Nginx 長連接keep_alive的具體使用
如何開啟并支持長連接
當(dāng)使用nginx作為反向代理時(shí),為了支持長連接,需要做到兩點(diǎn):
- 從client到nginx的連接是長連接
- 從nginx到server的連接是長連接
從HTTP協(xié)議的角度看,nginx在這個(gè)過程中,對(duì)于客戶端它扮演著HTTP服務(wù)器端的角色。而對(duì)于真正的服務(wù)器端(在nginx的術(shù)語中稱為upstream)nginx又扮演著HTTP客戶端的角色。
客戶端(Client)和 Nginx 保持長連接,兩個(gè)要求:
- client發(fā)送的HTTP請(qǐng)求要求keep alive
- nginx設(shè)置上支持keep alive
一、客戶端 與 Nginx 長連接配置
默認(rèn)情況下,nginx已經(jīng)自動(dòng)開啟了對(duì)client連接的keep alive支持。一般場景可以直接使用,但是對(duì)于一些比較特殊的場景,還是有必要調(diào)整個(gè)別參數(shù)。
keepalive_timeout 指令
keepalive_timeout指令的語法:
Syntax: keepalive_timeout timeout [header_timeout]; Default: keepalive_timeout 75s; Context: http, server, location
第一個(gè)參數(shù)設(shè)置keep-alive客戶端連接在服務(wù)器端保持開啟的超時(shí)值。值為0會(huì)禁用keep-alive客戶端連接??蛇x的第二個(gè)參數(shù)在響應(yīng)的header域中設(shè)置一個(gè)值“Keep-Alive: timeout=time”。這兩個(gè)參數(shù)可以不一樣。
注:默認(rèn)75s一般情況下也夠用,對(duì)于一些請(qǐng)求比較大的內(nèi)部服務(wù)器通訊的場景,適當(dāng)加大為120s或者300s。第二個(gè)參數(shù)通??梢圆挥迷O(shè)置。
keepalive_requests 指令
keepalive_requests指令用于設(shè)置一個(gè)keep-alive連接上可以服務(wù)的請(qǐng)求的最大數(shù)量。當(dāng)最大請(qǐng)求數(shù)量達(dá)到時(shí),連接被關(guān)閉。默認(rèn)是100。
這個(gè)參數(shù)的真實(shí)含義,是指一個(gè)keep alive建立之后,nginx就會(huì)為這個(gè)連接設(shè)置一個(gè)計(jì)數(shù)器,記錄這個(gè)keep alive的長連接上已經(jīng)接收并處理的客戶端請(qǐng)求的數(shù)量。如果達(dá)到這個(gè)參數(shù)設(shè)置的最大值時(shí),則nginx會(huì)強(qiáng)行關(guān)閉這個(gè)長連接,逼迫客戶端不得不重新建立新的長連接。
這個(gè)參數(shù)往往被大多數(shù)人忽略,因?yàn)榇蠖鄶?shù)情況下當(dāng)QPS(每秒請(qǐng)求數(shù))不是很高時(shí),默認(rèn)值100湊合夠用。但是,對(duì)于一些QPS比較高(比如超過10000QPS,甚至達(dá)到30000,50000甚至更高) 的場景,默認(rèn)的100就顯得太低。
簡單計(jì)算一下,QPS=10000時(shí),客戶端每秒發(fā)送10000個(gè)請(qǐng)求(通常建立有多個(gè)長連接),每個(gè)連接只能最多跑100次請(qǐng)求,意味著平均每秒鐘就會(huì)有100個(gè)長連接因此被nginx關(guān)閉。同樣意味著為了保持QPS,客戶端不得不每秒中重新新建100個(gè)連接。因此,如果用netstat命令看客戶端機(jī)器,就會(huì)發(fā)現(xiàn)有大量的TIME_WAIT的socket連接(即使此時(shí)keep alive已經(jīng)在client和nginx之間生效)。
因此對(duì)于QPS較高的場景,非常有必要加大這個(gè)參數(shù),以避免出現(xiàn)大量連接被生成再拋棄的情況,減少TIME_WAIT。
keepalive_requests 指令
默認(rèn)值1000,單個(gè)連接中處理的最大請(qǐng)求數(shù),超過這個(gè)數(shù),連接銷毀。
keepalive_disable 指令
不對(duì)某些瀏覽器建立長連接,默認(rèn):msie6
send_timeout 指令
兩次向客戶端寫操作之間的間隔 如果大于這個(gè)時(shí)間則關(guān)閉連接 默認(rèn)60s
此處有坑,注意耗時(shí)的同步操作有可能會(huì)丟棄用戶連接
該設(shè)置表示Nginx服務(wù)器與客戶端連接后,某次會(huì)話中服務(wù)器等待客戶端響應(yīng)超過10s,就會(huì)自動(dòng)關(guān)閉連接。
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65 65; #超過這個(gè)時(shí)間 沒有活動(dòng),會(huì)讓keepalive失效
keepalive_time 1h; # 一個(gè)tcp連接總時(shí)長,超過之后 強(qiáng)制失效
send_timeout 60;# 默認(rèn)60s 此處有坑??! 系統(tǒng)中 若有耗時(shí)操作,超過 send_timeout 強(qiáng)制斷開連接。 注意:準(zhǔn)備過程中,不是傳輸過程
keepalive_requests 1000; #一個(gè)tcp復(fù)用中 可以并發(fā)接收的請(qǐng)求個(gè)數(shù)二、Nginx 與 服務(wù)端長連接配置
2.1 在 upstream 中配置
keepalive 100;
向上游服務(wù)器的保留連接數(shù)(線程池的概念)
keepalive_timeout 65
連接保留時(shí)間(單位秒)
keepalive_requests 10000
一個(gè)tcp復(fù)用中 可以并發(fā)接收的請(qǐng)求個(gè)數(shù)
2.2 在 server 中配置
proxy_http_version 1.1; 配置http版本號(hào) 默認(rèn)使用http1.0協(xié)議,需要在request中增加”Connection: keep-alive“ header才能夠支持,而HTTP1.1默認(rèn)支持。 proxy_set_header Connection ""; 清楚close信息
三、壓力測(cè)試
3.1 【客戶端】 直連 【Nginx】
Server Software: nginx/1.21.6
Server Hostname: 192.168.44.102
Server Port: 80
Document Path: /
Document Length: 16 bytes
Concurrency Level: 30
Time taken for tests: 13.035 seconds
Complete requests: 100000
Failed requests: 0
Write errors: 0
Total transferred: 25700000 bytes
HTML transferred: 1600000 bytes
Requests per second: 7671.48 [#/sec] (mean)
Time per request: 3.911 [ms] (mean)
Time per request: 0.130 [ms] (mean, across all concurrent requests)
Transfer rate: 1925.36 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.4 0 12
Processing: 1 3 1.0 3 14
Waiting: 0 3 0.9 3 14
Total: 2 4 0.9 4 14
Percentage of the requests served within a certain time (ms)
50% 4
66% 4
75% 4
80% 4
90% 5
95% 5
98% 6
99% 7
100% 14 (longest request)3.2 【客戶端】 連接 【Nginx】 反向代理 【Nginx】
Server Software: nginx/1.21.6
Server Hostname: 192.168.44.101
Server Port: 80
Document Path: /
Document Length: 16 bytes
Concurrency Level: 30
Time taken for tests: 25.968 seconds
Complete requests: 100000
Failed requests: 0
Write errors: 0
Total transferred: 25700000 bytes
HTML transferred: 1600000 bytes
Requests per second: 3850.85 [#/sec] (mean)
Time per request: 7.790 [ms] (mean)
Time per request: 0.260 [ms] (mean, across all concurrent requests)
Transfer rate: 966.47 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.2 0 13
Processing: 3 8 1.4 7 22
Waiting: 1 7 1.4 7 22
Total: 3 8 1.4 7 22
Percentage of the requests served within a certain time (ms)
50% 7
66% 8
75% 8
80% 8
90% 9
95% 10
98% 12
99% 13
100% 22 (longest request)
3.3【客戶端】 直連 【Tomcat】
Server Software:
Server Hostname: 192.168.44.105
Server Port: 8080
Document Path: /
Document Length: 7834 bytes
Concurrency Level: 30
Time taken for tests: 31.033 seconds
Complete requests: 100000
Failed requests: 0
Write errors: 0
Total transferred: 804300000 bytes
HTML transferred: 783400000 bytes
Requests per second: 3222.38 [#/sec] (mean)
Time per request: 9.310 [ms] (mean)
Time per request: 0.310 [ms] (mean, across all concurrent requests)
Transfer rate: 25310.16 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.3 0 15
Processing: 0 9 7.8 7 209
Waiting: 0 9 7.2 7 209
Total: 0 9 7.8 7 209
Percentage of the requests served within a certain time (ms)
50% 7
66% 9
75% 11
80% 13
90% 18
95% 22
98% 27
99% 36
100% 209 (longest request)3.4 【客戶端】 連接 【Nginx】 反向代理 【Tomcat】并開啟keepalive
Server Software: nginx/1.21.6
Server Hostname: 192.168.44.101
Server Port: 80
Document Path: /
Document Length: 7834 bytes
Concurrency Level: 30
Time taken for tests: 23.379 seconds
Complete requests: 100000
Failed requests: 0
Write errors: 0
Total transferred: 806500000 bytes
HTML transferred: 783400000 bytes
Requests per second: 4277.41 [#/sec] (mean)
Time per request: 7.014 [ms] (mean)
Time per request: 0.234 [ms] (mean, across all concurrent requests)
Transfer rate: 33688.77 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.2 0 9
Processing: 1 7 4.2 6 143
Waiting: 1 7 4.2 6 143
Total: 1 7 4.2 6 143
Percentage of the requests served within a certain time (ms)
50% 6
66% 7
75% 7
80% 7
90% 8
95% 10
98% 13
99% 16
100% 143 (longest request)3.5 【客戶端】 連接 【Nginx】 反向代理 【Tomcat】不開啟keepalive
Server Software: nginx/1.21.6
Server Hostname: 192.168.44.101
Server Port: 80
Document Path: /
Document Length: 7834 bytes
Concurrency Level: 30
Time taken for tests: 33.814 seconds
Complete requests: 100000
Failed requests: 0
Write errors: 0
Total transferred: 806500000 bytes
HTML transferred: 783400000 bytes
Requests per second: 2957.32 [#/sec] (mean)
Time per request: 10.144 [ms] (mean)
Time per request: 0.338 [ms] (mean, across all concurrent requests)
Transfer rate: 23291.74 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.2 0 9
Processing: 1 10 5.5 9 229
Waiting: 1 10 5.5 9 229
Total: 1 10 5.5 9 229
Percentage of the requests served within a certain time (ms)
50% 9
66% 10
75% 11
80% 11
90% 13
95% 14
98% 17
99% 19
100% 229 (longest request)到此這篇關(guān)于Nginx 長連接keep_alive的具體使用的文章就介紹到這了,更多相關(guān)Nginx 長連接keep_alive內(nèi)容請(qǐng)搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家!
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