skydum

個人的な作業記録とか備忘録代わりのメモ

CentOS7 + apache + uwsgi + python3 + flaskでAPIサーバを構築する その2

Apache Flask uWSGI python

apache + uwsgi + flakeの負荷テストでのエラーについて

  • 参考: Apacheでリバースプロキシ、タイムアウトを上手にコントロール

  • クライアント → apache → uwsgiにアクセスを行う際にapacheからuwsgiにセッションを張る

  • uwsgiのAPIからのレスポンスがクライアントへ戻る
  • この時apacheとuwsgiのセッションは張ったままとなる
  • クライアントから⑧の2回目の接続の際にapacheが②の1回目のセッションを再利用しようとした瞬間、セッションが切断されるとエラーとなり、以下の様なエラーが/var/log/httpd/error_logに記録される
[Thu Jun 30 20:48:53.243189 2022] [proxy_http:error] [pid 3405] (20014)Internal error: [client 192.168.0.252:53838] AH01102: error reading status line from remote server 127.0.0.1:8080
[Thu Jun 30 20:48:53.243204 2022] [proxy:error] [pid 3405] [client 192.168.0.252:53838] AH00898: Error reading from remote server returned by /http

apacheの設定変更

  • /etc/httpd/conf.d/uwsgi.confの設定を以下のように変更する
  • SetEnv proxy-initial-not-pooled 1を追加
  • この設定を追加するとapacheとuwsgiの間の通信を行う際にセッションを張り直すのでエラーログに出ている接続しに行った瞬間にセッションが切断される問題が回避できる
# mod_proxy_uwsgiをapacheに組み込む
LoadModule proxy_uwsgi_module /usr/lib64/httpd/modules/mod_proxy_uwsgi.so

SetEnv proxy-initial-not-pooled 1

# フォワードプロキシをOffにする
ProxyRequests Off

ProxyPass /http http://127.0.0.1:8080
ProxyPassReverse /http http://127.0.0.1:8080

ProxyPass /unix uwsgi://127.0.0.1:9090
ProxyPassReverse /unix uwsgi://127.0.0.1:9090

もう一回負荷テスト

  • httpでapache + uwsgiと連携した場合

  • 設定変更後は前回の負荷テストで出ていたNon-2xx responses: 3555がなくなった

  • /http

# ab -c 100 -n 10000 http://192.168.0.150/http
This is ApacheBench, Version 2.3 <$Revision: 1843412 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking 192.168.0.150 (be patient)
Completed 1000 requests
Completed 2000 requests
Completed 3000 requests
Completed 4000 requests
Completed 5000 requests
Completed 6000 requests
Completed 7000 requests
Completed 8000 requests
Completed 9000 requests
Completed 10000 requests
Finished 10000 requests


Server Software:        Apache/2.4.6
Server Hostname:        192.168.0.151
Server Port:            80

Document Path:          /http
Document Length:        4 bytes

Concurrency Level:      100
Time taken for tests:   5.646 seconds
Complete requests:      10000
Failed requests:        0
Total transferred:      2010000 bytes
HTML transferred:       40000 bytes
Requests per second:    1771.08 [#/sec] (mean)
Time per request:       56.463 [ms] (mean)
Time per request:       0.565 [ms] (mean, across all concurrent requests)
Transfer rate:          347.64 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    0   0.3      0       6
Processing:     5   56  14.0     52     135
Waiting:        5   56  14.0     52     135
Total:          7   56  14.0     52     135

Percentage of the requests served within a certain time (ms)
  50%     52
  66%     57
  75%     62
  80%     66
  90%     76
  95%     85
  98%     96
  99%    103
 100%    135 (longest request)
  • socketでapache + uwsgiを連携した場合
  • 前回よりも多少遅くなった以外は問題なし
  • /unix
# ab -c 100 -n 10000 http://192.168.0.150/unix
This is ApacheBench, Version 2.3 <$Revision: 1843412 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking 192.168.0.151 (be patient)
Completed 1000 requests
Completed 2000 requests
Completed 3000 requests
Completed 4000 requests
Completed 5000 requests
Completed 6000 requests
Completed 7000 requests
Completed 8000 requests
Completed 9000 requests
Completed 10000 requests
Finished 10000 requests


Server Software:        Apache/2.4.6
Server Hostname:        192.168.0.150
Server Port:            80

Document Path:          /unix
Document Length:        4 bytes

Concurrency Level:      100
Time taken for tests:   5.927 seconds
Complete requests:      10000
Failed requests:        0
Total transferred:      2010000 bytes
HTML transferred:       40000 bytes
Requests per second:    1687.17 [#/sec] (mean)
Time per request:       59.271 [ms] (mean)
Time per request:       0.593 [ms] (mean, across all concurrent requests)
Transfer rate:          331.17 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    0   0.3      0      10
Processing:     5   59  17.5     54     170
Waiting:        4   54  16.1     50     160
Total:          7   59  17.6     54     171

Percentage of the requests served within a certain time (ms)
  50%     54
  66%     60
  75%     65
  80%     70
  90%     84
  95%     95
  98%    110
  99%    118
 100%    171 (longest request)

結論

  • socketでapche + uwsgiの連携を行うとエラーが出ない、またはhttpで連携する場合は以下の設定を入れる
  • 以下のエラーが出た場合はapacheの設定にSetEnv proxy-initial-not-pooled 1を入れると回避できる
  • 多少レスポンスが落ちる
  • 負荷テストの際にuwsgiのiniファイルの設定でprocesses, threadsの設定をいじるとRequests per secondの値が結構変わったのでuwsgiのパフォーマンスチューニングを行ってみる
[Thu Jun 30 20:48:53.243189 2022] [proxy_http:error] [pid 3405] (20014)Internal error: [client 192.168.0.252:53838] AH01102: error reading status line from remote server 127.0.0.1:8080
[Thu Jun 30 20:48:53.243204 2022] [proxy:error] [pid 3405] [client 192.168.0.252:53838] AH00898: Error reading from remote server returned by /http