Haproxy 基礎
軟件：haproxy---主要是做負載均衡的7層，也可以做4層負載均衡
apache也可以做7層負載均衡，但是很麻煩。實際工作中沒有人用。
負載均衡是通過OSI協議對應的
7層負載均衡：用的7層http協議，
4層負載均衡：用的是tcp協議加端口號做的負載均衡
-----------------------------------------------------------------------------------------
ha-proxy概述
ha-proxy是一款高性能的負載均衡軟件。因爲其專注於負載均衡這一些事情，因此與nginx比起來在負載均衡這件事情上做更好，更專業。
ha-proxy的特點
ha-proxy 作爲目前流行的負載均衡軟件，必須有其出色的一面。下面介紹一下ha-proxy相對LVS，Nginx等負載均衡軟件的優點。
•支持tcp / http 兩種協議層的負載均衡，使得其負載均衡功能非常豐富。
•支持8種左右的負載均衡算法，尤其是在http模式時，有許多非常實在的負載均衡算法，適用各種需求。
•性能非常優秀，基於單進程處理模式（和Nginx類似）讓其性能卓越。
•擁有一個功能出色的監控頁面，實時瞭解系統的當前狀況。
•功能強大的ACL支持，給用戶極大的方便。
haproxy算法：
1.roundrobin
基於權重進行輪詢,在服務器的處理時間保持均勻分佈時,這是最平衡,最公平的算法.此算法是動態的,這表示其權重可以在運行時進行調整.
2.static-rr
基於權重進行輪詢,與roundrobin類似,但是爲靜態方法,在運行時調整其服務器權重不會生效.不過,其在後端服務器連接數上沒有限制
3.leastconn
新的連接請求被派發至具有最少連接數目的後端服務器.
1、Haproxy 實現七層負載
Keepalived + Haproxy
=================================================================================
/etc/haproxy/haproxy.cfg
global //關於進程的全局參數
log 127.0.0.1 local2 info #日誌服務器
pidfile /var/run/haproxy.pid #pid文件
maxconn 4000 #最大連接數
user haproxy #用戶
group haproxy #組
daemon #守護進程方式後臺運行
nbproc 1 #工作進程數量 cpu內核是幾就寫幾
defaults 段用於爲其它配置段提供默認參數
listen是frontend和backend的結合體
frontend 虛擬服務VIrtual Server
backend 真實服務器Real Server
調度器可以同時爲多個站點調度，如果使用frontend、backend的方式：
frontend1 backend1
frontend2 backend2
frontend3 backend3
Keepalived + Haproxy
=================================================================================
拓撲結構
[vip: 192.168.246.17]
[LB1 Haproxy] [LB2 Haproxy]
192.168.246.169 192.168.246.161
[httpd] [httpd]
192.168.246.162 192.168.246.163
一、Haproxy實施步驟
1. 準備工作（集羣中所有主機）
[root@ha-proxy-master ~]# cat /etc/hosts
127.0.0.1 localhost
192.168.246.169 ha-proxy-master
192.168.246.161 ha-proxy-slave
192.168.246.162 test-nginx1
192.168.246.163 test-nginx2
2. RS配置
配置好網站服務器，測試所有RS,所有機器安裝nginx
[root@test-nginx1 ~]# yum install -y nginx
[root@test-nginx1 ~]# systemctl start nginx
[root@test-nginx1 ~]# echo "test-nginx1" >> /usr/share/nginx/html/index.html
# 所有nginx服務器按順序輸入編號，方便區分。
3. 調度器配置Haproxy（主/備）都執行
[root@ha-proxy-master ~]# yum -y install haproxy
[root@ha-proxy-master ~]# cp -rf /etc/haproxy/haproxy.cfg{,.bak}
[root@ha-proxy-master ~]# sed -i -r '/^[ ]*#/d;/^$/d' /etc/haproxy/haproxy.cfg
[root@ha-proxy-master ~]# vim /etc/haproxy/haproxy.cfg
global
log 127.0.0.1 local2 info
pidfile /var/run/haproxy.pid
maxconn 4000 #優先級低
user haproxy
group haproxy
daemon #以後臺形式運行ha-proxy
nbproc 1 #工作進程數量 cpu內核是幾就寫幾
defaults
mode http #工作模式 http ,tcp 是 4 層,http是 7 層
log global
retries 3 #健康檢查。3次連接失敗就認爲服務器不可用，主要通過後面的check檢查
option redispatch #服務不可用後重定向到其他健康服務器。
maxconn 4000 #優先級中
contimeout 5000 #ha服務器與後端服務器連接超時時間，單位毫秒ms
clitimeout 50000 #客戶端超時
srvtimeout 50000 #後端服務器超時
listen stats
bind *:81
stats enable
stats uri /haproxy #使用瀏覽器訪問 http://192.168.246.169/haproxy,可以看到服務器狀態
stats auth qianfeng:123 #用戶認證，客戶端使用elinks瀏覽器的時候不生效
frontend web
mode http
bind *:80 #監聽哪個ip和什麼端口
option httplog #日誌類別 http 日誌格式
acl html url_reg -i \.html$ #1.訪問控制列表名稱html。規則要求訪問以html結尾的url(可選)
use_backend httpservers if html #2.如果滿足acl html規則，則推送給後端服務器httpservers
default_backend httpservers #默認使用的服務器組
backend httpservers #名字要與上面的名字必須一樣
balance roundrobin #負載均衡的方式
server http1 192.168.246.162:80 maxconn 2000 weight 1 check inter 1s rise 2 fall 2
server http2 192.168.246.163:80 maxconn 2000 weight 1 check inter 1s rise 2 fall 2
將配置文件拷貝到slave服務器
[root@ha-proxy-master ~]# scp /etc/haproxy/haproxy.cfg 192.168.246.161:/etc/haproxy/
兩臺機器啓動設置開機啓動
[root@ha-proxy-master ~]# systemctl start haproxy
[root@ha-proxy-master ~]# systemctl enable haproxy
4.測試主/備(瀏覽器訪問)
主：192.168.246.169：81/haproxy
備：192.168.246.161：81/haproxy
頁面主要參數解釋
Queue
Cur: current queued requests //當前的隊列請求數量
Max：max queued requests //最大的隊列請求數量
Limit： //隊列限制數量
Errors
Req：request errors //錯誤請求
Conn：connection errors //錯誤的連接
Server列表：
Status:狀態，包括up(後端機活動)和down(後端機掛掉)兩種狀態
LastChk: 持續檢查後端服務器的時間
Wght: (weight) : 權重
========================================================
2.測試訪問
通過訪問haparoxy的ip地址訪問到後端服務器
# curl http://192.168.246.169
如果出現bind失敗的報錯，執行下列命令
setsebool -P haproxy_connect_any=1
二、Keepalived實現調度器HA
注：主/備調度器均能夠實現正常調度
1. 主/備調度器安裝軟件
[root@ha-proxy-master ~]# yum install -y keepalived
[root@ha-proxy-slave ~]# yum install -y keepalived
[root@ha-proxy-master ~]# mv /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak嗎v
[root@ha-proxy-master ~]# 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 {
192.168.246.17/24
}
}
[root@ha-proxy-slave ~]# mv /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
[root@ha-proxy-slave ~]# 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 {
192.168.246.17/24
}
}
3. 啓動KeepAlived（主備均啓動）
[root@ha-proxy-master ~]# systemctl start keepalived
[root@ha-proxy-master ~]# systemctl enable keepalived
[root@ha-proxy-master ~]# ip a
4. 擴展對調度器Haproxy健康檢查（可選）
思路：兩臺機器都做
讓Keepalived以一定時間間隔執行一個外部腳本，腳本的功能是當Haproxy失敗，則關閉本機的Keepalived
a. script
[root@ha-proxy-master ~]# cat /etc/keepalived/check_haproxy_status.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@ha-proxy-master ~]# chmod a+x /etc/keepalived/check_haproxy_status.sh
b. keepalived使用script
[root@ha-proxy-master keepalived]# vim keepalived.conf
! Configuration File for keepalived
global_defs {
router_id director1
}
vrrp_script check_haproxy {
script "/etc/keepalived/check_haproxy_status.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 {
192.168.246.17/24
}
track_script {
check_haproxy
}
}
[root@ha-proxy-slave keepalived]# vim keepalived.conf
! Configuration File for keepalived
global_defs {
router_id directory2
}
vrrp_script check_haproxy {
script "/etc/keepalived/check_haproxy_status.sh"
interval 5
}
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 {
192.168.246.17/24
}
track_script {
check_haproxy
}
}
[root@ha-proxy-master keepalived]# systemctl restart keepalived
[root@ha-proxy-slave keepalived]# systemctl restart keepalived
注：必須先啓動haproxy，再啓動keepalived
兩臺機器都配置haproxy的日誌:需要打開註釋並添加
[root@ha-proxy-master ~]# vim /etc/rsyslog.conf
# Provides UDP syslog reception #由於haproxy的日誌是用udp傳輸的,所以要啓用rsyslog的udp監聽
$ModLoad imudp
$UDPServerRun 514
找到 #### RULES #### 下面添加
local2.* /var/log/haproxy.log
[root@ha-proxy-master ~]# systemctl restart rsyslog
[root@ha-proxy-master ~]# systemctl restart haproxy
[root@ha-proxy-master ~]# tail -f /var/log/haproxy.log
2019-07-13T23:11:35+08:00 localhost haproxy[906]: Connect from 192.168.246.1:56866 to 192.168.246.17:80 (web/HTTP)
2019-07-13T23:11:35+08:00 localhost haproxy[906]: Connect from 192.168.246.1:56867 to 192.168.246.17:80 (web/HTTP)
2019-07-13T23:13:39+08:00 localhost haproxy[906]: Connect from 192.168.246.1:56889 to 192.168.246.17:80 (stats/HTTP)
2019-07-13T23:13:39+08:00 localhost haproxy[906]: Connect from 192.168.246.1:56890 to 192.168.246.17:80 (web/HTTP)
2019-07-13T23:14:07+08:00 localhost haproxy[906]: Connect from 192.168.246.1:56895 to 192.168.246.17:80 (web/HTTP)
2019-07-13T23:14:07+08:00 localhost haproxy[906]: Connect from 192.168.246.1:56896 to 192.168.246.17:80 (stats/HTTP)
作業：Haproxy 實現四層負載
兩臺haproxy配置文件:
[root@ha-proxy-master ~]# cat /etc/haproxy/haproxy.cfg
Haproxy L4
=================================================================================
global
log 127.0.0.1 local2
pidfile /var/run/haproxy.pid
maxconn 4000
user haproxy
group haproxy
daemon
nbproc 1
defaults
mode http
log global
option redispatch
retries 3
maxconn 4000
contimeout 5000
clitimeout 50000
srvtimeout 50000
listen stats
bind *:81
stats enable
stats uri /haproxy
stats auth qianfeng:123
frontend web
mode http
bind *:80
option httplog
default_backend httpservers
backend httpservers
balance roundrobin
server http1 192.168.246.162:80 maxconn 2000 weight 1 check inter 1s rise 2 fall 2
server http2 192.168.246.163:80 maxconn 2000 weight 1 check inter 1s rise 2 fall 2
listen mysql
bind *:3306
mode tcp
balance roundrobin
server mysql1 192.168.246.163:3306 weight 1 check inter 1s rise 2 fall 2
server mysql2 192.168.246.162:3306 weight 1 check inter 1s rise 2 fall 2
inter表示健康檢查的間隔，單位爲毫秒 可以用1s等，fall代表健康檢查失敗2回後放棄檢查。rise代表連續健康檢查成功2此後將認爲服務器可用。默認的，haproxy認爲服務時永遠可用的，除非加上check讓haproxy確認服務是否真的可用。
找一臺機器做爲客戶端去測試，在測試的時候注意mysql的遠程登錄權限