nginx一般可以用于七層的負(fù)載均衡，這篇文章將介紹一些負(fù)載均衡的基本知識(shí)以及使用nginx進(jìn)行負(fù)載均衡的簡(jiǎn)單的例子。
四層負(fù)載均衡 vs 七層負(fù)載均衡
經(jīng)常會(huì)說(shuō)七層負(fù)載均衡還是四層負(fù)載均衡，其實(shí)根據(jù)ISO的OSI網(wǎng)絡(luò)模型的所在層的叫法而決定的，nginx因?yàn)樵谑褂胔ttp協(xié)議在應(yīng)用層進(jìn)行負(fù)載均衡的操作，所以被稱為七層負(fù)載均衡。而諸如LVS在TCP層進(jìn)行負(fù)載均衡操作的則被稱為四層負(fù)載均衡。一般來(lái)說(shuō)，有如下層的負(fù)載均衡分類：
常見(jiàn)軟件的支持
常見(jiàn)的負(fù)載均衡算法
負(fù)載均衡常見(jiàn)有如下幾種算法：
負(fù)載均衡演示實(shí)例：普通輪詢
接下來(lái)使用nginx來(lái)演示一下如何進(jìn)行普通輪詢：
事前準(zhǔn)備
事前在7001/7002兩個(gè)端口分別啟動(dòng)兩個(gè)服務(wù)，用于顯示不同信息，為了演示方便，使用tornado做了一個(gè)鏡像，通過(guò)docker容器啟動(dòng)時(shí)傳遞的參數(shù)不同用于顯示服務(wù)的不同。
[root@kong ~]# docker run -d -p 7001:8080 liumiaocn/tornado:latest python /usr/local/bin/daemon.py "User Service 1: 7001"
ddba0abd24524d270a782c3fab907f6a35c0ce514eec3159357bded09022ee57
[root@kong ~]# docker run -d -p 7002:8080 liumiaocn/tornado:latest python /usr/local/bin/daemon.py "User Service 1: 7002"
95deadd795e19f675891bfcd44e5ea622c95615a95655d1fd346351eca707951
[root@kong ~]#
[root@kong ~]# curl http://192.168.163.117:7001
Hello, Service :User Service 1: 7001
[root@kong ~]#
[root@kong ~]# curl http://192.168.163.117:7002
Hello, Service :User Service 1: 7002
[root@kong ~]#
啟動(dòng)nginx
[root@kong ~]# docker run -p 9080:80 --name nginx-lb -d nginx
9d53c7e9a45ef93e7848eb3f4e51c2652a49681e83bda6337c89a3cf2f379c74
[root@kong ~]# docker ps |grep nginx-lb
9d53c7e9a45e nginx "nginx -g 'daemon ..." 11 seconds ago Up 10 seconds 0.0.0.0:9080->80/tcp nginx-lb
[root@kong ~]#
nginx代碼段
準(zhǔn)備如下nginx代碼段將其添加到nginx的/etc/nginx/conf.d/default.conf中
http {
upstream nginx_lb {
server 192.168.163.117:7001;
server 192.168.163.117:7002;
}
server {
listen 80;
server_name www.liumiao.cn 192.168.163.117;
location / {
proxy_pass http://nginx_lb;
}
}
修改default.conf的方法
可以通過(guò)在容器中安裝vim達(dá)到效果，也可以在本地修改然后通過(guò)docker cp傳入，或者直接sed修改都可。如果在容器中安裝vim，使用如下方式即可
[root@kong ~]# docker exec -it nginx-lb sh
# apt-get update
...省略
# apt-get install vim
...省略
修改前
# cat default.conf
server {
listen 80;
server_name localhost;
#charset koi8-r;
#access_log /var/log/nginx/host.access.log main;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
}
#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/html;
}
# proxy the PHP scripts to Apache listening on 127.0.0.1:80
#
#location ~ \.php$ {
# proxy_pass http://127.0.0.1;
#}
# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
#location ~ \.php$ {
# root html;
# fastcgi_pass 127.0.0.1:9000;
# fastcgi_index index.php;
# fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;
# include fastcgi_params;
#}
# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
#location ~ /\.ht {
# deny all;
#}
}
#
修改后
# cat default.conf
upstream nginx_lb {
server 192.168.163.117:7001;
server 192.168.163.117:7002;
}
server {
listen 80;
server_name www.liumiao.cn 192.168.163.117;
#charset koi8-r;
#access_log /var/log/nginx/host.access.log main;
location / {
#root /usr/share/nginx/html;
#index index.html index.htm;
proxy_pass http://nginx_lb;
}
#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/html;
}
# proxy the PHP scripts to Apache listening on 127.0.0.1:80
#
#location ~ \.php$ {
# proxy_pass http://127.0.0.1;
#}
# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
#location ~ \.php$ {
# root html;
# fastcgi_pass 127.0.0.1:9000;
# fastcgi_index index.php;
# fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;
# include fastcgi_params;
#}
# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
#location ~ /\.ht {
# deny all;
#}
}
#
重啟nginx容器
[root@kong ~]# docker restart nginx-lb
nginx-lb
[root@kong ~]#
確認(rèn)結(jié)果
可以清晰地看到按照順序，進(jìn)行輪詢：
[root@kong ~]# curl http://localhost:9080
Hello, Service :User Service 1: 7001
[root@kong ~]# curl http://localhost:9080
Hello, Service :User Service 1: 7002
[root@kong ~]# curl http://localhost:9080
Hello, Service :User Service 1: 7001
[root@kong ~]# curl http://localhost:9080
Hello, Service :User Service 1: 7002
[root@kong ~]#
負(fù)載均衡演示實(shí)例：權(quán)重輪詢
而在此基礎(chǔ)上，進(jìn)行權(quán)重輪詢只需要加上weight即可
修改default.conf
按照如下修改default.conf
# cp default.conf default.conf.org
# vi default.conf
# diff default.conf default.conf.org
2,3c2,3
< server 192.168.163.117:7001 weight=100;
< server 192.168.163.117:7002 weight=200;
---
> server 192.168.163.117:7001;
> server 192.168.163.117:7002;
#
重啟nginx容器
[root@kong ~]# docker restart nginx-lb
nginx-lb
[root@kong ~]#
確認(rèn)結(jié)果
可以看到輪詢結(jié)果按照1/3和2/3的比重在進(jìn)行了：
[root@kong ~]# curl http://localhost:9080
Hello, Service :User Service 1: 7001
[root@kong ~]# curl http://localhost:9080
Hello, Service :User Service 1: 7002
[root@kong ~]# curl http://localhost:9080
Hello, Service :User Service 1: 7002
[root@kong ~]#
總結(jié)
以上就是這篇文章的全部?jī)?nèi)容了，希望本文的內(nèi)容對(duì)大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值，謝謝大家對(duì)腳本之家的支持。如果你想了解更多相關(guān)內(nèi)容請(qǐng)查看下面相關(guān)鏈接
