1. Graceful Restartを
Node.jsで試してみた
yosuke_furukawa

2. Graceful Restartとは
• 直訳「優雅な再起動。」
存在している接続を殺さずに再起動する方法。

3. 考え方
Worker
connection
Cluster accept
Worker connections
Master connection
Worker
connection

4. 考え方
Worker
fork connection
Cluster accept
Worker connections
Master connection
Worker
connection

5. 考え方
old worker
connection
old worker
connection
Cluster old worker
Master connection

6. 考え方
restart event
old worker
connection
old worker
connection
Cluster old worker
Master connection

7. 考え方
restart event
old worker
cluster.disconnect connection
old worker
connection
Cluster old worker
Master connection

8. 考え方
restart event
old worker
cluster.disconnect connection
Stop accept
old worker
connection connections
Cluster old worker
Master connection

9. 考え方
restart event
old worker
cluster.disconnect connection
Stop accept
old worker
connection connections
Cluster old worker
Master connection
new worker
fork
new worker
Start accept
connections
new worker

10. 考え方
restart event
old worker
old worker
exit workers
Cluster old worker
Master
new worker
fork
new worker
Start accept
connections
new worker

11. イメージとしては・・・
こちらのレジにお並びください。
な、感じ。

12. Demo
• http://localhost:8000/
• ソースコード：https://gist.github.com/
3683651
• より完成度の高いライブラリ
Qilin：https://github.com/atsuya/qilin

13. another solution
• up モジュール(リクエスト時に毎回
Workerを割り振る考え方。Hotdeployに
最も近い方法。)
• 多少性能に難あり。
qilin up
time per reqs 2.332 [ms] 11.264 [ms]
reqs per sec 4287.65 887.79

14. Fin.
• Graceful RestartでNodeを本番環境でも
活用して行きましょう。