hadoop net

This article is derived from the deep analysis of Hadoop Technology Insider design and implementation principles of Hadoop common and HDFs architectureFirst, the basic concept of Hadoop Hadoop is an open source distributed computing platform under the Apache Foundation, with the core of the

I. Introduction to the Hadoop releaseThere are many Hadoop distributions available, with Intel distributions, Huawei Distributions, Cloudera Distributions (CDH), hortonworks versions, and so on, all of which are based on Apache Hadoop, and there are so many versions is due to Apache Hadoop's Open source agreement: Anyone can modify it and publish/sell it as an op

1. Install hadoop First, extract the downloaded hadoop 0.20 package to the/home/Admin directory: Tar xzfhadoop-0.20.2.tar.gz Configure hadoop environment variables: Exporthadoop_install =/home/admin/hadoop-0.20.2 Exportpath = $ path: $ hadoop_install/bin Test whether the installation is successful:

First, download the Hadoop websitehttp://hadoop.apache.orghttps://archive.apache.org/dist/hadoop/common/hadoop-2.6.0 Administrator Identity Decompression D:\Hadoop\hadoop-2.6.0Second, the download of winutilsAlso need to download Winutils.exe,requires a corresponding version

Part 1: hadoop BinThe following hadoop bin is based on the actual needs of the project:Hadoop ShellHadoop-config.sh, which is used to assign values to some variablesHadoop_home (hadoop installation directory ).Hadoop_conf_dir (hadoop configuration file directory ). Hadoop_slaves (-- the address of the file specified by

Ubuntu installation (Here I do not catch a map, just cite a URL, I believe that everyone's ability)Ubuntu Installation Reference Tutorial: http://jingyan.baidu.com/article/14bd256e0ca52ebb6d26129c.htmlNote the following points:1, set the virtual machine's IP, click the network connection icon in the bottom right corner of the virtual machine, select "Bridge mode", so as to assign to your LAN IP, this is very important because the back Hadoop to use th

now let's take a closer look at the FileSystem class for Hadoop. This class is used to interact with Hadoop's file system. While we are mainly targeting HDFS here, we should let our code use only abstract class filesystem so that our code can interact with any Hadoop file system. When we write the test code, we can test it with the local file system, use HDFs when deploying, just configure it, no need to mo

Http://devsolvd.com/questions/hadoop-unable-to-load-native-hadoop-library-for-your-platform-error-on-centos The answer depends ... I just installed Hadoop 2.6 from Tarball on 64-bit CentOS 6.6. The Hadoop install did indeed come with a prebuilt 64-bit native library. For my install, it's here: /opt/

Read files For more information about the file reading mechanism, see: The client calls the open () method of the filesystem object (corresponding to the HDFS file system, and calls the distributedfilesystem object) to open the file (that is, the first step in the figure ), distributedfilesystem uses Remote Procedure Call to call namenode to obtain the location of the first several blocks of the file (step 2 ). For each block, namenode returns the address information of all namenode that owns t

in the Hadoop Eclipse Development Environment Building In this article, the 15th.) mentions permission-related exceptions, as follows:15/01/30 10:08:17 WARN util. nativecodeloader:unable to load Native-hadoop library for your platform ... using Builtin-java classes where applicable15/ 01/30 10:08:17 ERROR Security. Usergroupinformation:priviledgedactionexception As:zhangchao3 cause:java.io.IOException:Faile

Pre-Preparation 1. Create a Hadoop-related directory (easy to manage) 2, give Hadoop users and all group permissions to the/opt/* directorysudo chrown-r hadoop:hadoop/opt/*3, JDK installation and configuration configuration Hdfs/yarn/mamreduce1, decompression HadoopTAR-ZXF hadoop-2.5.0.tar.gz-c/opt/modules/(delete Doc's help document, save space) rm-rf/opt/module

-p '-F/HOME/U/.SSH/ID_DSASsh-keygen indicates that the key is generated-T means the specified generated key typeDSA is the meaning of DSA key authentication, that is, the key type-P provides a passphrase-f Specifies the generated key file(4) # cat/home/u/.ssh/id_dsa.pub >>/home/u/.ssh/authorized_keys# Add the public key to the public key file for authentication, Authorized_keys is the public key file for authentication(5) # Ssh-version# Verify that SSH installation is complete and the correct in

additional openssh-clients(3) # Mkdir-p ~/.ssh # Assume that after you install SSH, these folders are not actively generated by yourself, please create your own(4) # ssh-keygen-t Dsa-p "-F ~/.SSH/ID_DSASsh-keygen indicates that the key is generated-T means the specified generated key typeDSA is the meaning of DSA key authentication, that is, the key type-P provides a passphrase-f Specifies the generated key file(5) # cat ~/.ssh/id_dsa.pub >> ~/.ssh/authorized_keys# Add the public key to the pub

Knowing and learning about Hadoop, we have to understand the composition of Hadoop, and based on my own experience, I introduce the Hadoop component, the big data processing process, and the three aspects of Hadoop core: Hadoop Components 650) this.width=650;

in ~/.ssh/: Id_rsa and id_rsa.pub; These two pairs appear, similar to keys and locks.Append the id_rsa.pub to the authorization key (there is no Authorized_keys file at this moment)$ cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys(3) Verify that SSH is installed successfullyEnter SSH localhost. If the display of a native login succeeds, the installation is successful.3. Close the firewall $sudo UFW disableNote: This step is very important, if you do not close, there will be no problem finding D

As you know, Namenode has a single point of failure in the Hadoop system, which has been a weakness for high-availability Hadoop. This article discusses several solution that exist to solve this problem. 1. Secondary NameNode principle: secondary NN periodically reads the editlog from the NN, merging with the image that it stores to form a new metadata image advantage: The earlier version of

Make sure that the three machines have the same user name and install the same directory *************SSH Non-key login simple introduction (before building a local pseudo-distributed, it is generated, now the three machines of the public key private key is the same, so the following is not configured)Stand-alone operation:Generate Key: Command ssh-keygen-t RSA then four carriage returnCopy the key to native: command Ssh-copy-id hadoop-senior.zuoyan.c

1, the main learning of Hadoop in the four framework: HDFs, MapReduce, Hive, HBase. These four frameworks are the most core of Hadoop, the most difficult to learn, but also the most widely used.2, familiar with the basic knowledge of Hadoop and the required knowledge such as Java Foundation,Linux Environment, Linux common commands 3. Some basic knowledge of Hadoo

Using HDFS to store small files is not economical, because each file is stored in a block, and the metadata of each block is stored in the namenode memory. Therefore, a large number of small files, it will eat a lot of namenode memory. (Note: A small file occupies one block, but the size of this block is not a set value. For example, each block is set to 128 MB, but a 1 MB file exists in a block, the actual size of datanode hard disk is 1 m, not 128 M. Therefore, the non-economic nature here ref

grouping (partition) The Hadoop streaming framework defaults to '/t ' as the key and the remainder as value, using '/t ' as the delimiter,If there is no '/t ' separator, the entire row is key; the key/tvalue pair is also used as the input for reduce in the map.-D stream.map.output.field.separator Specifies the split key separator, which defaults to/t-D stream.num.map.output.key.fields Select key Range-D map.output.key.field.separator Specifies the se