All datanode operations in the hadoop cluster are unfavorable (solution)
Datanode cannot be started only in the following situations.
1. First, modify the configuration file of the master,
2. Bad habits of hadoop namenode-format for multiple times.
Generally, an error occurs:
Java. io. IOException: Cannot lock storage/usr/had
Address: http://blog.cloudera.com/blog/2013/04/how-to-use-vagrant-to-set-up-a-virtual-hadoop-cluster/
Vagrant is a very useful tool that can be used to program and manage multiple virtual machines (VMS) on a single physical machine ). It supports native virtualbox and provides plug-ins for VMWare Fusion and Amazon EC2 Virtual Machine clusters.
Vagrant provides an easy-to-use ruby-based internal DSL that all
Yesterday because Datanode appeared large-scale offline situation, the preliminary judgment is dfs.datanode.max.transfer.threads parameter set too small. the hdfs-site.xml configuration files for all Datanode nodes are then adjusted. After restarting the cluster, in order to verify, try to run a job, see the configuration of the job in Jobhistory, it is surprising that the display is still the old value, that is, the job is still running with the old
Hadoop advanced 1. Configure SSH-free (1) Modify the slaves fileSwitch to master machine, this section is all done in master.Enter the/usr/hadoop/etc/hadoop directory, locate the slaves file, and modify:slave1slave2slave3(2) Sending the public keyEnter the. SSH directory under the root directory:
Generate Public Private key
SSH-KEYGEN-T RSA
Hadoop generation cluster running code case
Cluster a master, two slave,ip are 192.168.1.2, 192.168.1.3, 192.168.1.4 Hadoop version is 1.2.1
First, start Hadoop
go to the bin directory of Hadoop
second, the establishment of data
The main process for installing and setting up Hadoop under Ubuntu.1. Create a Hadoop userCreate a user named Hadoop and create the user's home directory under home without detailed description.2. Installing the Java EnvironmentDownload the jdk:jdk-8u111-linux-x64.tar.gz under Linux environment.Create a Java folder under USR, copy the jdk-8u111-linux-x64.tar.gz t
Hadoop cluster itself is not recommended to store small files, because in the MapReduce program scheduling process, the default map input is not cross-file, if a file is small (much smaller than the size of a block, the current cluster block size is 256M), the scheduling will also generate a map, and a map only processes this small file, so that the MapReduce pro
Overview: Hadoop cluster, 1 sets of Namenode, a secondnamenode, a jobtracker and Taiwan Datanode, the specific installation method on the Internet there are too many, the following is just their own set up the experimental environment and the problem solution. 1, the configuration IP corresponding hostname/etc/hosts configuration namenode and Datanode, shape as follows:
192.168.1.1 Namenode
192.168.1.2 Seco
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Add hard disks to the Hadoop cluster.
Hadoop worker nodes expand hard disk space
After receiving the task from the boss, the hard disk space in the Hadoop cluster is insufficient, and a machine is required to be added to the Hadoop
Section 131 :Hadoop Cluster management tool equalizer Balancer The actual combat detailed study notesWhy do I need a equalizer?As the cluster runs, the block on each data storage node in HDFs may be distributed more and more unevenly, resulting in reduced MapReduce locality when running the job . One of the essence of distributed computing: data does not move cod
First run MapReduce, recorded several problems encountered, Hadoop cluster is CDH version, but my Windows local jar package is directly with hadoop2.6.0 version, and did not specifically look for CDH version of the1.Exception in thread "main" Java.lang.NullPointerException Atjava.lang.ProcessBuilder.startDownload Hadoop2 above version, in the Hadoop2 bin directory without Winutils.exe and Hadoop.dll, find t
/jobtoken at Org.apache.hadoop.security.Credentials.readTokenStorageFile (Credentials.java:135) at Org.apache.hadoop.mapreduce.security.TokenCache.loadTokens (tokencache.java:165) at org.apache.h Adoop.mapred.TaskTracker.initializeJob (tasktracker.java:1179) at Org.apache.hadoop.mapred.TaskTracker.localizeJob (tasktracker.java:1116) at org.apache.hadoop.mapred.tasktracker$ 5.run (tasktracker.java:2404) at Java.lang.Thread.run (thread.java:744) caused by:java.io.FileNotFoundException:File File:/
Hadoop's balance tools are typically used to balance the file block distribution in each datanode in a Hadoop cluster while on-line Hadoop cluster operations. To avoid the problem of a high percentage of datanode disk usage (which is also likely to cause the node to have higher CPU utilization than other servers).
1) u
The production environment of Hadoop cluster installation and configuration + DNS + NFS environment LinuxISO: CentOS-6.0-i386-bin-DVD.iso32 bit JDKversion: 1.6.0 _ 25-eaforlinuxHad ..
The production environment of Hadoop cluster installation and configuration + DNS + NFS environment LinuxISO: CentOS-6.0-i386-bin-DVD.is
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