juniorHadoop
What is a NameNode?
Updated May 16, 2026
Short answer
NameNode manages metadata of HDFS.
Deep explanation
It stores file-to-block mappings and controls access to data.
Real-world example
Central directory of a distributed file system.
Common mistakes
- Assuming NameNode stores actual data.
Follow-up questions
- What is checkpointing?
- What is HA NameNode?