August 2015
Intermediate to advanced
312 pages
7h 28m
Japanese
Content preview from 初めてのSpark
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
216
10 章 Spark Streaming
10.6.4
レーバのフールトトレラン
もう
1
つの重要な考慮事項として、レシーバを実行しているワーカーのフォールトトレランス
があります。そういった障害が起きた場合、
Spark Streaming
は障害のあったレシーバをクラスタ
内の他のノード上で再起動します。ただし、障害のあったレシーバが受信したデータを失う可能性
の有無は、ソースの性質（データを再送できるかどうか）とレシーバの実装（データの受信をソー
スに通知するかどうか）によります。例えば
Flume
を使っている場合、
2
つのレシーバの主な違
いの
1
つは、データの損失がないことを保証するかどうかです。レシーバが
sink
からプルを行う
動作モデルでは、
Spark
は内部で複製された要素を、
1
度だけ取り除きます。レシーバへプッシュ
される動作モデルでは、データが複製される前にレシーバに障害があれば、データの一部が失われ
ることがあります。概して、データが一切失われないことを保証するためには、いかなるレシーバ
を使う場合でも、上流のソースのフォールトトレランス（トランザクションを使うかどうか）も考
慮に入れなければなりません。
概して、レシーバは次のようなことを保証します。
•
信頼できるファイルシステムから読み取ったすべてのデータ（例えば
StreamingContext.
hadoopFiles
で読み取ったデータ）は、下位層のファイルシステムが複製を行っているこ
とから、信頼性があります。
Spark Streaming ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.