背景介紹 上篇介紹了利用Nginx反向代理實現負載均衡,本文詳細講述Nginx下的幾種負載均衡策略。 輪詢 輪詢,顧名思義,就是輪流請求,基於上篇文章的介紹,我們將負載均衡策略聚焦於 文件的 。 在瀏覽器中對 連續發出請求,根據nginx請求日誌可以看出web02與web03訪問的次數是相同的。 加 ...
背景介紹
上篇介紹了利用Nginx反向代理實現負載均衡,本文詳細講述Nginx下的幾種負載均衡策略。
輪詢
輪詢,顧名思義,就是輪流請求,基於上篇文章的介紹,我們將負載均衡策略聚焦於default.conf
文件的upstream
。
upstream backend {
server web02:80;
server web03:80;
}
在瀏覽器中對localhost:8080
連續發出請求,根據nginx請求日誌可以看出web02與web03訪問的次數是相同的。
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" "-"
加權輪詢
加權輪詢是指基於上文中的輪詢,加上一定的權重,使得某個伺服器被轉發的次數更多一些,加權通過在IP後方拼接weight實現。
upstream backend {
server web02:80 weight=5;
server web03:80 weight=1;
}
weight值越大,所分配的請求就越多,根據nginx的請求日誌可以看出web02被訪問了8次,web03被訪問了兩次。
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
如果一個客戶端的請求可能被轉發到任何一臺伺服器,可能會導致每台伺服器都緩存了該客戶端的信息,比較浪費資源,ip_hash作用就是通過客戶端IP的前三個部分計算出key,以便將同一個客戶端的請求轉發到指定的伺服器中,配置的方法比較簡單,只需要在upstream
上方加一行代碼即可。
upstream backend {
ip_hash;
server web02:80;
server web03:80;
}
重覆請求了5次,通過日誌看出請求一直被鎖定在了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
這種模式是將url進行哈希,然後定位到具體的某一臺伺服器,相同的url永遠會被轉發到同一臺伺服器上。
upstream backend {
hash $request_uri;
server web02:80;
server web03:80;
}
通過瀏覽器訪問兩次http://localhost:8080
,通過日誌可以看到轉發被固定在了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" "-"
在鏈接後面拼接一些參數,就可以看到轉發發生了變化,固定在了web02,隨著參數的變化,請求也會採用輪詢的方式轉發給伺服器,但使用過的url再訪問就不會再變化了。
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" "-"