Cloudera
CCA-500 · Question #42
Your Hadoop cluster contains nodes in three racks. You have not configured the dfs.hosts property in the NameNode's configuration file. What results?
The correct answer is C. Any machine running the DataNode daemon can immediately join the cluster. The dfs.hosts is just an "extra security layer", if that doesn't exist all machines running a DataNode daemon can join into the cluster (if the nameresolution works fine).
Configuration
Question
Your Hadoop cluster contains nodes in three racks. You have not configured the dfs.hosts property in the NameNode's configuration file. What results?
Options
- AThe NameNode will update the dfs.hosts property to include machines running the DataNode
- BNo new nodes can be added to the cluster until you specify them in the dfs.hosts file
- CAny machine running the DataNode daemon can immediately join the cluster
- DPresented with a blank dfs.hosts property, the NameNode will permit DataNodes specified in
How the community answered
(22 responses)- A9% (2)
- B5% (1)
- C77% (17)
- D9% (2)
Explanation
The dfs.hosts is just an "extra security layer", if that doesn't exist all machines running a DataNode daemon can join into the cluster (if the nameresolution works fine).
Topics
#dfs.hosts#DataNode#cluster membership#NameNode configuration
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