start hdfs

Sudo addgroup hadoop # Add a hadoop GroupSudo usermod-a-g hadoop Larry # Add the current user to the hadoop GroupSudo gedit ETC/sudoers # Add the hadoop group to sudoerHadoop all = (all) All after root all = (all) All Modify hadoop Directory PermissionsSudo chown-r Larry: hadoop/home/Larry/hadoop Sudo chmod-r 755/home/Larry/hadoop Modify HDFS PermissionsSudo bin/hadoop DFS-chmod-r 755/Sudo bin/hadoop DFS-ls/ Modify the

Add a Hadoop group sudo addgroup Hadoop Add the current user Larry to the Hadoop groupsudo usermod-a-G Hadoop Larry Add Hadoop Group to Sudoersudo gedit etc/sudoersHadoop all= (All) after Root all= (all) Modify the permissions for the Hadoop directorysudo chown-r larry:hadoop/home/larry/hadoop Modify permissions for HDFssudo chmod-r 755/home/larry/hadoopsudo bin/hadoop dfs-chmod-r 755/sudo bin/hadoop dfs-ls/ Modify the owner of the HDFs filesudo bin/

HA-Federation-HDFS + Yarn cluster deployment mode After an afternoon's attempt, I finally set up the cluster, and it didn't feel much necessary to complete the setup. So I should study it and lay the foundation for building the real environment. The following is a cluster deployment of Ha-Federation-hdfs + Yarn. First, let's talk about my Configuration: The four nodes are started respectively: 1. bkjia117:

Transferred from: http://www.cnblogs.com/tgzhu/p/5788634.htmlWhen configuring an HBase cluster to hook HDFs to another mirror disk, there are a number of confusing places to study again, combined with previous data; The three cornerstones of big Data's bottom-up technology originated in three papers by Google in 2006, GFS, Map-reduce, and Bigtable, in which GFS, Map-reduce technology directly supported the birth of the Apache Hadoop project, BigTable

Not much to say, directly on the code.CodePackage zhouls.bigdata.myWholeHadoop.HDFS.hdfs7;Import java.io.IOException;Import Java.net.URI;Import java.net.URISyntaxException;Import org.apache.hadoop.conf.Configuration;Import Org.apache.hadoop.fs.FSDataInputStream;Import Org.apache.hadoop.fs.FSDataOutputStream;Import Org.apache.hadoop.fs.FileStatus;Import Org.apache.hadoop.fs.FileSystem;Import Org.apache.hadoop.fs.FileUtil;Import Org.apache.hadoop.fs.Path;Import Org.apache.hadoop.fs.PathFilter;Impo

] process]# CD 437-hdfs-namenode[email protected] 437-hdfs-namenode]# cat log4j.properties |grep Log4j.appender.RFA.layout.ConversionPatternlog4j.appender.rfa.layout.conversionpattern={"Time": "%d{yyyy-mm-dd hh:mm:ss,sss}", "LogType": "%p", "Loginfo": "%c: %m "}%n[Email protected] 437-hdfs-namenode]#4.2 Check Log to[Email protected] 437-

Requirements are as follows:Generate an approximately 100-byte text file on your local filesystem, write a program (which can take advantage of the Java API or C API), read the file, and write its 第101-120 byte content to HDFs as a new file.ImportJava.io.File;ImportJava.io.FileOutputStream;Importjava.io.IOException;ImportJava.io.OutputStream; Public classShengchen { Public Static voidMain (string[] args)throwsIOException {//TODO auto-generated Method

This is a major chat about Hadoop Distributed File System-hdfs Outline: 1.HDFS Design Objectives The Namenode and Datanode inside the 2.HDFS. 3. Two ways to operate HDFs 1.HDFS design target hardware error Hardware errors are normal rather than abnormal. (Every time I read t

itself.Datanode is a data storage node that is responsible for storage management on the physical node on which it resides. The file store in HDFs is stored in blocks (block), and the default size is 64MB.Client operation data, only through Namenode to obtain the physical location of the Datanode node, for the write/read data of the specific operation, Namenode will not participate, all by the datanode responsible.Since there is only one Namenode nod

implementation of two HDFS cluster transfer data betweenIf you use the new WEBHDFS protocol (instead of HFTP), you can use the HTTP protocol to communicate with both the source and target clusters without causing any incompatibility problems[Email protected] ~]$ Hadoop distcp webhdfs://hadoop1:50070/weather webhdfs://hadoop3:50070/middleAs shown below　　　　3. Other common shell operations for Hadoop administratorsMastering how the shell accesses

1. File Stream Write HDFs public static void Putfiletohadoop (String hadoop_path, byte[] filebytes) throws Exception { Configuration conf = New Configuration (); FileSystem fs = Filesystem.get (Uri.create (Hadoop_path), conf); Path PATH = new Path (hadoop_path); Fsdataoutputstream out = fs.create (path); Control number of copies-WT fs.setreplication (Path, (short) 1); Out.write (filebytes); Out.close (); } Author

1. Problem: When the input of a mapreduce program is a lot of mapreduce output, since input defaults to only one path, these files need to be merged into a single file. This function copymerge is provided in Hadoop. The function is implemented as follows: public void Copymerge (string folder, string file) { path src = new Path (folder); Path DST = new path (file); Configuration conf = new configuration (); try { Fileutil.copymerge (src.getfilesystem (conf), SRC, dst.getfilesys

namenode itself is still a single point of failure-If namenode fails, all clients, mapreduce jobs cannot read, write, and view files normally, because namenode is the only database that maintains namespace metadata and provides file-to-block ing. to recover from a failed namenode, the administrator should start a new namenode and configure datanode and the user to use this new namenode. This new namenode does not work until it has completed the foll

between them is the following diagram: NN managed the HDFs two most important relationships: The directory file tree structure and the corresponding relationship between the file and the data block: It is persisted to the physical storage, the filename is called Fsimage. The DN corresponds to the data block, that is, the DN in which the data block is stored: When the DN is started, the data blocks it maintains are reported over NN. This is dynamic

the specified HDFS. The specific implementation is as follows: Package com.hebut.file; Import org.apache.hadoop.conf.Configuration; Import Org.apache.hadoop.fs.FileStatus; Import Org.apache.hadoop.fs.FileSystem; Import Org.apache.hadoop.fs.Path; public class Listallfile { public static void Main (string[] args) throws Exception { Configuration conf=new configuration (); FileSystem hdfs