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Nginx多种负载均衡策略搭建

程序员文章站 2023-01-01 14:35:25
背景介绍 上篇介绍了利用Nginx反向代理实现负载均衡,本文详细讲述Nginx下的几种负载均衡策略。 轮询 轮询,顾名思义,就是轮流请求,基于上篇文章的介绍,我们将负载均衡策略聚焦于 文件的 。 在浏览器中对 连续发出请求,根据nginx请求日志可以看出web02与web03访问的次数是相同的。 加 ......

背景介绍

上篇介绍了利用nginx反向代理实现负载均衡,本文详细讲述nginx下的几种负载均衡策略。

轮询

轮询,顾名思义,就是轮流请求,基于上篇文章的介绍,我们将负载均衡策略聚焦于default.conf文件的upstream

upstream backend {
    server web02:80;
    server web03:80;
}

在浏览器中对localhost:8080连续发出请求,根据nginx请求日志可以看出web02与web03访问的次数是相同的。

web01    | 172.24.0.1 - - [26/jun/2019:10:03:06 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web02    | 172.24.0.3 - - [26/jun/2019:10:03:06 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [26/jun/2019:10:03:07 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web03    | 172.24.0.3 - - [26/jun/2019:10:03:07 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web02    | 172.24.0.3 - - [26/jun/2019:10:05:25 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [26/jun/2019:10:05:25 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web03    | 172.24.0.3 - - [26/jun/2019:10:05:26 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [26/jun/2019:10:05:26 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web02    | 172.24.0.3 - - [26/jun/2019:10:05:27 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [26/jun/2019:10:05:27 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [26/jun/2019:10:05:27 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web03    | 172.24.0.3 - - [26/jun/2019:10:05:27 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"

加权轮询

加权轮询是指基于上文中的轮询,加上一定的权重,使得某个服务器被转发的次数更多一些,加权通过在ip后方拼接weight实现。

upstream backend {
    server web02:80 weight=5;
    server web03:80 weight=1;
}

weight值越大,所分配的请求就越多,根据nginx的请求日志可以看出web02被访问了8次,web03被访问了两次。

web01    | 172.24.0.1 - - [26/jun/2019:14:48:13 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web02    | 172.24.0.3 - - [26/jun/2019:14:48:13 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web02    | 172.24.0.3 - - [26/jun/2019:14:48:16 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [26/jun/2019:14:48:16 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [26/jun/2019:14:48:16 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web02    | 172.24.0.3 - - [26/jun/2019:14:48:16 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [26/jun/2019:14:48:17 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web03    | 172.24.0.3 - - [26/jun/2019:14:48:17 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [26/jun/2019:14:48:17 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web02    | 172.24.0.3 - - [26/jun/2019:14:48:17 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web02    | 172.24.0.3 - - [26/jun/2019:14:48:18 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [26/jun/2019:14:48:18 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [26/jun/2019:14:48:19 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web02    | 172.24.0.3 - - [26/jun/2019:14:48:19 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [26/jun/2019:14:48:19 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web02    | 172.24.0.3 - - [26/jun/2019:14:48:19 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [26/jun/2019:14:48:20 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web02    | 172.24.0.3 - - [26/jun/2019:14:48:20 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web03    | 172.24.0.3 - - [26/jun/2019:14:48:20 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [26/jun/2019:14:48:20 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"

ip_hash

如果一个客户端的请求可能被转发到任何一台服务器,可能会导致每台服务器都缓存了该客户端的信息,比较浪费资源,ip_hash作用就是通过客户端ip的前三个部分计算出key,以便将同一个客户端的请求转发到指定的服务器中,配置的方法比较简单,只需要在upstream上方加一行代码即可。

upstream backend {
    ip_hash;
    server web02:80;
    server web03:80;
}

重复请求了5次,通过日志看出请求一直被锁定在了web03上。

web01    | 172.24.0.1 - - [27/jun/2019:11:48:15 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web03    | 172.24.0.2 - - [27/jun/2019:11:48:15 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "172.24.0.1"
web01    | 172.24.0.1 - - [27/jun/2019:11:48:22 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web03    | 172.24.0.2 - - [27/jun/2019:11:48:22 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "172.24.0.1"
web03    | 172.24.0.2 - - [27/jun/2019:11:48:23 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "172.24.0.1"
web01    | 172.24.0.1 - - [27/jun/2019:11:48:23 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web03    | 172.24.0.2 - - [27/jun/2019:11:48:24 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "172.24.0.1"
web01    | 172.24.0.1 - - [27/jun/2019:11:48:24 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [27/jun/2019:11:48:24 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web03    | 172.24.0.2 - - [27/jun/2019:11:48:24 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "172.24.0.1"

url_hash

这种模式是将url进行哈希,然后定位到具体的某一台服务器,相同的url永远会被转发到同一台服务器上。

upstream backend {
    hash $request_uri;
    server web02:80;
    server web03:80;
}

通过浏览器访问两次http://localhost:8080,通过日志可以看到转发被固定在了web03。

web01    | 172.24.0.1 - - [27/jun/2019:11:58:31 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web03    | 172.24.0.4 - - [27/jun/2019:11:58:31 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web03    | 172.24.0.4 - - [27/jun/2019:11:58:38 +0000] "get / http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [27/jun/2019:11:58:38 +0000] "get / http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"

在链接后面拼接一些参数,就可以看到转发发生了变化,固定在了web02,随着参数的变化,请求也会采用轮询的方式转发给服务器,但使用过的url再访问就不会再变化了。

web02    | 172.24.0.4 - - [27/jun/2019:11:59:54 +0000] "get /?a=1 http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [27/jun/2019:11:59:54 +0000] "get /?a=1 http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web02    | 172.24.0.4 - - [27/jun/2019:11:59:55 +0000] "get /?a=1 http/1.0" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"
web01    | 172.24.0.1 - - [27/jun/2019:11:59:55 +0000] "get /?a=1 http/1.1" 304 0 "-" "mozilla/5.0 (macintosh; intel mac os x 10_14_2) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" "-"