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Nginx加权轮询及upstream实战演练- ip_hash/weight/upstream

0.0.1 upstream

proxy_pass只能定义一个主机,而upstream则是定义一个主机组,之后proxy_pass调用这个组

示例:

upstream backend {
    server backend1.example.com       weight=5;
    server backend2.example.com:8080;
    server unix:/tmp/backend3;


    server backup1.example.com:8080   backup;
    server backup2.example.com:8080   backup;
}


server {
    location / {
        proxy_pass http://backend;
    }
}

注意:upstream只能定义在http

示例一:
node1节点的http模块下定义upstream:

upstream upservers {
    server node2.shellscript.cn:81;
    server node3.shellscript.cn;
}

编辑default.conf,注释掉之前定义的proxy_cache,在vim命令行模式下执行%s@[:space:]proxy_cache@#$@即可

default.conf下添加proxy_pass:

location /forum/ {
    #proxy_cache mycache;
    #proxy_cache_valid  200  1d;
    #proxy_cache_valid  301 302 10m;
    #proxy_cache_valid  any 1m;
    #proxy_cache_use_stale error timeout http_500 http_502 http_503 http_504;
    proxy_pass http://upservers/;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
}
    location ~* \.(jpg|png|gif)$ {
    #proxy_cache mycache;
    proxy_pass http://upservers;    ####注意这里upservers后面没有/字符,因为这是正则匹配下的location写法
    proxy_set_header X-Real-IP $remote_addr;
}

划粗体的为调用刚刚定义的upstream模块

重启nginx,客户端访问node1

[root@server ]# for((i=1;i<=4;i++));do curl node1.shellscript.cn/forum/;done
httpd on node2
http on node3
httpd on node2
http on node3
[root@server ]#

可以看到默认采用轮询算法

0.0.2 weight权重使用(加权轮询)

编辑upstream,在node2后面添加weight=2

upstream upservers {
    server node2.shellscript.cn:81 weight=2;
    server node3.shellscript.cn;
}

不添加weight则默认为1

重启nginx,客户端访问node1:

[root@server conf.d]# for((i=1;i<=6;i++));do curl node1.shellscript.cn/forum/;done
httpd on node2
httpd on node2
http on node3
httpd on node2
httpd on node2
http on node3
[root@server conf.d]#

很明显node2访问次数较多,说明weight已经生效

0.0.3 ip_hash算法

修改upstream如下:

upstream upservers {
    ip_hash;
    server node2.shellscript.cn:81 weight=2;
    server node3.shellscript.cn;
}

客户端访问:

[root@server conf.d]# for((i=1;i<=6;i++));do curl node1.shellscript.cn/forum/;done
httpd on node2
httpd on node2
httpd on node2
httpd on node2
httpd on node2
httpd on node2
[root@server conf.d]#

只要node2可以访问,就不会访问node3,但是不同的客户端会调往不同的upservers节点上

健康状态检测:max_failsfail_timeout
指定最大失败次数和超时时间,修改upstream如下:

upstream upservers {
    server node2.shellscript.cn:81 max_fails=2 fail_timeout=1;
    server node3.shellscript.cn max_fails=2 fail_timeout=1;
}

重启Nginx,因为此时weight权重一样,所以客户端访问依旧是轮询算法

此时把node2节点的http服务停掉以此模拟故障,接着客户端访问node1:

[root@server]# for((i=1;i<=4;i++));do curl node1.shellscript.cn/forum/;done
http on node3
http on node3
http on node3
http on node3
[root@server]#

重新启动node2http服务,客户端访问则恢复正常:

[root@server]# for((i=1;i<=4;i++));do curl node1.shellscript.cn/forum/;done
http on node3
httpd on node2
http on node3
httpd on node2
[root@server]#

0.0.4 downbackup

编辑upstream,标记node2backup备用节点:

upstream upservers {
    server node2.shellscript.cn:81 max_fails=2 fail_timeout=1 backup;
    server node3.shellscript.cn max_fails=2 fail_timeout=1;
}

重启nginx,客户端访问:

[root@server conf.d]# for((i=1;i<=4;i++));do curl node1.shellscript.cn/forum/;done
http on node3
http on node3
http on node3
http on node3
[root@server conf.d]#

此时只有node3响应,当node3出现故障后才会使用backup备用节点。不然一直使用node3

down则是标记该节点不可用。
关于ip_hash更详细的解释可参照官方文档:
http://nginx.org/en/docs/http/ngx_http_upstream_module.html#ip_hash

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转载请注明出处:北慕城南's Blog » Nginx加权轮询及upstream实战演练-