Reprint Please specify source: http://blog.csdn.net/l1028386804/article/details/51538611
The following warning message appears when you configure Hadoop to start:
WARN util. nativecodeloader:unable to load Native-hadoop library for your platform ... using Builtin-java classes where applicableThe question is where. Some people say that this is the pre-compiled Hadoop
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
Preface
I still have reverence for technology.Hadoop Overview
Hadoop is an open-source distributed cloud computing platform based on the MAP/reduce model to process massive data.Offline analysis tools. Developed based on Java and built on HDFS, which was first proposed by Google. If you are interested, you can get started with Google trigger: GFS, mapreduce, and bigtable, I will not go into details here, because there are too many materials on the Int
Org. apache. hadoop. IPC. remoteException: Org. apache. hadoop. HDFS. server. namenode. safemodeexception: cannot delete/tmp/hadoop/mapred/system. name node is in safe mode.
The ratio of reported blocks 0.7857 has not reached the threshold 0.9990. Safe mode will be turned off automatically.
At org. Apache. hadoop. HDFS
DescriptionHadoop version: hadoop-2.5.0-cdh5.3.6Environment: centos6.4Must be networkedHadoop Download URL: http://archive.cloudera.com/cdh5/cdh/5/In fact, compiling is really manual work, according to the official instructions, step by step down to do it, but always meet the pit.Compile steps :1, download the source code, decompression, in this case, extracted to/opt/softwares:Command: TAR-ZXVF hadoop-2.5.
1. Introduction to HadoopHadoop is an open-source distributed computing platform under the Apache Software Foundation, which provides users with a transparent distributed architecture of the underlying details of the system, and through Hadoop, it is possible to organize a large number of inexpensive machine computing resources to solve the problem of massive data processing that cannot be solved by a single machine.
The Hadoop version of this blog is Hadoop 0.20.2.Installing Hadoop-0.20.2-eclipse-plugin.jar
To download the Hadoop-0.20.2-eclipse-plugin.jar file and add it to the Eclipse plug-in library, add a method that is simple: Locate the plugins directory under the Eclipse installation directory, copy directly to this
(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
Once Hadoop is installed, you will often be prompted with a warning:
WARN util. nativecodeloader:unable to load Native-hadoop library for your platform ...
Using Builtin-java classes where applicableSearched a lot of articles, all say is related to the system bit number, I use CentOS 6.5 64-bit operating system.
The first two days in the Docker image to find a step to solve the problem, the pro tried
Detailed procedures for starting the HDFS process using start-dfs.sh
The scripts involved are:
Under Bin:
hadoop-config.sh
start-dfs.sh
hadoop-daemons.sh
slaves.sh
hadoop-daemon.sh
Hadoop
Conf under:
hadoop-env.sh
Where both
Preface
The most interesting thing about hadoop is hadoop Job Scheduling. Before introducing how to set up hadoop, it is necessary to have a deep understanding of hadoop job scheduling. We may not be able to use hadoop, but if we understand the Distributed Scheduling Princip
Hadoop distributed platform optimization, hadoop
Hadoop performance tuning is not only its own tuning, but also the underlying hardware and operating system. Next we will introduce them one by one:
1. underlying hardware
Hadoop adopts the master/slave architecture. The master (resourcemanager or namenode) needs to mai
OneEclipse Import Hadoop Source projectBasic steps:1) Create a new Java project "hadoop-1.2.1" in Eclipse2) Copy the Core,hdfs,mapred,tools,example four directory under the directory src of the Hadoop compression package to the SRC directory of the new project above3) Right click to select Build path, modify Java Build path "source", delete src, add src/core,src/
In Hadoop, data processing is resolved through the MapReduce job. Jobs consist of basic configuration information, such as the path of input files and output folders, which perform a series of tasks by the MapReduce layer of Hadoop. These tasks are responsible for first performing the map and reduce functions to convert the input data to the output results.
To illustrate how MapReduce works, consider a simp
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
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
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
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.