Package org.apache.hadoop.hdfs.server.namenode.startupprogress
@Private
package org.apache.hadoop.hdfs.server.namenode.startupprogress
This package provides a mechanism for tracking NameNode startup
progress. The package models NameNode startup as a series of
Phases,
with each phase further sub-divided into multiple Steps. All phases
are coarse-grained and typically known in advance, implied by the structure of
the NameNode codebase (example: loading fsimage). Steps are more granular and
typically only known at runtime after startup begins (example: loading a
specific fsimage file with a known length from a particular location).
StartupProgress provides a thread-safe data structure for
recording status information and counters. Various parts of the NameNode
codebase use this to describe the NameNode's activities during startup.
StartupProgressView provides an immutable, consistent view of the
current state of NameNode startup progress. This can be used to present the
data to a user.
StartupProgressMetrics exposes startup progress information via JMX
through the standard metrics system.-
ClassDescriptionIndicates a particular phase of the namenode startup sequence.StartupProgress is used in various parts of the namenode codebase to indicate startup progress.Allows a caller to increment a counter for tracking progress.Links
StartupProgressto aMetricsSourceto expose its information via JMX.StartupProgressView is an immutable, consistent, read-only view of namenode startup progress.Indicates run status of aPhase.A step performed by the namenode during aPhaseof startup.Indicates a particular type ofStep.