柚子快報邀請碼778899分享：Nginx 長連接keep

http://yzkb.51969.com/

如何開啟并支持長連接

當使用nginx作為反向代理時，為了支持長連接，需要做到兩點：

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在這個過程中，對于客戶端它扮演著HTTP服務器端的角色。而對于真正的服務器端（在nginx的術語中稱為upstream）nginx又扮演著HTTP客戶端的角色。

客戶端（Client）和 Nginx 保持長連接，兩個要求：

client發(fā)送的HTTP請求要求keep alivenginx設置上支持keep alive

一、客戶端 與 Nginx 長連接配置

????????默認情況下，nginx已經(jīng)自動開啟了對client連接的keep alive支持。一般場景可以直接使用，但是對于一些比較特殊的場景，還是有必要調整個別參數(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

第一個參數(shù)設置keep-alive客戶端連接在服務器端保持開啟的超時值。值為0會禁用keep-alive客戶端連接。可選的第二個參數(shù)在響應的header域中設置一個值“Keep-Alive: timeout=time”。這兩個參數(shù)可以不一樣。

注：默認75s一般情況下也夠用，對于一些請求比較大的內部服務器通訊的場景，適當加大為120s或者300s。第二個參數(shù)通?？梢圆挥迷O置。

keepalive_requests 指令

keepalive_requests指令用于設置一個keep-alive連接上可以服務的請求的最大數(shù)量。當最大請求數(shù)量達到時，連接被關閉。默認是100。

這個參數(shù)的真實含義，是指一個keep alive建立之后，nginx就會為這個連接設置一個計數(shù)器，記錄這個keep alive的長連接上已經(jīng)接收并處理的客戶端請求的數(shù)量。如果達到這個參數(shù)設置的最大值時，則nginx會強行關閉這個長連接，逼迫客戶端不得不重新建立新的長連接。

這個參數(shù)往往被大多數(shù)人忽略，因為大多數(shù)情況下當QPS(每秒請求數(shù))不是很高時，默認值100湊合夠用。但是，對于一些QPS比較高（比如超過10000QPS，甚至達到30000,50000甚至更高) 的場景，默認的100就顯得太低。

簡單計算一下，QPS=10000時，客戶端每秒發(fā)送10000個請求(通常建立有多個長連接)，每個連接只能最多跑100次請求，意味著平均每秒鐘就會有100個長連接因此被nginx關閉。同樣意味著為了保持QPS，客戶端不得不每秒中重新新建100個連接。因此，如果用netstat命令看客戶端機器，就會發(fā)現(xiàn)有大量的TIME_WAIT的socket連接(即使此時keep alive已經(jīng)在client和nginx之間生效)。

因此對于QPS較高的場景，非常有必要加大這個參數(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

默認值1000，單個連接中處理的最大請求數(shù)，超過這個數(shù)，連接銷毀。

keepalive_disable 指令

不對某些瀏覽器建立長連接，默認：msie6

send_timeout 指令

兩次向客戶端寫操作之間的間隔 如果大于這個時間則關閉連接 默認60s

此處有坑，注意耗時的同步操作有可能會丟棄用戶連接

該設置表示Nginx服務器與客戶端連接后，某次會話中服務器等待客戶端響應超過10s，就會自動關閉連接。

http {

include mime.types;

default_type application/octet-stream;

sendfile on;

keepalive_timeout 65 65; #超過這個時間 沒有活動，會讓keepalive失效

keepalive_time 1h; # 一個tcp連接總時長，超過之后 強制失效

send_timeout 60;# 默認60s 此處有坑??！ 系統(tǒng)中 若有耗時操作，超過 send_timeout 強制斷開連接。 注意：準備過程中，不是傳輸過程

keepalive_requests 1000; #一個tcp復用中 可以并發(fā)接收的請求個數(shù)

二、Nginx 與 服務端長連接配置

2.1 在 upstream 中配置

keepalive 100;

向上游服務器的保留連接數(shù)（線程池的概念）

keepalive_timeout 65

連接保留時間（單位秒）

keepalive_requests 10000

一個tcp復用中 可以并發(fā)接收的請求個數(shù)

2.2 在 server 中配置

proxy_http_version 1.1;

配置http版本號

默認使用http1.0協(xié)議，需要在request中增加”Connection： keep-alive“ header才能夠支持，而HTTP1.1默認支持。

proxy_set_header Connection "";

清楚close信息

三、壓力測試

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)

柚子快報邀請碼778899分享：Nginx 長連接keep

http://yzkb.51969.com/

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