一桦卒、案例1：根據(jù)用戶的客戶端轉(zhuǎn)發(fā)請求

1.1 環(huán)境準(zhǔn)備

1.2 創(chuàng)建環(huán)境

\\web01
echo this is PC website>/app/www/lidao.html

\\web02
echo this is Mobile website>/app/www/lidao.html

1.3 lb01命令行測試

[root@lb01 ~]# curl 10.0.0.[7-8]/lidao.html

[1/2]: 10.0.0.7/lidao.html --> <stdout>
--_curl_--10.0.0.7/lidao.html
this is PC website

[2/2]: 10.0.0.8/lidao.html --> <stdout>
--_curl_--10.0.0.8/lidao.html
this is Mobile website
[root@lb01 ~]# 

1.4 在lb01判斷客戶端類型，

[root@lb01 /etc/nginx]# cat nginx.conf
……
    upstream default_pools{
        server 10.0.0.7:80 weight=1 max_fails=1 fail_timeout=10s;
    }
    upstream mobile_pools{
        server 10.0.0.8:80 weight=1 max_fails=1 fail_timeout=10s;
    }
    server{ 
        listen 80;
        server_name www.oldboy.com;
        location / {
            if ($http_user_agent ~* "Android|IOS") { 
                proxy_pass http://mobile_pools;
            }
        proxy_pass http://default_pools;
        proxy_set_header Host $host;
        proxy_set_header X_Forwarded-For $remote_addr;
        }
    }
……
[root@lb01 /etc/nginx]# nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
[root@lb01 /etc/nginx]# systemctl reload nginx

1>在命令行進(jìn)行測試

[root@lb01 /etc/nginx]# curl 10.0.0.5/lidao.html
this is PC website
[root@lb01 /etc/nginx]# curl -A ios 10.0.0.5/lidao.html
this is Mobile website
[root@lb01 /etc/nginx]# 

2>在火狐瀏覽器進(jìn)行
首先匿又，下載安裝firefox方灾，安裝 user agent switch 插件

其次，打開火狐瀏覽器進(jìn)行測試

二琳省、案例2：動靜態(tài)分離

根據(jù)用戶的uri進(jìn)行轉(zhuǎn)發(fā)location

技術(shù)大牛-李導(dǎo)

2.1 環(huán)境準(zhǔn)備

2.2 創(chuàng)建環(huán)境

\\\\web01 
[root@web01 ~]# mkdir -p  /app/www/upload/
[root@web01 ~]# echo  this is upload  >/app/www/upload/guoav.html
[root@web01 ~]# 

\\\\web02  
[root@web02 ~]# mkdir -p  /app/www/static/
[root@web02 ~]# echo  this is static  >/app/www/static/guoav.html 
[root@web02 ~]# 

\\\\web03  
[root@web03 ~]# mkdir -p  /app/www/
[root@web03 ~]# echo  this is default  >/app/www/guoav.html 
[root@web03 ~]#

檢查模擬環(huán)境是否ok

[root@web01 ~]# curl 10.0.0.7/upload/guoav.html
this is upload
[root@web01 ~]# curl 10.0.0.8/static/guoav.html
this is static
[root@web01 ~]# curl 10.0.0.9/guoav.html
this is default
[root@web01 ~]# 

2.3 配置lb01

[root@lb01 /etc/nginx]# cat nginx.conf
…… 
    upstream upload{
        server 10.0.0.7:80 weight=1 max_fails=1 fail_timeout=10s;
    }
    upstream static{
        server 10.0.0.8:80 weight=1 max_fails=1 fail_timeout=10s;
    }
    upstream default{
        server 10.0.0.9:80 weight=1 max_fails=1 fail_timeout=10s;
    }
    server{ 
        listen 80;
        server_name www.oldboy.com;
        location /upload {
            proxy_pass http://upload;
        proxy_set_header Host $host;
        proxy_set_header X_Forwarded-For $remote_addr;
        }
        location /static {
            proxy_pass http://static;
        proxy_set_header Host $host;
        proxy_set_header X_Forwarded-For $remote_addr;
        }
        location / {
            proxy_pass http://default;
        proxy_set_header Host $host;
        proxy_set_header X_Forwarded-For $remote_addr;
        }
    }
……
[root@lb01 /etc/nginx]# 
[root@lb01 /etc/nginx]# nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
[root@lb01 /etc/nginx]# systemctl reload nginx 

2.4 瀏覽器測試

根據(jù)用戶請求文件類型進(jìn)行轉(zhuǎn)發(fā)

三迎吵、負(fù)載均衡的排查思路

四、負(fù)載均衡的輪詢算法

默認(rèn)輪詢（rr）
加權(quán)輪詢（wrr）：weight
最小連接數(shù)（least conn）：根據(jù)后端服務(wù)器連接數(shù)分配任務(wù)
ip_hash：只要客戶端ip地址相同就會被轉(zhuǎn)發(fā)到同一臺機(jī)器上※※

五针贬、會話保持

cookie和session

1>cookie和session共同點(diǎn)：

存放用戶修改
key value類型击费，變量和變量內(nèi)容

2>cookie和session區(qū)別：

cookie：
存放在瀏覽器里面
存放簡單的信息或存放鑰匙
開發(fā)設(shè)置的
相應(yīng)的時(shí)候服務(wù)器給你設(shè)置

session：
存放在服務(wù)器中--redis中
存放敏感信息
鎖頭

六、高可用keepalived

Keepalived服務(wù)的工作原理※※※

1> Keepalived高可用對之間是通過VRRP進(jìn)行通信的桦他，VRRP是通過競選機(jī)制來確定主備的蔫巩，主的優(yōu)先高于備，因此快压，工作時(shí)主會優(yōu)先獲得所有的資源圆仔，備節(jié)點(diǎn)處于等待狀態(tài)，當(dāng)主掛了的時(shí)候蔫劣，備節(jié)點(diǎn)就會接管主節(jié)點(diǎn)的資源坪郭，然后頂替主節(jié)點(diǎn)對外提供服務(wù)。
2> 在Keepalived服務(wù)隊(duì)之間脉幢，只有作為主的服務(wù)器會一直發(fā)送VRRP廣播包歪沃，告訴備他還活著，此時(shí)備不會搶占主嫌松，當(dāng)主不可用時(shí)沪曙，即備監(jiān)聽不到主發(fā)送的廣播包時(shí)，就回啟動相關(guān)服務(wù)接管資源萎羔，保證業(yè)務(wù)的連續(xù)性液走。
3> 接管速度最快可以小于1秒。

6.1 環(huán)境準(zhǔn)備

1>每臺機(jī)器安裝好nginx
2>在lb01和lb02安裝keepalived----yum install -y keepalived
3>啟動服務(wù)贾陷，并設(shè)置開機(jī)自啟動
??啟動服務(wù)：systemctl start keepalived
??開機(jī)自啟動：systemctl enable keepalived
4>檢查服務(wù)：rpm -qa keepalived

6.2 配置文件

分為三個部分：
    GLOBAL CONFIGURATION：全局定義部分
    VRRPD CONFIGURATION：vrrp實(shí)例（rsync模塊）
    LVS CONFIGURATION：通過keepalived配置文件控制lvs

6.3 keepalived配置文件詳解

https://www.processon.com/view/link/5d034b4ee4b08ceab31b8e11

6.4 配置keepalived

對lb01(主)和lb02(備)進(jìn)行以下配置
注：配置時(shí)請注意lbo1主負(fù)載均衡與lb02備負(fù)載均衡有些不同

[root@lb01 /etc/keepalived]# cp keepalived.conf{,.bak}
[root@lb01 /etc/keepalived]# ll
total 8
-rw-r--r-- 1 root root 3598 Jan  6 16:47 keepalived.conf
-rw-r--r-- 1 root root 3598 Jun 14 15:56 keepalived.conf.bak
[root@lb01 /etc/keepalived]# cat keepalived.conf
! Configuration File for keepalived

global_defs {
    router_id lb01
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
     10.0.0.3/24 dev eth0 label eth0:1  
    }
}
[root@lb01 /etc/keepalived]# systemctl restart keepalived.service

6.5 命令行測試

6.7 抓包測試