Nginx16連環問，你被問到了嗎

{"type":"doc","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"作爲一個後端程序員，Nginx也是必備技能之一哦，作爲一個web服務器，Nginx的性能方面是很不錯的。本文總結或16個知識點，或者面試題分享給大家，後續還會繼續更新⛽️。"}]},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"1.什麼是nginx?"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Nginx是一個高性能的HTTP和反向代理服務器。同時也是一個 IMAP/POP3/SMTP 代理服務器。官方網站:http://nginx.org。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"2.nginx主要特徵？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"處理靜態文件，索引文件以及自動索引;打開文件描述符緩衝. 無緩存的反向代理加速，簡單的負載均衡和容錯. FastCGI，簡單的負載均衡和容錯.模塊化的結構。包括 gzipping, byte ranges, chunked responses,以及 SSI-filter 等filter。如果由 FastCGI 或其它代理服務器處理單頁中存在的多個 SSI，則這項處理可以並行 運行，而不需要相互等待。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"支持 SSL 和 TLSSNI."}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Nginx 它支持內核 Poll 模型，能經受高負載的考驗,有報告表明能支持高達 50,000 個併發連接數。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Nginx 具有很高的穩定性。例如當前 apache 一旦上到 200 個以上進程，web 響應速度就明顯非常緩慢了。而 Nginx 採取了分階段資源分配技術，使得它的 CPU 與內存佔用率非常低。nginx 官方表示保持 10,000 個沒有活動的連接，它只佔 2.5M 內存，所以類似 DOS 這樣的攻擊對 nginx 來說基本上是毫無用處的。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Nginx 支持熱部署。它的啓動特別容易, 並且幾乎可以做到 7*24 不間斷運行，即使運 行數個月也不需要重新啓動。對軟件版本進行進行熱升級。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Nginx 採用 master-slave 模型,能夠充分利用 SMP 的優勢，且能夠減少工作進程在此 盤 I/O 的阻塞延遲。當採用 select()/poll()調用時，還可以限制每個進程的連接數。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Nginx 代碼質量非常高，代碼很規範，手法成熟， 模塊擴展也很容易。特別值得一提的是強大的 Upstream 與 Filter 鏈。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Nginx 採用了一些 os 提供的最新特性如對 sendfile (Linux2.2+)，accept-filter (FreeBSD4.1+)，TCP_DEFER_ACCEPT (Linux 2.4+)的支持，從而大大提高了性能。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"免費開源，可以做高併發負載均衡。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"3.nginx 常用命令?"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"啓動 nginx 。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"停止 nginx -s stop 或 nginx -s quit 。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"重載配置 ./sbin/nginx -s reload(平滑重啓) 或 service nginx reload 。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"重載指定配置文件 .nginx -c /usr/local/nginx/conf/nginx.conf 。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"查看 nginx 版本 nginx -v 。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"檢查配置文件是否正確 nginx -t 。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"顯示幫助信息 nginx -h 。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"4.工作模式及連接數上限?"}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/3b/3b1cc23e007126a9c5bc06b9b212c55c.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"5.nginx負載均衡幾種算法？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"5種。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"1.輪詢模式（默認） 每個請求按時間順序逐一分配到不同的後端服務器，如果後端服務器down掉，能自動剔除。2.權重模式 指定輪詢機率，weight和訪問比率成正比，用於後端服務器性能不均的情況 3.IP_hash模式 （IP散列） 每個請求按訪問ip的hash結果分配，這樣每個訪客固定訪問一個後端服務器，可以解決session的問題。4.url_hash模式 5.fair模式 按後端服務器的響應時間來分配請求，響應時間短的優先分配。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"6.nginx有幾種進程模型?"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"分爲master-worker模式和單進程模式。在master-worker模式下，有一個master進程和至少一個的worker進程，單進程模式顧名思義只有一個進程。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"7.如何定義錯誤提示頁面？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"# 定義錯誤提示頁面"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/50/507302aeb310628283546442c73094b8.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"8.如何精準匹配路徑?"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"location =開頭表示精準匹配"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/a5/a5a0653f843b6d9ba6e15d065e157bf4.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"9.路徑匹配優先級？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"多個 location 配置的情況下匹配順序爲 首先匹配 =，其次匹配^~, 其次是按文件中順序的正則匹配，最後是交給 / 通用匹配。當 在匹配成功時候，停止匹配，按當前匹配規則處理請求。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"10.如何把請求轉發給後端應用服務器？"}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/22/22bfca6ec2acac28a0be82587ea2a8d4.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"11.如何根據文件類型設置過期時間？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/4a/4a365eed6191ec4e1ae8f9db2281b314.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"12.禁止訪問某個目錄？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/4f/4f560a6eea9cb559f39175cf20da514b.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"13.nginx負載均衡實現過程？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"首先在 http 模塊中配置使用 upstream 模塊定義後臺的 webserver 的池子，名爲 proxy-web，在池子中我們可以添加多臺後臺 webserver，其中狀態 檢查、調度算法都是在池子中配置;然後在 serverr 模塊中定義虛擬主機，但是這個虛擬主 機不指定自己的 web 目錄站點，它將使用 location 匹配 url 然後轉發到上面定義好的 web 池子中，最後根據調度策略再轉發到後臺 web server 上 。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"14.負載均衡配置？"}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/3f/3fd43a685cf0a0f7d856c442e6dba5b2.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"15.設置超時時間？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/88/886af3542e3bbd6be21918f24d4a4ae0.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"16.開啓壓縮功能好處？壞處？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"好處：壓縮是可以節省帶寬，提高傳輸效率"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"壞處：但是由於是在服務器上進行壓縮，會消耗服務器起源"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}}]}