Document directory
1. Read the compressed input file directly
2. compress the intermediate results produced by mapreduce job
3. compress the final computing output results
4. is the use of hadoop-0.19.1 to compare a task with three compression methods:
5. For more information about how to use lzo with high compression and compression, see the following url.
Hadoop supports multiple compression met
Because Hadoop is still in its early stage of rapid development, and it is open-source, its version has been very messy. Some of the main features of Hadoop include:
Append: Supports file appending. If you want to use HBase, you need this feature.
RAID: to ensure data reliability, you can introduce verification codes to reduce the number of data blocks. Link: https://issues.apache.org/jira/browse/HDFS/c
Write scalable, distributed data-intensive programs and basics
Understanding Hadoop and MapReduce
Write and run a basic MapReduce program
1. What is HadoopHadoop is an open-source framework for writing and running distributed applications to handle large-scale data.What makes Hadoop unique is the following points:
Convenient--hadoop run on a
Environment[Email protected] soft]#Cat/etc/Issuecentos Release6.5(Final) Kernel \ r \m[[email protected] soft]#uname-Alinux vm80282.6. +-431. el6.x86_64 #1SMP Fri Nov A Geneva: the: theUtc -x86_64 x86_64 x86_64 gnu/Linux[[email protected] soft]# Hadoop versionhadoop2.7.1Subversion https://git-wip-us.apache.org/repos/asf/hadoop.git-r 15ecc87ccf4a0228f35af08fc56de536e6ce657aCompiled by Jenkins on -- .-29t06:04zcompiled with Protoc2.5.0From source with c
1. The virtual machine installation hadoop,windows cannot access the Hadoop Web page http://master:50070/through the host name. Windows Ping Master also pings the method: Add Linux under Windows native C:\Windows\System32\drivers\etc\hosts files Hosts configure the hostname and IP address of the Hadoop machine to add in.
Issue 2, Windows Eclipse runni
: $CLASSPATHExport path= $JAVA _home/bin: $JRE _home/bin: $PATHAfter the configuration is complete, the effect is:650) this.width=650; "src=" Http://s1.51cto.com/wyfs02/M02/7F/55/wKiom1caCGHyJd5fAAAf48Z-JKQ416.png "title=" 7.png " alt= "Wkiom1cacghyjd5faaaf48z-jkq416.png"/>3. No password login between nodesSSH settings require different operations on the cluster, such as start-up, stop, and distributed daemon shell operations. Authenticating different Hadoop
Hadoop is a platform for storing massive amounts of data on distributed server clusters and running distributed analytics applications, with the core components of HDFS and MapReduce. HDFS is a distributed file system that can read distributed storage of data systems;MapReduce is a computational framework that distributes computing tasks based on Task Scheduler by splitting computing tasks. Hadoop is an ess
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
Hadoop version 1.2.1
Jdk1.7.0
Example 3-1: Use the urlstreamhandler instance to display files of the hadoop File System in standard output mode
hadoop fs -mkdir input
Create two files, file1, file2, and file1, as Hello world, and file2 as Hello hadoop, and then upload the files to the input file. The specific method i
Wang Jialin's in-depth case-driven practice of cloud computing distributed Big Data hadoop in July 6-7 in Shanghai
This section describes how to use the HDFS command line tool to operate hadoop distributed clusters:
Step 1: Use the hsfs command to store a large file in a hadoop distributed cluster;
Step 2: delete the file and use two copies to s
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
Description: Compile hadoop program using eclipse in window and run on hadoop. the following error occurs:
11/10/28 16:05:53 info mapred. jobclient: running job: job_201110281103_000311/10/28 16:05:54 info mapred. jobclient: Map 0% reduce 0%11/10/28 16:06:05 info mapred. jobclient: task id: attempt_201110281103_0003_m_000002_0, status: FailedOrg. apache. hadoop.
Hadoop interview questions (1) and hadoop interview questions
I. Q :
1. Briefly describe how to install and configure an apache open-source version of hadoop. You only need to describe it. You do not need to list the complete steps and the steps are better.
1) install JDK and configure environment variables (/etc/profile)
2) disable the Firewall
3) configure the
Today the Hadoop authoritative Guide Weather Data sample code runs through the Hadoop cluster and records it.
Before the Baidu/google how also did not find how to map-reduce way to run in the cluster every step of the specific description, after a painful headless fly-style groping, success, a good mood ...
1 Preparing the Weather forecast data (simplified version of the data on the authoritative guide 5-9
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;
We know that the Hadoop cluster is fault-tolerant, distributed and so on, why it has these characteristics, the following is one of the principles.
Distributed clusters typically contain a very large number of machines, and due to the limitations of the rack slots and switch ports, the larger distributed clusters typically span several racks, and the machines on multiple racks form a distributed cluster. The network speed between the machines in the
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.