目录
Haproxy概述
haproxy---主要是做负载均衡的7层，也可以做4层负载均衡
apache也可以做7层负载均衡，但是很麻烦。实际工作中没有人用。
负载均衡是通过OSI协议对应的
7层负载均衡：用的7层http协议，
4层负载均衡：用的是tcp协议加端口号做的负载均衡
haproxy算法：
1.roundrobin
基于权重进行轮询,在服务器的处理时间保持均匀分布时,这是最平衡,最公平的算法.此算法是动态的,这表示其权重可以在运行时进行调整.不过在设计上,每个后端服务器仅能最多接受4128个连接
2.static-rr基于权重进行轮询,与roundrobin类似,但是为静态方法,在运行时调整其服务器权重不会生效.不过,其在后端服务器连接数上没有限制
3.leastconn新的连接请求被派发至具有最少连接数目的后端服务器.
Haproxy实现七层负载
keepalived+haproxy
192.168.134.165 master
192.168.134.166 slave
192.168.134.163 nginx-server
192.168.134.164 nginx-server
192.168.134.160 VIP（虚拟IP）
①部署nginx-server测试页面
两台nginx都部署方便测试
[root@server03 ~]# yum -y install nginx
[root@server03 ~]# systemctl start nginx
[root@server03 ~]# echo "webserver01..." > /usr/share/nginx/html/index.html
[root@server04 ~]# yum -y install nginx
[root@server04 ~]# systemctl start nginx
[root@server04 ~]# echo "webserver02..." > /usr/share/nginx/html/index.html
②(主/备)部署负载均衡器
[root@server01 ~]# yum -y install haproxy
[root@server01 ~]# vim /etc/haproxy/haproxy.cfg
global
log 127.0.0.1 local2 info
pidfile /var/run/haproxy.pid
maxconn 4000
user haproxy
group haproxy
daemon
nbproc 1
defaults
mode http
log global
retries 3
option redispatch
maxconn 4000
contimeout 5000
clitimeout 50000
srvtimeout 50000
listen stats
bind *:81
stats enable
stats uri /haproxy
stats auth aren:123
frontend web
mode http
bind *:80
option httplog
acl html url_reg -i \.html$
use_backend httpservers if html
default_backend httpservers
backend httpservers
balance roundrobin
server http1 192.168.134.163:80 maxconn 2000 weight 1 check inter 1s rise 2 fall 2
server http2 192.168.134.164:80 maxconn 2000 weight 1 check inter 1s rise 2 fall 2
[root@server01 ~]# systemctl start haproxy
浏览器访问haproxy监控
master:
slave:
页面主要参数解释
Queue
Cur: current queued requests //当前的队列请求数量
Max：max queued requests //最大的队列请求数量
Limit： //队列限制数量
Errors
Req：request errors //错误请求
Conn：connection errors //错误的连接
Server列表：
Status:状态，包括up(后端机活动)和down(后端机挂掉)两种状态
LastChk: 持续检查后端服务器的时间
Wght: (weight) : 权重
③部署keepalived高可用
注意：master和slave的优先级不一样，但虚拟路由id(virtual_router_id)保持一致；并且slave配置 nopreempt（不抢占资源）
master：
[root@server01 ~]# yum -y install keepalived
[root@server01 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
router_id director1
}
vrrp_instance VI_1 {
state MASTER
interface ens33
virtual_router_id 80
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.134.160/24
}
}
[root@server01 ~]# systemctl start keepalived
slaver：
[root@localhost ~]# yum -y install keepalived
[root@localhost ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
router_id directory2
}
vrrp_instance VI_1 {
state BACKUP
interface ens33
nopreempt
virtual_router_id 80
priority 50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.134.160/24
}
}
[root@localhost ~]# systemctl start keepalived
查看IP
④增加对haproxy健康检查
两台机器都做，让Keepalived以一定时间间隔执行一个外部脚本，脚本的功能是当Haproxy失败，则关闭本机的Keepalived。
[root@server01 ~]# vim /etc/keepalived/check.sh
#!/bin/bash
/usr/bin/curl -I http://localhost &>/dev/null
if [ $? -ne 0 ];then
# /etc/init.d/keepalived stop
systemctl stop keepalived
fi
[root@server01 ~]# chmod a+x /etc/keepalived/check.sh
在keepalived增加健康检查配置vrrp_script check_haproxy并且用 track_script调用。
! Configuration File for keepalived
global_defs {
router_id director1
}
vrrp_script check_haproxy {
script "/etc/keepalived/check.sh"
interval 5
}
vrrp_instance VI_1 {
state MASTER
interface ens33
virtual_router_id 80
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.134.160/24
}
track_script {
check_haproxy
}
}
重启keepalived
[root@server01 ~]# systemctl restart keepalived
⑤测试
关闭master的haproxy服务可以发现master的keepalived服务也关闭，此时master上的VIP转移到slave上
- 关闭master的服务并查看VIP
- 查看slave的IP可以发现VIP跳转至此。
- 在web界面查看服务是否正常
第一次刷新
第二次刷新
