Database Reference
In-Depth Information
Understanding the namenode UI
Hadoop provides web interfaces for each of its services. The namenode UI or the namen-
ode web interface is used to monitor the status of the namenode and can be accessed using
the following URL:
http://<namenode-server>:50070/
The namenode UI has the following sections:
•
Overview
: The general information section provides basic information of the na-
menode with options to browse the filesystem and the namenode logs.
The following is the screenshot of the
Overview
section of the namenode UI:
The
Cluster ID
parameter displays the identification number of the cluster. This
number is same across all the nodes within the cluster.
A
block pool
is a set of blocks that belong to a single namespace. The
Block Pool
Id
parameter is used to segregate the block pools in case there are multiple
namespaces configured when using HDFS federation. In HDFS federation, mul-
tiple namenodes are configured to scale the name service horizontally. These na-
menodes are configured to share datanodes amongst themselves. We will be ex-
ploring HDFS federation in detail a bit later.
•
Summary
: The following is the screenshot of the cluster's summary section from
the namenode web interface:
