May 2018
Beginner to intermediate
482 pages
11h 42m
English
Content preview from Big Data Analytics with Hadoop 3
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High availability
The loss of NameNodes can crash the cluster in both Hadoop 1.x as well as Hadoop 2.x. In Hadoop 1.x, there was no easy way to recover, whereas Hadoop 2.x introduced high availability (active-passive setup) to help recover from NameNode failures.
The following diagram shows how high availability works:
In Hadoop 3.x you can have two passive NameNodes along with the active node, as well as five JournalNodes to assist with recovery from catastrophic failures:
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NameNode machines: The machines on which you run the active and standby NameNodes. They should have equivalent hardware to each other and to what would be used in a non-HA ...