compressed format based on the input file suffix. Therefore, when it reads an input file, it is ***. when gz is used, it is estimated that the file is a file compressed with gzip, so it will try to read it using gzip.
Public CompressionCodecFactory (Configuration conf) {codecs = new TreeMap
If other compression methods are used, this can be configured in the core-site.xml
Or in the code
Conf. set ("io. compression. codecs "," org. apache
Although I have installed a Cloudera CDH cluster (see http://www.cnblogs.com/pojishou/p/6267616.html for a tutorial), I ate too much memory and the given component version is not optional. If only to study the technology, and is a single machine, the memory is small, or it is recommended to install Apache native cluster to play, production is naturally cloudera cluster, unless there is a very powerful operation.I have 3 virtual machine nodes this time
Description: Compile hadoop program using eclipse in window and run on hadoop. the following error occurs:
11/10/28 16:05:53 info mapred. jobclient: running job: job_201110281103_000311/10/28 16:05:54 info mapred. jobclient: Map 0% reduce 0%11/10/28 16:06:05 info mapred. jobclient: task id: attempt_201110281103_0003_m_000002_0, status: FailedOrg. apache.
Apache Hadoop and Hadoop biosphere
Hadoop is a distributed system infrastructure developed by the Apache Foundation.
Users can develop distributed programs without knowing the underlying details of the distribution. Make full use of the power of the cluster for high-speed o
This morning, I helped a new person remotely build a hadoop cluster (1. in versions X or earlier than 0.22), I am deeply touched. Here I will write down the simplest Apache hadoop construction method and provide help to new users. I will try my best to explain it in detail. Click here to view the avatorhadoop construction steps.
1. Environment preparation:
1 ). m
1. Preface
Hadoop RPC is mainly implemented through the dynamic proxy and reflection (reflect) of Java,Source codeUnder org. Apache. hadoop. IPC, there are the following main classes:
Client: the client of the RPC service
RPC: implements a simple RPC model.
Server: abstract class of the server
Rpc. SERVER: specific server class
Versionedprot
method names and parameters as the data transmission layer. The key to remote calling is that invocation implements the writable interface. Invocation writes the called methodname to out in the write (dataoutput out) function, and writes the number of parameters of the called method to out, at the same time, the classname of the parameter is written out one by one, and all parameters are written out one by one. This determines that the parameters in the method called through RPC are either simp
Install and deploy Apache Hadoop 2.6.0
Note: For this document, refer to the official documentation for the original article.
1. hardware environment
There are three machines in total, all of which use the linux system. Java uses jdk1.6.0. The configuration is as follows:Hadoop1.example.com: 172.20.115.1 (NameNode)Hadoop2.example.com: 172.20.1152 (DataNode)Hadoop3.example.com: 172.115.20.3 (DataNode)Hadoop4
the RM with several HA-related options and switches the Active/standby mode. The HA command takes the RM service ID set by the Yarn.resourcemanager.ha.rm-ids property as the parameter.$ yarn rmadmin-getservicestate rm1 Active $ yarn rmadmin-getservicestate RM2 StandbyIf automatic recovery is enabled, then you can switch commands without having to manually.$ yarn Rmadmin-transitiontostandby rm1 Automatic failover is enabled for [email protected] refusing to manually manage HA State, since it cou
Org. apache. hadoop. fs-Seekable, org. apache. commons
I should have read BufferedFSInputStream first, but it implements the Seekable and PositionedReadable interfaces. Let's look at these two interfaces first and then it will be easier to understand.
1 package org. apache. hadoo
Apache Hadoop is a distributed system infrastructure developed by the Apache Foundation. Enables users to develop reliable, scalable, distributed computing applications without knowing the underlying details of the distributed environment.The Apache Hadoop Framework allows u
Publish Apache Hadoop 2.6.0--heterogeneous storage, long-running service and rolling upgrade supportI am pleased to announce that the Apache Hadoop community has released the Apache 2.6.0:http://markmail.org/message/gv75qf3orlimn6kt!In particular, we are pleased with the thr
configuration.
Namenode
Run namenode. For more information about upgrade, rollback, and initialization, see upgrade rollback.
Usage: hadoop namenode [-format] [-upgrade] [-rollback] [-Finalize] [-importcheckpoint]
Command_option
Description
-Format
Format namenode. It starts namenode, formats it, and closes it.
-Upgrade
Namenode should be enabled to upgrade the distributed option of the new
Please refer to the original author, Xie, http://m.blog.itpub.net/30089851/viewspace-2121221/
1. Versionhadoop2.7.2+hbase1.1.5+hive2.0.0kylin-1.5.1kylin1.5 (apache-kylin-1.5.1-hbase1.1.3-bin.tar.gz)2.Hadoop Environment compiled to support snappy decompression LibraryRecompile HADOOP-2.7.2-SRC native to support snappy decompression compression library3. Environme
Apache Hadoop yarn (yarn = yet another Resource negotiator) has been a sub-project of Apache Hadoop since August 2012. Since this Apache Hadoop consists of the following four sub-projects:
Solve Exception: org. apache. hadoop. io. nativeio. NativeIO $ Windows. access0 (Ljava/lang/String; I) Z and other issues, ljavalangstring
I. Introduction
Windows Eclipse debugging Hadoop2 code, so we in windows Eclipse configuration hadoop-eclipse-plugin-2.6.0.jar plug-in, and when running Hadoop code appeared a serie
PrefaceHDFS provides administrators with a quota control feature for the directory that can controlname Quotas(The total number of files folders in the specified directory), orSpace Quotas(the upper limit for disk space). This paper explores the quota control characteristics of HDFs, and records the detailed process of various quota control scenarios. The lab environment is based on Apache Hadoop 2.5.0-cdh
Apache Hadoop is an efficient, scalable, distributed computing open source project.
The Apache Hadoop Library is a framework that allows for distributed processing of large datasets and compute clusters using a simple programming model. It is designed to scale from a single server to a thousands of machine, each offeri
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