Hadoop can be run in 3 different modes. Different modes of Hadoop are
- Default mode of Hadoop
- HDFS is not utilized in this mode.
- Local file system is used for input and output
- Used for debugging purpose
- No Custom Configuration is required in 3 hadoop(mapred-site.xml,core-site.xml, hdfs-site.xml) files.
- Standalone mode is much faster than Pseudo-distributed mode.
Pseudo Distributed Mode(Single Node Cluster)
- Configuration is required in given 3 files for this mode
- Replication factory is one for HDFS.
- Here one node will be used as Master Node / Data Node / Job Tracker / Task Tracker
- Used for Real Code to test in HDFS.
- Pseudo distributed cluster is a cluster where all daemons are
running on one node itself.
Fully distributed mode (or multiple node cluster)
- This is a Production Phase
- Data are used and distributed across many nodes.
- Different Nodes will be used as Master Node / Data Node / Job Tracker / Task Tracker
How to Switch from One Mode to Another Mode