AnsibleでWEBサーバの負荷テスト

Ansibleといえば構成管理ツールの一種という位置付けですが、複数のサーバを同時に制御できるという特徴から、サーバの負荷テストにも使うことができます。

負荷テスト用のツール

WEBサーバのベンチマークツールとして、Apach Benchmark か weighttp を用意します。Apach Benchmarkを使う場合はhttpd-toolsパッケージをインストールします。weightpは自分でビルドする必要があります。
これらのツールをAnsibleで複数のノードから同時かつ一斉に実行することで、WEBサーバの負荷テストを行うことができます。

Ansibleの設定

イベントリファイルにベンチマークツールを実行するホストを記述します。

[clients]
host1
host1
host3
・
・
host9
host10

また、並列処理数の設定 /etc/ansible/ansible.cfg でforks(平行して生成するプロセス数)にクライアント数以上の値を設定します。

[defaults]
inventory               = /etc/ansible/hosts
forks                   = 10

負荷テストの実行

ansibleコマンドでベンチマークツールを一斉に実行します。

【Apach Benchmarkの場合】

$ ansible clients -k -a "ab -c 100 -n 1000 http://192.168.10.1/"
SSH password: 
host1 | success | rc=0 >>
This is ApacheBench, Version 2.3 <$Revision: 1430300 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking 192.168.10.1 (be patient)


Server Software:        Boa/0.94.14rc21
Server Hostname:        192.168.10.1
Server Port:            80

Document Path:          /
Document Length:        702 bytes

Concurrency Level:      100
Time taken for tests:   8.167 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Non-2xx responses:      1000
Total transferred:      921000 bytes
HTML transferred:       702000 bytes
Requests per second:    122.44 [#/sec] (mean)
Time per request:       816.748 [ms] (mean)
Time per request:       8.167 [ms] (mean, across all concurrent requests)
Transfer rate:          110.12 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        2  215 1035.5      5    7032
Processing:     4  120 233.1     30    2060
Waiting:        4  119 233.1     30    2060
Total:          7  334 1087.9     39    7299

Percentage of the requests served within a certain time (ms)
  50%     39
  66%    142
  75%    189
  80%    233
  90%    356
  95%   1117
  98%   7128
  99%   7269
 100%   7299 (longest request)Completed 100 requests
Completed 200 requests
Completed 300 requests
Completed 400 requests
Completed 500 requests
Completed 600 requests
Completed 700 requests
Completed 800 requests
Completed 900 requests
Completed 1000 requests
Finished 1000 requests

・
・
・

host10 | success | rc=0 >>
This is ApacheBench, Version 2.3 <$Revision: 1430300 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking 192.168.10.1 (be patient)


Server Software:        Boa/0.94.14rc21
Server Hostname:        192.168.10.1
Server Port:            80

Document Path:          /
Document Length:        702 bytes

Concurrency Level:      100
Time taken for tests:   8.025 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Non-2xx responses:      1000
Total transferred:      921000 bytes
HTML transferred:       702000 bytes
Requests per second:    124.61 [#/sec] (mean)
Time per request:       802.535 [ms] (mean)
Time per request:       8.025 [ms] (mean, across all concurrent requests)
Transfer rate:          112.07 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        1  612 1858.0      3    7025
Processing:     7  180 133.5    162     627
Waiting:        7  179 133.5    161     627
Total:         15  792 1888.9    175    7532

Percentage of the requests served within a certain time (ms)
  50%    175
  66%    227
  75%    276
  80%    343
  90%   4140
  95%   7231
  98%   7483
  99%   7508
 100%   7532 (longest request)Completed 100 requests
Completed 200 requests
Completed 300 requests
Completed 400 requests
Completed 500 requests
Completed 600 requests
Completed 700 requests
Completed 800 requests
Completed 900 requests
Completed 1000 requests
Finished 1000 requests

【weighttpの場合】

$ ansible clients -k -a "weighttp -c 100 -n 1000 http://192.168.10.1/"
SSH password: 
host1 | success | rc=0 >>
weighttp - a lightweight and simple webserver benchmarking tool

starting benchmark...
spawning thread #1: 100 concurrent requests, 1000 total requests
progress:  10% done
progress:  20% done
progress:  30% done
progress:  40% done
progress:  50% done
progress:  60% done
progress:  70% done
progress:  80% done
progress:  90% done
progress: 100% done

finished in 4 sec, 696 millisec and 192 microsec, 212 req/s, 191 kbyte/s
requests: 1000 total, 1000 started, 1000 done, 0 succeeded, 1000 failed, 0 errored
status codes: 0 2xx, 0 3xx, 1000 4xx, 0 5xx
traffic: 921000 bytes total, 921000 bytes http, 0 bytes data

・
・
・

host10 | success | rc=0 >>
weighttp - a lightweight and simple webserver benchmarking tool

starting benchmark...
spawning thread #1: 100 concurrent requests, 1000 total requests
progress:  10% done
progress:  20% done
progress:  30% done
progress:  40% done
progress:  50% done
progress:  60% done
progress:  70% done
progress:  80% done
progress:  90% done
progress: 100% done

finished in 7 sec, 251 millisec and 565 microsec, 137 req/s, 124 kbyte/s
requests: 1000 total, 1000 started, 1000 done, 0 succeeded, 1000 failed, 0 errored
status codes: 0 2xx, 0 3xx, 1000 4xx, 0 5xx
traffic: 921000 bytes total, 921000 bytes http, 0 bytes data

実行結果に関しては、Apache Benchmark よりも weighttp の方がすっきりして見やすいかな。