First, ready to run the required jar package1) Avro-1.7.4.jar2) Commons-cli-1.2.jar3) Commons-codec-1.4.jar4) Commons-collections-3.2.1.jar5) Commons-compress-1.4.1.jar6) Commons-configuration-1.6.jar7) Commons-io-2.4.jar8) Commons-lang-2.6.jar9) Commons-logging-1.2.jar) Commons-math3-3.1.1.jarOne) Commons-net-3.1.jarCurator-client-2.7.1.jar)Curator-recipes-2.7.1.jar)Gson-2.2.4.jar)Guava-20.0.jar)Hadoop-annotations-2.8.0.jar)
When Hadoop was started today, it was discovered that Datanode could not boot, and the following errors were found in the View log: Java.io.ioexception:file/opt/hadoop/tmp/mapred/system/jobtracker.info could only is replicated to 0 nodes, instead o F 1 at Org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock (fsnamesystem.java:1271) at Org.apache.hadoop.hdfs.server.namenode.NameNode.addBl
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 ). machine preparation: the target machine must b
What is hadoop?
Before doing something, the first step is to know what, then why, and finally how ). However, after many years of project development, many developers get used to how first, then what, and finally why. This will only make them impetuous, at the same time, technologies are often misused in unsuitable scenarios.
The core designs in the hadoop framework are mapreduce and HDFS. The idea of mapre
Hadoop FS: The widest range of users can operate any file system.
Hadoop DFS and HDFs dfs: only HDFs file system related (including operations with local FS) can be manipulated, the former has been deprecated, generally using the latter.
The following reference from StackOverflow
Following are the three commands which appears same but have minute differences Hadoop
Generally, one machine in the cluster is specified as namenode, and another machine is specified as jobtracker. These machines areMasters. The remaining Machines serve as datanodeAlsoAs tasktracker. These machines areSlaves
Official Address :(Http://hadoop.apache.org/common/docs/r0.19.2/cn/cluster_setup.html) 1 prerequisites
Make sure that all required software is installed on each node of your cluster: Sun-JDK, ssh, hadoop
Javatm 1.5.x mu
Inkfish original, do not reprint commercial nature, reproduced please indicate the source (http://blog.csdn.net/inkfish).
Hadoop is an open source cloud computing platform project under the Apache Foundation. Currently the latest version is Hadoop 0.20.1. The following is a blueprint for Hadoop 0.20.1, which describes how to install
Currently in Hadoop used more than lzo,gzip,snappy,bzip2 these 4 kinds of compression format, the author based on practical experience to introduce the advantages and disadvantages of these 4 compression formats and application scenarios, so that we in practice according to the actual situation to choose different compression format.
1 gzip compression
Advantages: The compression ratio is high, and the compression/decompression speed is relatively fas
to facilitate the MapReduce direct access to the relational database (mysql,oracle). Hadoop offers two classes of Dbinputformat and Dboutputformat. Through the Dbinputformat class, the database table data is read into HDFs, and the result set generated by MapReduce is imported into the database table according to the Dboutputformat class.error when executing mapreduce: java.io.IOException:com.mysql.jdbc.Driver, usually because the program cannot find
First, compile the Hadoop pluginFirst you need to compile the Hadoop plugin: Hadoop-eclipse-plugin-2.6.0.jar Before you can install it. Third-party compilation tutorial: Https://github.com/winghc/hadoop2x-eclipse-pluginIi. placing plugins and restarting eclipsePut the compiled plugin Hadoop-eclipse-plugin-2.6.0.jar int
Now that namenode and datanode1 are available, add the node datanode2 first step: Modify the Host Name of the node to be added hadoop @ datanode1 :~ $ Vimetchostnamedatanode2 Step 2: Modify the host file hadoop @ datanode1 :~ $ Vimetchosts192.168.8.4datanode2127.0.0.1localhost127.0
Now that namenode and datanode1 are available, add the node datanode2 first step: Modify the Host Name of the node to be added
After installing the Hadoop pseudo-distributed environment, executing the relevant commands (for example: Bin/hdfs dfs-ls) will appearWARN util. nativecodeloader:unable to load Native-hadoop library for your platform ... using Builtin-java classes where applicable, which is Because the installed Navtive packages and platforms do not match, the Hadoop source packa
Org. apache. hadoop. filecache-*, org. apache. hadoop
I don't know why the package is empty. Should the package name be a class for managing File Cache?
No information was found on the internet, and no answers were answered from various groups.
Hope a Daniel can tell me the answer. Thank you.
Why is there no hadoop-*-examplesjar file after the
Hadoop Learning Note 0003--reading data from a Hadoop URLfrom Hadoopurl reading Datato from Hadoop The simplest way to read files in a file system is to use the Java.net.URL object to open a data stream from which to read the data. The general format is as follows:InputStream in = null; try {in = new URL ("Hdfs://host/path"). OpenStream (); Process i
Preface
Install the hadoop-2.2.0 64-bit version under Linux CentOS, solve two problems: first, resolve namenode cannot start, view log file logs/ Hadoop-root-namenode-itcast.out (your name is not the same as mine, see the Namenode log file on the line), which throws the following exception:Java.net.BindException:Problem binding to [xxx.xxx.xxx.xxx:9000] Java.net.BindException: Unable to specify the request
(1) First create Java projectSelect File->new->java Project on the Eclipse menu.and is named UploadFile.(2) Add the necessary Hadoop jar packagesRight-click the JRE System Library and select Configure build path under Build path.Then select Add External Jars. Add the jar package and all the jar packages under Lib to your extracted Hadoop source directory.All jar packages in the Lib directory.(3) Join the Up
This article has agreed:Dn:datanodeTt:tasktrackerNn:namenodeSnn:secondry NameNodeJt:jobtrackerThis article describes the communication protocol between the Hadoop nodes and the client.Hadoop communication is based on RPC, a detailed introduction to RPC you can refer to "Hadoop RPC mechanism introduce Avro into the Hadoop RPC mechanism"Communication between nodes
This article will go on to the wordcount example in the previous article to abstract the simplest process and explore how the System Scheduling works in the mapreduce operation process.
Scenario 1: Separate data from operations
Wordcount is the hadoop helloworld program. It counts the number of times each word appears. The process is as follows:
Now I will describe this process in text.
1. The client submits a job and sends mapreduce programs and dat
Hadoop Elephant Safari 010- using Eclipse to view Hadoop source code sinomThis is what I'm using. hadoop-1.1.2.tar.gz , this file can be downloaded at the following address:Official Address: http://archive.apache.org/dist/hadoop/core/hadoop-1.1.2/1. Unzip the
Reprint Please specify source: http://blog.csdn.net/l1028386804/article/details/51538611
The following warning message appears when you configure Hadoop to start:
WARN util. nativecodeloader:unable to load Native-hadoop library for your platform ... using Builtin-java classes where applicableThe question is where. Some people say that this is the pre-compiled Hadoop
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