nginx请求限制

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介绍

Nginx的请求限制分类：

  • 连接频率限制

    limit_conn_module。

  • 请求频率限制

    limit_req_module。

HTTP协议的连接与请求：

HTTP协议版本 连接关系
HTTP1.0 TCP不能复用
HTTP1.1 顺序性TCP复用
HTTP2.0 多路复用TCP复用

HTTP请求建立在一次TCP连接基础上，一次TCP请求至少产生一次HTTP请求。

一、连接限制

配置语法：

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Syntax:	limit_conn_zone key zone=name:size;
Default: --
Context: http
  • key：限制的key
  • zone：限制空间
  • name：限制空间的名字，为了limit_conn来调用的
  • size：申请空间的大小，单位是：M
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Syntax:	limit_conn zone number;
Default: --
Context: http,server,location
  • zone：就是需要调用的申请的zone的name
  • number：表示并发的限制，个数

二、请求限制

配置语法：

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Syntax:	limit_req_zone key zone=name:size rate=rate;
Default: --
Context: http
  • rate：速率，单位：秒（每秒几个）
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Syntax:	limit_req zone name [burst=number][nodelay];
Default: --
Context: http,server,location
  • burst：表示的是客户端在超过了指定的速率后，配置的遗留的请求数（配置为3）放到下一秒去执行，延迟响应，对客户端起到一个限速的作用
  • nodelay：超过3个的直接返回503

三、请求限制演示

  1. 配置修改

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    limit_conn_zone $binary_remote_addr zone=conn_zone:1m;
    limit_req_zone $binary_remote_addr zone=req_zone:1m rate=1r/s;
    server {
        location / {
        root   /opt/app/code;
    	#limit_conn conn_zone 1;
    	#limit_req zone=req_zone burst=3 nodelay;
    	#limit_req zone=req_zone burst=3;
    	limit_req zone=req_zone;
        index  index.html index.htm;
        }
    }

  2. 服务重载

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    root@node1 conf.d]# nginx -tc /etc/nginx/nginx.conf 
    nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
    nginx: configuration file /etc/nginx/nginx.conf test is successful
    [root@node1 conf.d]# nginx -s reload -c /etc/nginx/nginx.conf

  3. 压力测试

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    [root@node1 ~]# ab -n 20 -c 10 http://192.168.x.xxx/red.html
    • -n：发起的总请求数20个
    • -c：同时并发请求10个
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    Server Software:        nginx/1.16.1
    Server Hostname:        192.168.x.xxx
    Server Port:            80

    Document Path:          /red.html
    Document Length:        127 bytes

    Concurrency Level:      10
    Time taken for tests:   0.017 seconds
    Complete requests:      20 // 完成20个请求
    Failed requests:        19
       (Connect: 0, Receive: 0, Length: 19, Exceptions: 0)
    Write errors:           0
    Non-2xx responses:      19 // 19个请求返回非200状态
    Total transferred:      13431 bytes
    HTML transferred:       9513 bytes
    Requests per second:    1153.34 [#/sec] (mean)
    Time per request:       8.670 [ms] (mean)
    Time per request:       0.867 [ms] (mean, across all concurrent requests)
    Transfer rate:          756.37 [Kbytes/sec] received

    Connection Times (ms)
                  min  mean[+/-sd] median   max
    Connect:        0    1   0.5      1       2
    Processing:     2    7   4.2     10      12
    Waiting:        1    6   3.8      3      10
    Total:          2    8   3.9     11      12

    Percentage of the requests served within a certain time (ms)
      50%     11
      66%     11
      75%     12
      80%     12
      90%     12
      95%     12
      98%     12
      99%     12
     100%     12 (longest request)

  4. 查看错误日志

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    2020/03/29 17:25:13 [error] 6018#6018: *67 limiting requests, excess: 0.984 by zone "req_zone", client: 192.168.x.xxx, server: localhost, request: "GET /red.html HTTP/1.0", host: "192.168.x.xxx"
    2020/03/29 17:25:13 [error] 6018#6018: *68 limiting requests, excess: 0.984 by zone "req_zone", client: 192.168.x.xxx, server: localhost, request: "GET /red.html HTTP/1.0", host: "192.168.x.xxx"

    说明请求限制生效。

  5. 测试burst和nodelay

    打开配置：

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    limit_req zone=req_zone burst=3 nodelay;

    同样的压测条件，结果：

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    Server Software:        nginx/1.16.1
    Server Hostname:        192.168.1.104
    Server Port:            80

    Document Path:          /red.html
    Document Length:        127 bytes

    Concurrency Level:      10
    Time taken for tests:   0.012 seconds
    Complete requests:      20
    Failed requests:        16
       (Connect: 0, Receive: 0, Length: 16, Exceptions: 0)
    Write errors:           0
    Non-2xx responses:      16 // 减少到只有16个返回非200状态
    Total transferred:      12444 bytes
    HTML transferred:       8412 bytes
    Requests per second:    1707.80 [#/sec] (mean)
    Time per request:       5.855 [ms] (mean)
    Time per request:       0.586 [ms] (mean, across all concurrent requests)
    Transfer rate:          1037.69 [Kbytes/sec] received

    Connection Times (ms)
                  min  mean[+/-sd] median   max
    Connect:        0    1   0.4      1       2
    Processing:     3    3   0.8      3       5
    Waiting:        1    3   0.5      3       3
    Total:          3    4   0.8      5       5
    WARNING: The median and mean for the total time are not within a normal deviation
            These results are probably not that reliable.

    Percentage of the requests served within a certain time (ms)
      50%      5
      66%      5
      75%      5
      80%      5
      90%      5
      95%      5
      98%      5
      99%      5
     100%      5 (longest request)

四、连接限制演示

修改配置：

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limit_conn_zone $binary_remote_addr zone=conn_zone:1m;
limit_conn conn_zone 1;