hadoop hdfs commands

Hadoop reading Notes (i) Introduction to Hadoop: http://blog.csdn.net/caicongyang/article/details/39898629Hadoop Reading notes (ii) the shell operation of HDFs :http://blog.csdn.net/caicongyang/article/details/41253927JAVA URL Operation HDFsOperatebyurl.javaPackage Hdfs;import Java.io.inputstream;import Java.net.url;im

1. Add a new document to any directory. The content is freely enteredmkdir words2. Create a new file entry directory in HDFs./hdfs Dfs-mkdir/test3. Upload the new document (/home/hadoop/test/words) to the new (test) HDFs directory./hdfs dfs-put/home/

1. Import the Hadoop jar packageAdd the hadoop/share/common/directory, hadoop/share/common/lib/directory, hadoop/hdfs/directory, and the next jar package to eclipse.2. Start Encoding CallStaticFileSystem fs=NULL; Public Static voidMain (string[] args) throws Exception {//T

HDFS is a hadoop distributed filesystem, A hadoop distributed file system. When the data is as big as one machine and cannot be stored, it should be distributed to multiple machines. The file system that manages the storage space on multiple computers through the network is called a distributed file system. The complexity of network programs makes distributed fil

HDFS super permission group is supergroup. the user who starts hadoop is usually superuser. DFS. Data. dir /Opt/data1/HDFS/data,/Opt/data2/HDFS/data,/Opt/data3/HDFS/data,... Real datanode data storage path. Multiple hard disks can be written and separated by

PackageCn.itcast.bigdata.hdfs;ImportJava.net.URI;ImportJava.util.Iterator;ImportJava.util.Map.Entry;Importorg.apache.hadoop.conf.Configuration;ImportOrg.apache.hadoop.fs.FileStatus;ImportOrg.apache.hadoop.fs.FileSystem;ImportOrg.apache.hadoop.fs.LocatedFileStatus;ImportOrg.apache.hadoop.fs.Path;ImportOrg.apache.hadoop.fs.RemoteIterator;ImportOrg.junit.Before;Importorg.junit.Test;/*** * Client to operate HDFS, there is a user identity * By default, the

[TOC] Hadoop HDFS Java APIMainly Java operation HDFs Some of the common code, the following direct code:Package Com.uplooking.bigdata.hdfs;import Org.apache.hadoop.conf.configuration;import org.apache.hadoop.fs.*; Import Org.apache.hadoop.fs.permission.fspermission;import Org.apache.hadoop.io.ioutils;import org.junit.After; Import Org.junit.before;import or

, success!About emptying the size of the space, after emptying the logs, or using 15G, there should be other places to continue to empty, welcome advice![Email protected] hadoop]# df-ahfilesystem Size used Avail use% mounted on/dev/sda2 18G 15G 2.1G 88%/proc 0 0 0 - /procsysfs 0 0 0 - /sysdevpts 0 0 0 - /dev/ptstmpfs 9

Problem Description:Hadoop in the virtual machine under the Linux systemLocal files are uploaded to the specified directory on the Hadoop platform by writing code locally through eclipseThe code is as follows:@Test Public voidUpload ()throwsIOException {Configuration conf=NewConfiguration (); Conf.set ("Fs.defaultfs", "Hdfs://lujie01:9000/"); FileSystem FS=filesystem.get (conf); Path Path=NewPath ("

Environment configurationYou first need to configure the Hadoop_classpath variable in hadoop-env.sh:Export Hadoop_classpath=/home/hadoop/hadoop-1.2.1/myclassConfigure Java_home in. Bash_profile and take effectTest programUrlcat.javaimportorg.apache.hadoop.fs.fsurlstreamhandlerfactory;importorg.apache.hadoop.io.ioutils ;importjava.io.inputstream;importjava.net.url

What is 1.HDFS?The Hadoop Distributed File System (HDFS) is designed to be suitable for distributed file systems running on general-purpose hardware (commodity hardware). It has a lot in common with existing Distributed file systems.Basic Concepts in 2.HDFS(1) blocks (block)"Block" is a fixed-size storage unit,

Configuration file m103 Replace with the HDFs service address.To use the Java client to access the file on the HDFs, have to say is the configuration file Hadoop-0.20.2/conf/core-site.xml, originally I was here to eat a big loss, so I am not even hdfs, file can not be created, read. Configuration item: H

Hadoop provides us with an API to access HDFs using C language , which is briefly described below:Environment:ubuntu14.04 hadoop1.0.1 jdk1.7.0_51AccessHDFsfunction is primarily defined in theHdfs.hfile, the file is located in thehadoop-1.0.1/src/c++/libhdfs/folder, and the corresponding library file is located in the hadoop-1.0.1/c++/linux-amd64-64/lib/director

ObjectiveWithin Hadoop, there are many types of file systems implemented, and of course the most used is his distributed file system, HDFs. However, this article does not talk about the master-slave architecture of HDFS, because these things are much more spoken on the internet and in the information books. So, I decided to take my personal learning, to say somet

Common hadoop hdfs operations java code Package hadoopTest; import java. io. IOException; import java. util. logging; import org. apache. hadoop. conf. configuration; import org. apache. hadoop. fs. blockLocation; import org. apache. hadoop. fs. FSDataInputStream; import org

Use 3 machines to build HDFS fully distributed cluster 201 (NameNode), 202 (DataNode), 203 (DataNode)Overall architectureNameNode (192.168.1.201)DataNode (192.168.1.202,192.168.1.203)Secondarynamenode (192.168.1.202)1. Download the Hadoop package from the official website and upload it to the Linux systemHadoop-1.2.1.tar.gzExtractTAR-ZXVF hadoop-1.2.1.tar.gz Linu

In Hadoop, ACLs are used to manage HDFs permissions, and ACL permissions are added to the rights control in hadoop2.4, like Linux ACL permissions 1, modify the HDFS permission configuration 2. Permission Configuration Assigning permissions to the owning master and group Sudo-u HDFs