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Hadoop – Modes of accessing HDFS

Modes of accessing HDFS: You can access Hadoop Distributed File System in 2 different ways.

  1. Direct Access
  2. Proxy based Access

Direct Access can be through ..

  1. Interactive Unix Shell commands
  2. Through Java and C++ APIs, clients retrieve metadata such as blocks locations from Namenode. Client directly access datanodes. HDFS accessing  through API is used in Map Reduce jobs.

Proxy Based Access through…

Clients communicated through a Proxy and it is strives to be language independent.

Several Proxy servers are packaged with Hadoop are

  1. Thrift – Interface definition language.
  2. WebHDFS REST – You can access HDFS through web, and the response is formatted in JSON, XML or Protocol Buffers.
  3. Avro – Data serialization mechanism.