2. Use Cases and Fail Over Scenarios

This section provides information on the use cases and fail over scenarios for high availability in Hadoop.

Use Cases

This solution enables the following Hadoop system administration use cases:

Planned failure of the NameNode (for maintenance tasks like software or hardware upgrade)
Unplanned failure of the NameNode

Fail over scenarios

The solution deals with the following faults:

NameNode service failure
NameNode JVM failure
Hung NameNode daemon or hung operating system
NameNode operating system failure
Virtual machine failure
ESXi host failure
Failure of the NIC cards on ESXi hosts.
Network failure between ESXi hosts.
Note
Some double faults are not handled (such as failure of multiple ESXi hosts).

	Note
Some double faults are not handled (such as failure of multiple ESXi hosts).