Final answer:
A NameNode is a critical component of the Hadoop Distributed File System (HDFS) that manages the file system namespace and regulates access to files. Typically, there is one active NameNode in a Hadoop Cluster, but a standby NameNode can be configured for high availability and fault tolerance.
Step-by-step explanation:
NameNode
A NameNode is a critical component of the Hadoop Distributed File System (HDFS). It serves as the master node that manages the file system namespace and regulates access to files by clients.
In a Hadoop Cluster, there is typically only one active NameNode running at any given time. However, for high availability and fault tolerance, a standby NameNode can be configured to take over in case of failure.