http://doc.mapr.com/display/MapR/Installing+MapR+Software#InstallingMapRSoftware-getpackagesStep1:PreparePackagesandRepositories Change to the root user or use sudo. Create a text file called maprtech.repo in the /etc/yum.repos.d/ directory... Read More | Share it now!
Category Archives: Hadoop
klist
klist SYNOPSIS klist ]] ] DESCRIPTION klist lists the Kerberos principal and Kerberos tickets held in a credentials cache, or the keys held in a keytab file. OPTIONS -e Displays the encryption types of the session key and the ticket for... Read More | Share it now!
MapReduce jobs get stuck in Accepted state never Run
The settings I have (on my very small experimental boxes) in my yarn-site.xml: <property> <name>yarn.nodemanager.resource.memory-mb</name> <value>2200</value> <description>Amount of physical memory, in MB,... Read More | Share it now!
How To Configure NameNode High Availability
https://docs.hortonworks.com/HDPDocuments/Ambari-2.2.1.1/bk_Ambari_Users_Guide/content/_how_to_configure_namenode_high_availability.html 1.1. How To Configure NameNode High Availability Check to make sure you have at least three hosts in... Read More | Share it now!
hadoop.mapred vs hadoop.mapreduce?
Why are there two separate packages map-reduce package in Apache’s hadoop package... Read More | Share it now!
Class Not Found Exception in Mapreduce wordcount job
2016-07-18 11:51:36,921 WARN org.apache.hadoop.mapred.YarnChild: Exception running child : java.lang.RuntimeException: java.lang.ClassNotFoundException: Class MyNLineInputFormat$MyNLineInputFormatMapper not found at... Read More | Share it now!
Hadoop中的NLineInputFormat
http://blog.csdn.net/lzm1340458776/article/details/42747443 一：背景 NLineInputFormat也是FileInputFormat的子类，它是根据行数来划分InputSplit的，而不是像TextInputFormat那样依赖分片大小和行的长度。也就是说，TextInputFormat当一行很长或分片很小时，获取的分片很可能只包含很少的K-V对，这样一个MapTask处理的K-V对就很少，这是不太理想的。因此我们可以使用NLineInputFormat来控制一个MapTask处理的K-V对，这是通过分割InputSplit时按行数分割的方法来实现的，关键是通过mapreduce.input.lineinputformat.linespermap来设置这个行数。 二：技术实现 代码如下： /** ... Read More | Share it now!
Hadoop 中JobClient 里 submitJob(JobConf) 和 runJob(JobConf) 的区别
Hadoop提交 Job到JobTracker的时候，需要通过JobClient.runJob(JobConf) 或者 JobClient.submitJob(JobConf)... Read More | Share it now!
Install MapR 4.0.2 (or other version before 4.2)
Change to the root user or use sudo. Create a text file called maprtech.repo in the /etc/yum.repos.d/ directory with the following content, replacing v4.0.2 with the version of MapR that you want to install: name=MapR... Read More | Share it now!
使用 FileSystem JAVA API 对 HDFS 进行读、写、删除等操作
Hadoop文件系统 基本的文件系统命令操作, 通过hadoop fs... Read More | Share it now!