ayushtkn commented on PR #5396: URL: https://github.com/apache/hadoop/pull/5396#issuecomment-1433632089
The active NN knows that which datanode is dead. That is how it shows in the UI as well. There would be some param in the JMX which must be telling the state of the datanode to the active namenode. I can pull that out for you, if you want, but it is in the UI, so there would be a metric for sure, just being lazy to check the code again:  Datanode has metrics and you know post what time it is declared dead. Any service can have periodic health checks and have a check. Anyway you have a service which checks if datanode is dead and restarts, some logics here and there in that to have a periodic check to shoot a shutdown as well, should do. <img width="1273" alt="image" src="https://user-images.githubusercontent.com/25608848/219470918-db38d602-984f-4baa-9860-aee19b2af646.png";> Code point of view implementing such a logic sounds very naive to me. or may be minimal effort thing Not dragging the use case list either, because there ain't no end to that, client was X and he was in Y state and blah blah, datanode block reconstruction works, around block movements and it won't end.... -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
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