Shulou(Shulou.com)06/02 Report--

By looking at the official documents of nginx, I saw three ways of nginx current restriction.

1 、 limit_conn_zone

2 、 limit_req_zone

3 、 ngx_http_upstream_module

The first two can only be limited to the client (that is, a single ip), and the documentation is very complete, but after testing, it is found that they still cannot achieve the results mentioned in the official documents (maybe there is something wrong with my test method).

Here is a brief introduction to the first two:

1 、 limit_conn_zone

1.1nginx configuration

Http {limit_conn_zone $binary_remote_addr zone=one:10m; server {. Limit_conn one 10;. }}

Where "limit_conn one 10" can be placed in the server layer for the entire server, or it can be placed in the location only for individual location.

This configuration indicates that the number of concurrent connections for clients can only be 10.

1.2 results

The ab tool 20 requests nginx concurrently, and you can see

Complete requests: 20

Failed requests: 9

(because the number of concurrent connections per ip in the nginx configuration is 10, and the reason why the number of successes in the result is + 1 is unknown; you can also see that 9 requests returned 503 in the log of nginx)

2 、 limit_req_zone

2.1 nginx configuration

Http {limit_req_zone $binary_remote_addr zone=req_one:10m rate=1r/s; server {. Limit_req zone=req_one burst=120;. }}

Where "limit_req zone=req_one burst=120" can be placed in the server layer for the entire server, or it can be placed in the location only for individual location.

Rate=1r/s means that each address can only be requested once per second, which means that the token bucket burst=120 has a total of 120 tokens, and only one new token is added per second.

3 、 ngx_http_upstream_module

3.1 introduction

As an excellent load balancing module, it is currently the most frequently used in my work. In fact, this module provides the back-end current-limiting function we need. According to the official documentation, the module has one parameter: max_conns can limit the server, but it can only be used in the commercial version of nginx. However, after the nginx1.11.5 version, the official has separated this parameter from the commercial version, that is, as long as we upgrade the widely used nginx1.9.12 version and 1.10 version in production (as you can see from the test, in the old version of nginx, if you add this parameter, the nginx service cannot be started).

3.2 configuration

Upstream xxxx {server 127.0.0.1:8080 max_conns=10; server 127.0.0.1:8081 max_conns=10;}

3.3 results (inconvenient screenshot)

Send 20, 30, 40 concurrent requests to nginx using the ab tool on each of the two machines:

You can see that no matter how many concurrent requests there are, there are only 12 successful requests, and the number of successful requests will be more than 2. At the same time, the number of successes in the test result of 1.2 is also + 1. Here are two machines. Based on this consideration, the number of successful machines is increased to three. Sure enough, the number of successful is 13. Here is a hypothesis that the number of successful requests will be + 1 based on the client's + 1 (this is only hypothetical)

Note: there are a few more important points. Max_conns is for a single server in upstream, not all; nginx has a parameter: worker_processes,max_conns is for each worker_processes

Installation steps of ab tools are attached (reproduced, unknown source)

# ab depends on the apr-util package. The installation command is: yum install apr-util # install dependent yumdownload tools in yum-utils If the yumdownload command is not found, you can yum install yum-utils cd / opt mkdir abtmp cd abtmp yum install yum-utils.noarch yumdownloader httpd-tools* rpm2cpio httpd-*.rpm | cpio-idmv # will generate a usr directory ab file in this usr directory # simple instructions for use. / ab-c 10000-n 10000 http://127.0.0.1/index.html #-c 100 that is, 10000 requests are sent at a time

The above is the whole content of this article, I hope it will be helpful to your study, and I also hope that you will support it.

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