Exception Analysis
1. "cocould only be replicated to 0 nodes, instead of 1" Exception
(1) exception description
The configuration above is correct and the following steps have been completed:
[Root @ localhost hadoop-0.20.0] # bin/hadoop namenode-format
[Root @ localhost hadoop-0.20.0] # bin/start-all.sh
At this time, we can see that the five processes jobtracke
Hadoop datanode node time-out settingDatanode process death or network failure caused datanode not to communicate with Namenode,Namenode will not immediately determine the node as death, after a period of time, this period is temporarily known as the timeout length.The default timeout period for HDFs is 10 minutes + 30 seconds. If the definition time-out is timeout, the time-out is calculated as:Timeout = 2 * heartbeat.recheck.interval + ten * dfs.hea
This section mainly analyzes the principles and processes of mapreduce.
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You must at least know the following points about mapreduce:
1. map
1. Concept2. ReferencesImprove the MapReduce job Efficiency Note II of Hadoop (use combiner as much as possible): Http://sishuo (k). com/forum/blogpost/list/5829.htmlHadoop Learning notes -8.combiner and custom Combiner:http://www.tuicool.com/articles/qazujavHadoop in-depth learning: combiner:http://blog.csdn.net/cnbird2008/article/details/23788233(mean Scene) 0Hadoop using combiner to improve Map/reduce program efficiency: http://blog.csdn.net/jokes0
from the Agent cannot be received.请确保主机的名称已正确配置。请确保端口 7182 可在 Cloudera Manager Server 上访问(检查防火墙规则)。请确保正在添加的主机上的端口 9000 和 9001 空闲。检查正在添加的主机上 /var/log/cloudera-scm-agent/ 中的代理日志(某些日志可在安装详细信息中找到)。Could not find config file/var/run/cloudera-scm-agent/supervisor/supervisord.confThe solution to this error is:After we have modified our/etc/hosts file, we have to restart the service cloudera-scm-agentService Cloudera-scm-agent Restart8. Cannot be displayed after installing cm9, 7180 interface cannot op
Setting up Hadoop cluster environment steps under Ubuntu 12.04I. Preparation before setting up the environment:My native Ubuntu 12.04 32bit as Maser, is the same machine that was used in the stand-alone version of the Hadoop environment, http://www.linuxidc.com/Linux/2013-01/78112.htmAlso in the KVM Virtual 4 machines, respectively named:Son-1 (Ubuntu 12.04 32bit),Son-2 (Ubuntu 12.04 32bit),Son-3 (CentOS 6.
FS ShellThe call file system (FS) shell command should use the form Bin/hadoop FS scheme://authority/path. For the HDFs file system, Scheme is HDFs, to the local file system, scheme is file. The scheme and authority parameters are optional, and if not specified, the default scheme specified in the configuration is used. An HDFs file or directory such as /parent/child can be represented as Hdfs://namenode:namenodeport/parent/child, or simpler /parent/
VMware has installed Multiple RedHatLinux operating systems, excerpted a lot of online materials, and installed them in order? 1. Create groupaddbigdatauseradd-gbigdatahadooppasswdhadoop? 2. Create JDKvietcprofile? ExportJAVA_HOMEusrlibjava-1.7.0_07exportCLASSPATH.
VMware has installed Multiple RedHat Linux operating systems, excerpted a lot of online materials, and installed them in order? 1. Create groupadd bigdata useradd-g bigdata hadoop passwd
Hadoop Learning Notes
Author: wayne1017
first, a brief introduction
Here is a general introduction to Hadoop.Most of this article is from the official website of Hadoop. One of them is an introduction to HDFs's PDF document, which is a comprehensive introduction to Hadoop. My this series of Hadoop learning Notes is al
1 Hadoop configurationcaveats: Turn off all firewalls
server
ip
system
master
centos 6.0 X64
slave1
10.0.0.11
Centos 6.0 X64
slave2
10.0.0.12
centos 6.0 X64
Hadoop version: hadoop-0.20.2.tar.gz1.1 in master: (Operations
Hadoop pseudo-distribution installation steps, hadoop Installation Steps2. steps for installing hadoop pseudo-distribution: 1.1 set the static IP address icon in the upper-right corner of the centos desktop, right-click to modify and restart the NIC, and run the Command service network restart for verification: ifconfig 1.2 modify the host name
Hadoop is a distributed storage and computing platform for Big dataArchitecture of HDFs: Master-Slave architectureThe primary node has only one namenode, and there can be many datanode from the node.Namenode is responsible for:(1) Receiving User action request(2) Maintaining the directory structure of the file system(3) Managing the relationship between the file and block, and the connection between block and DatanodeDatanode is responsible for:(1) St
Hadoop has a distributed system called HDFS , all known as Hadoop distributed Filesystem.HDFs has a block concept, and the default is that the file on 64mb,hdfs is divided into chunks of block size, as separate storage units. The advantage of using blocks is: 1. A file size can be larger than the capacity of any disk in the cluster network, and all blocks of the file do not need to be stored on the same dis
P3-P4:The problem is simple: the capacity of hard disk is increasing, 1TB has become the mainstream, however, data transmission speed has risen from the 1990 4.4mb/s only to the current 100mb/sReading a 1TB hard drive data takes at least 2.5 hours. Writing the data consumes more time. The workaround is to read from multiple hard drives, imagine that if there are currently 100 disks, each disk stores 1% data, then the parallel reads only need 2minutes to read all the data.At the same time, parall
The following error is reported:Workaround:1. Increase Debugging informationAdd the following information in the hadoop_home/etc/hadoop/hadoop-env.sh file2. Perform another operation to see what errors are reportedThe above information shows that 2.14 GLIBC library is requiredWorkaround:1. View the libc version of the system (LL/LIB64/LIBC.SO.6)Display version is 2.12The first solution, using the 2.12 versi
Apache Hadoop Ecosystem installation package: http://archive.apache.org/dist/Software Installation directory: ~/appjdk:jdk-7u45-linux-x64.rpmhadoop:hadoop-2.5. 1-src. Tar . Gzmaven:apache-maven-3.0. 5-bin. Zip protobuf:protobuf-2.5. 0. tar. gz1. Download Hadoopwget http://tar -zxvf hadoop-2.5. 1-src. TarThere is a BUILDING.txt file under the extracted Hadoop root
the RM with several HA-related options and switches the Active/standby mode. The HA command takes the RM service ID set by the Yarn.resourcemanager.ha.rm-ids property as the parameter.$ yarn rmadmin-getservicestate rm1 Active $ yarn rmadmin-getservicestate RM2 StandbyIf automatic recovery is enabled, then you can switch commands without having to manually.$ yarn Rmadmin-transitiontostandby rm1 Automatic failover is enabled for [email protected] refusing to manually manage HA State, since it cou
-generated Method StubFile docdirectory=NewFile (Docdirectorypath); if(!docdirectory.isdirectory ()) {System.out. println ("Provide an absolute path of a directory that contains the documents to be added to the sequence file"); return; } /** Sequencefile.writer sequencefilewriter = * Sequencefile.createwriter (FS, Conf, new Path (Sequencefil Epath), * text.class, Byteswritable.class); */org.apache.hadoop.io.SequenceFile.Writer.Option FilePath=sequencefile.writer. File (NewPath (Se
insideLet's modify the hostTwo comments out of the front.6. Configure the Yum source6.1 Copying filesDelete the repo file that comes with the system in the/ETC/YUM.REPOS.D directory firstWill: Create a new file: Cloudera-manager.repoTouch Cloudera-manager.repoThe contents of the file are:BaseURL back is the folder inside your var/www/html.baseurl=http://Correct the second time you do itThird Amendment[Cloudera-manager]Name=cloudera ManagerBaseURL = Http://192.168.42.99/cdh/cm5.3/packageGpgcheck
.el6.noarch.rpm/download/# Createrepo.When installing Createrepo here is unsuccessful, we put the front in Yum.repo. Delete something to restoreUseyum-y Installcreaterepo Installation TestFailedAnd then we're on the DVD. It says three copies of the installed files to the virtual machine.Install deltarpm-3.5-0.5.20090913git.el6.x86_64.rpm FirstError:Download the appropriate rpmhttp://pkgs.org/centos-7/centos-x86_64/zlib-1.2.7-13.el7.i686.rpm/download/Http://pkgs.org/centos-7/centos-x86_64/glibc-2
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