Hadoop learning 2: hadoop LearningAfter building a pseudo-distributed system:Introduction to pseudo distributed installation: http://www.powerxing.com/install-hadoop/
Exercise 1 compile a Java program to implement the followingFunction:
1. In HDFSUpload files
2. From HDFSDownload filesTo local
3.Show file directory
4.Move files
5.Create folder
6.Remove folder
everything is OK on the Namenode node, and there is no prompt for this information, but the following message appears on Datanode:15/01/14 16:42:09 WARN util. nativecodeloader:unable to load Native-hadoop library for your platform ... using Builtin-java classes where applicableafter checking the original is Datanode sub-node /home/hadoop/hadoop2.2/lib directory does not have native folder, and Namenode abov
Hadoop ++ is a non-invasive Optimization of hadoop map reduce. It improves query and connection performance by customizing functions such as split in hadoop framework. The project is hosted by Professor Jens dittrich at the University of Saarland, Germany. The project homepage is http://infosys.uni-saarland.de/hadoop?#
Original article: http://hadoop.apache.org/common/docs/r0.23.0/hadoop-yarn/hadoop-yarn-site/CapacityScheduler.html
This document describes capacityscheduler, a pluggable hadoop scheduler that allows multiple users to securely share a large cluster, their applications can obtain the required resources within the capacity limit.
Overview
Capacityscheduler is design
, file random modification a file can have only one writer, only support append.Data form of 3.HDFSThe file is cut into a fixed-size block, the default block size is 64MB, the size of the block can be configured, if the file size is less than 64MB, it is stored separately into a block. A file storage method is divided into blocks by size, stored on different nodes, with three replicas per block by default.HDFs Data Write Process: HDFs Data Read process: 4.MapReduce: Google's MapReduce open sou
Deploy Hadoop cluster service in CentOSGuideHadoop is a Distributed System infrastructure developed by the Apache Foundation. Hadoop implements a Distributed File System (HDFS. HDFS features high fault tolerance and is designed to be deployed on low-cost hardware. It also provides high throughput to access application data, suitable for applications with large datasets. HDFS relaxed the requirements of POSI
containers. This timeout time can be passed through the top-level elementAnd element-level elementsConfigure the time-out time for all queues and a queue respectively. The ratio mentioned above can be(Configure all queues) and(Configure a queue). The default value is 0.5.
Hadoop2.3-HA high-availability cluster environment construction
Hadoop project-Cloudera 5.10.1 (CDH) installation and deployment based on CentOS7
Detailed explanation of Hadoop2.7.2
High-availability Hadoop platform-Hadoop Scheduling for Oozie Workflow1. Overview
In the "high-availability Hadoop platform-Oozie Workflow" article, I will share with you how to integrate a single plug-in such as Oozie. Today, we will show you how to use Oozie to create related workflows for running and Hadoop. You mu
Several Hadoop daemon and Hadoop daemon
After Hadoop is installed, several processes will appear when jps is used.
Master has:
Namenode
SecondaryNameNode
JobTracker
Slaves has
Tasktracker
Datanode
1.NameNode
It is the master server in Hadoop, managing the file system namespace and accessing the files stored in the
resourcesMaster-Slave structureMaster node, there can be 2: ResourceManagerFrom the node, there are a number of: NodeManagerResourceManager is responsible for:Allocation and scheduling of cluster resourcesFor applications such as MapReduce, Storm, and Spark, the Applicationmaster interface must be implemented to be managed by RMNodeManager is responsible for:Management of single node resourcesVII: The architecture of MapReduceBatch computing model with disk IO dependentMaster-Slave structureMas
Big data: Massive dataStructured data: Data that can be stored in a two-dimensional tableunstructured data: Data cannot be represented using two-dimensional logic of the data. such as word,ppt, picture Semi-structured data: a self-describing, structured and unstructured data that stores the structure with the data itself: XML, JSON, HTMLGoole paper: mapreduce:simplified Date processing on Large Clusters Map: Small data that maps big data to multiple nodes that are segmented
First on the correct run display:Error 1: The variable is intwritable and is receiving longwritable, such as:Reason, write more parameters reporter, such as:Error 2: The array is out of bounds, such as:Cause: The Combine class is set up, such as:Error 3:nullpointerexception exception, such as:Cause: The static variable is null and can be assigned, such as:Error 4: Entering map, but unable to enter reduce, and direct map data output, and no error promptCause: The new and older version of
1 access to Apache Hadoop websitehttp://hadoop.apache.org/2.2. Click image to downloadWe download the 2.6.0 third in the stable version of stableLinux Download , here is an error, we download should be the bottom of the second, which I did not pay attention to download the above 17m .3. Install a Linux in the virtual machineFor details see other4. Installing the Hadoop environment in Linux1. Installing the
Run Hadoop WordCount. jar in Linux.
Run Hadoop WordCount in Linux
Enter the shortcut key of Ubuntu terminal: ctrl + Alt + t
Hadoop launch command: start-all.sh
The normal execution results are as follows:
Hadoop @ HADOOP :~ $ Start-all.sh
Warning: $ HADOOP_HOME is deprecate
command to upload data to HDFs, if the log server data is large, the pressure is higher, using NFS to upload data on another server, if the log server is very large, data volume, using flume for data processing;2.2 Write a MapReduce program to clean the data in HDFs;2.3 Using hive to statistics the data after cleaning;2.4 The statistic data is exported to MySQL via Sqoop;2.5 If you need to view detailed data, you can show through HBase;3 Detailed Overview3.1 Uploading data from Linux to HDFs us
Hadoop big data basic training course: the only full HD version of the first season, hadoop Training CourseHadoop big data basic training course unique HD full version first seasonThe full version of 30 lessons was born
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The most comprehensive history of hadoop, hadoop
The course mainly involves the technical practices of Hadoop Sqoop, Flume, and Avro.
Target Audience
1. This course is suitable for students who have basic knowledge of java, have a certain understanding of databases and SQL statements, and are skilled in using linux systems. It is especially suitable for those who
Briefly describe these systems:Hbase–key/value Distributed DatabaseA collaborative system for zookeeper– support distributed applicationsHive–sql resolution Engineflume– Distributed log-collection system
First, the relevant environmental description:S1:Hadoop-masterNamenode,jobtracker;Secondarynamenode;Datanode,tasktracker
S2:Hadoop-node-1Datanode,tasktracker;
S3:Had
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
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