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.
Complete release directory of "cloud computing distributed Big Data hadoop hands-on"
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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
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
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
(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
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
The compilation process is very long, the mistakes are endless, need patience and patience!! 1. Preparation of the environment and software
Operating system: Centos6.4 64-bit
JDK:JDK-7U80-LINUX-X64.RPM, do not use 1.8
Maven:apache-maven-3.3.3-bin.tar.gz
protobuf:protobuf-2.5.0.tar.gz Note: Google's products, preferably in advance Baidu prepared this document
Hadoop src:hadoop-2.5
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
I was fortunate enough to take the MOOC college Hadoop experience class at the academy. This is the little Elephant College hadoop2. X Overview Notes for chapter eighthThe main introduction is HBase, a distributed database application case.Case Overview:1) Time series database (OPENTSDB) Use HBase to store time series data, every moment is resolved, the database is open source 2) hbase Crawler Scheduler Library Vertical Search Crawler Mass crawler (wh
Hadoop is a project under Apache. It consists of HDFS, mapreduce, hbase, hive, Zookeeper, and other Members. HDFS and mapreduce are two of the most basic and important members.
HDFS is an open-source version of Google gfs. It is a highly fault-tolerant distributed file system that provides high-throughput data access and is suitable for storing massive (Pb-level) data) (usually more than 64 MB), the principle is as follows:
The Master/Slave struct
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1. The principles have been described in the diagram, not another large paragraph of text explained, 2. In the above two diagrams, except for the "actual business object class", all belong to the structure or frame part; 3. If you use OO thinking to review the above two charts, you will be complaining about the bad design, here just to describe the work of the distributed system as simple as possible, you can use the policy mode to ada
Hadoop exception and handling Summary-01 (pony-original), hadoop-01
Test environment:
Local: MyEclipse
Cluster: Vmware 11 + 6 Centos 6.5
Hadoop version: 2.4.0 (configured as automatic HA)
Test Background:
After four normal tests of the MapReduce Program (hereinafter referred to as MapReduce), a new MR program is executed, and the console information of MyEclipse
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