的认证信息
auth_type PASS#
auth_pass asdfgh #
}
virtual_ipaddress {#设置集群中的VIP地址
172.16.4.1/32 brd 172.16.4.1 dev eth0 label eth0:0
}
track_script {
chk_mt_down#调用上面定义的脚本，如果这里没有调用，那么上面定义的脚本是无法生效的
}
}
vrrp_instance VI_2 { #定义实例为HK-02的备份节点
state BACKUP
interfaceeth 0
virtual_router_id 52
priority 99 #设置优先级，低于主服务器
advert_int 1
authentication {
auth_type PASS
auth_pass qwerty
}
virtual_ipaddress {
172.16.4.2
}
track_script {
chk_mt_down
}
}
virtual_server 172.16.4.1 80 { #定义一个VIP地址和端口
delay_loop 6
lb_algo rr #轮训算法
lb_kind DR #调度类型
nat_mask 255.255.0.0
# persistence_timeout 50 #设置长连接时长，单位秒
protocolTCP
real_server 172.16.4.102 80 { #定义后端RS服务器的相关信息
weight 1 #设置权重
HTTP_GET { #设置健康状态检测方式
url { #健康检查判断后端服务器首页是否访问正常（返回200状态码），如果正常则认为服务器正常
path /index.html
status 200
}
connect_timeout 3 #连接超时
nb_get_retry 3 #重试次数
delay_before_retry 1 #重试时间间隔
}
}
real_server 172.16.4.103 80 {
weight 1
HTTP_GET {
url {
path /index.html
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 1
}
}
}
virtual_server 172.16.4.2 80 {
delay_loop 6
lb_algo rr
lb_kind DR
nat_mask 255.255.0.0
# persistence_timeout 50
protocol TCP
real_server 172.16.4.102 80 {
weight 1
HTTP_GET {
url {
path /index.html
status 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 1
}
}
real_server 172.16.4.103 80 {
weight 1
HTTP_GET {
url {
path /index.html
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 1
}
}
} LK-02节点设置
LK-02节点设置中的参数在LK-01节点都有注释
# vim /etc/keepalived/keepalived.conf
global_defs {
router_idLVS_DEVEL
}
vrrp_script chk_mt_down {
script"[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
interval 1
weight -5
}
vrrp_instance VI_1 {
state BACKUP
interfaceeth 0
virtual_router_id 51
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass asdfgh
}
virtual_ipaddress {
172.16.4.1/32 brd 172.16.4.1 dev eth0 label eth0:0
}
track_script {
chk_mt_down
}
}
vrrp_instance VI_2 {
state MASTER
interfaceeth 0
virtual_router_id 52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass qwerty
}
virtual_ipaddress {
172.16.4.2
}
track_script{
chk_mt_down
}
}
virtual_server 172.16.4.1 80 {
delay_loop 6
lb_algo rr
lb_kind DR
nat_mask 255.255.0.0
# persistence_timeout 50
protocol TCP
real_server 172.16.4.102 80 {
weight 1
HTTP_GET{
url {
path /index.html
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 1
}
}
real_server 172.16.4.103 80 {
weight 1
HTTP_GET{
url {
path /index.html
status 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 1
}
}
}
virtual_server 172.16.4.2 80 {
delay_loop 6
lb_algo rr
lb_kind DR
nat_mask 255.255.0.0
# persistence_timeout 50
protocol TCP
real_server 172.16.4.102 80 {
weight 1
HTTP_GET{
url {
path /index.html
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 1
}
}
real_server 172.16.4.103 80 {
weight 1
HTTP_GET{
url {
path /index.html
status 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 1
}
}
} 设置完成启动keepalived
# service keepalived start
# service keepalived start验证
Vip地址和集群规则验证
LK-01查看，VIP地址启动正常，而且ipvs命令自动设置成功
# ip addr show dev eth0
2: eth0: mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:22:c5:c2 brd ff:ff:ff:ff:ff:ff
inet172.16.4.100/16 brd 172.16.255.255 scope global eth0
inet172.16.4.1/32 brd 172.16.4.1 scope global eth0:0
inet6fe80::20c:29ff:fe22:c5c2/64 scope link
valid_lft forever preferred_lft forever
# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
->RemoteAddress:Port ForwardWeight ActiveConn InActConn
TCP 172.16.4.1:80 rr
->172.16.4.102:80 Route 1 0 0
->172.16.4.103:80 Route 1 0 0
TCP 172.16.4.2:80 rr
->172.16.4.102:80 Route 1 0 0
->172.16.4.103:80 Route 1 0 0 LK-02查看，VIP和ipvs策略都有
# ip addr show dev eth0
2: eth0: mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:f1:dd:b2 brd ff:ff:ff:ff:ff:ff
inet172.16.4.101/16 brd 172.16.255.255 scope global eth0
inet172.16.4.2/32 scope global eth0
inet6fe80::20c:29ff:fef1:ddb2/64 scope link
valid_lft forever preferred_lft forever
# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
->RemoteAddress:Port ForwardWeight ActiveConn InActConn
TCP 172.16.4.1:80 rr
->172.16.4.102:80 Route 1 0 0
->172.16.4.103:80 Route 1 0 0
TCP 172.16.4.2:80 rr
->172.16.4.102:80 Route 1 0 0
->172.16.4.103:80 Route 1 0 0负载均衡验证
无论访问vip1还是vip2都已经实现了负载均衡功能
# curl 172.16.4.1
web-02
# curl 172.16.4.1
web-01
# curl 172.16.4.1
web-02
# curl 172.16.4.1
web-01
# curl 172.16.4.2
web-02
# curl 172.16.4.2
web-01
# curl 172.16.4.2
web-02
# curl 172.16.4.2
web-01高可用验证
使用down文件关闭LK-02节点
# touch /etc/keepalived/down 查看LK-01节点的VIP地址，发现VIP1和VIP2都已经在LK-01节点启动了
# ip addr show dev eth0
2: eth0: mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:22:c5:c2 brd ff:ff:ff:ff:ff:ff
inet172.16.4.100/16 brd 172.16.255.255 scope global eth0
inet172.16.4.1/32 brd 172.16.4.1 scope global eth0:0
inet172.16.4.2/32 scope global eth0
inet6fe80::20c:29ff:fe22:c5c2/64 scope link
valid_lft forever preferred_lft forever 集群访问正常
# curl 172.16.4.1
web-02
# curl 172.16.4.1
web-01
# curl 172.16.4.2
web-02
# curl 172.16.4.2
web-01健康检测验证
手动关闭web-02节点
# service httpd stop 查看集群规则设置,已经自动移除了web-02节点
# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
->RemoteAddress:Port ForwardWeight ActiveConn InActConn
TCP 172.16.4.1:80 rr
->172.16.4.102:80 Route 1 0 1
TCP 172.16.4.2:80 rr
->172.16.4.102:80 Route 1 0 1
# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
->RemoteAddress:Port ForwardWeight ActiveConn InActConn
TCP 172.16.4.1:80 rr
->172.16.4.102:80 Route 1 0 0
TCP 172.16.4.2:80 rr
->172.16.4.102:80 Route 1 0 0
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